I was wondering if any of you have ever overheated on a long grade before. We overheated (well got to the max cummins recommends) today in 3rd gear at 40mph, 1900rpm pulling the grade on 50west from Reno into Lake Tahoe. It was an absolutely ridiculous climb, from 4000 to 7000 feet in only a few miles. Felt like 8-10% grade. It seemed to go on forever. Even so I was surprised to see the temperature keep climbing. I stopped at around 210 degrees and ran it on high idle for it to cool down. Not sure if I should have packed it in earlier. We disconnected our heavy toad and it was at 180 the rest of the climb (but we were already almost done). It's a very odd thing to have so much power and not enough cooling capacity. Our old gas motorhome threatened to go backwards on nearly every hill but it wouldn't overheat even in 100 degree heat.
Now Lake Tahoe traffic, that was another story :o
Hi piku,
Was that temp from the dash gauge? If so, you might not be that warm. I thought our Cummins engine would go into a shut down, or alarm, if it was overheating.
Raymond
Countless discussions of this with customers and industry people starting in 1985.
Personal experience today on a similar hill. Came over grapevine, ca at 5pm today coming from yosemite.
Started up the grade at 86 degrees ambient.
Coach ended up at 52mph at 1,700 in fourth. Floored.
Dash temp gauge pegged at a similar 210.
Five or six miles later the top was reached and the temp slowly dropped as the 3,000 pounds of engine and trans and cooling system cooled off.
You had nothing wrong IMO.
Everyone panics if the temp gauge moves. Do not.....
Repeated personal tests of multiple coaches and brands up steep grades at full power has shown me and my,customers to admire the cooling systems design from Foretravel.
Hard to overheat. My respects to the 6v92 people who know their engines will fail over 210(my personsal long term testings says no) but your coach is fine.
Actually its perfect IMO.
And I have driven diesel pusher coaches in the Rockies since 1984.
Every owner panicked if the temp gauge moved.
No coach has enough reserve cooling to not have the temp gauge move and the cooling fan increase its speed to add cooling.
Wish I could have had the skeptics with me today up Tejon grade. Taken countless customers up the same hills to prove to them it won't melt down.
My money. My coach. Been to 225 engine temp at 102 ambient. Exactly the same engine temp difference as the ambient temps were.
The same results I noticed in the 80's delivering coaches though the desert to Vegas.
Temp gauge was 210 at 80 degrees up Baker grade(17 mile grade) 240 at 110 outside.
Same hill. Similar new coach. Multiple coaches in both seasons. Me driving.
Sorry for the long explanation but after dozens of drives to prove what I am posting without a single problem or long term issue with coaches I feel qualified to post this.
Trust me. It normal. Notice no warning lights came on? Dead giveaway.
Bob.
Go ahead tell me you had problems after 210 or 220?
I may be wrong but on the M11 it doesn't send an error code until 220F. I think you will get an engine shutdown 30 seconds after the error code. Now at 210F steady state I wouldn't be concerned enough to shut down, but I would likely reduce power a little. If it was 210F and rising, I would definitely reduce power and let the coolant system catch up. I would also get my gauge checked. A 15 year old gauge is not likely to be that accurate. It could easily be wrong in either direction. That is one thing I like about the VMSpc, it gives you the digital data the computer is seeing and you can see the parameter changes over time letting you now if you are rapidly or slowly reaching a limit situation.
200F is my limit on my 6V92. Once I hit that mark, I reduce speed and power until it cools down. However, I grew up with the old 2 strokes in trucks. We frequently got 300K+ on an engine before anything other than regular maintenance had to be done. My all time record was a little over 400K on a 8V71.
You can certainly run these engines at higher temps than I do; but you will be working on them before you hit 200K.
On the other hand, most motor homes don't last that long. I had hoped Foretravel, like Bluebirds, were on the list of those that do.
I have no experience with the newer engines, but other mechanics I know tell me they will tolerate and in some cases thrive at higher temperatures.
I like what Bob said: My coach & my money, I drive it like I want! ;D ;D
TOM
The Cummins M 11 is a long life engine. With reasonable care, you can easily expect 600K miles. With the Detroit series 60, you might get 1,000,000 miles. Either one will out last the old two bangers, but I do love those 2 stroke Detroits ---- I grew up in the marine industry with the 71 series. I'm pretty sure the Foretravel chassis will outlast me if I take care of it. They are well built and durable.
With good care you can get over a million miles on an M11
Roland
I'd have to agree with all these folks who know more about this stuff than I do... the only caveat I'd add is that this assumes your cooling system is in good shape, radiator not clogged and such, that it's OK for things to get that warm climbing that hill. You ain't kiddin, that is one serious grade, and you're pushing many tons up it... but it's commercial-grade big truck hardware doing the pushing. Our old u280 with the lil kittykat engine handled some truly long hard climbs on our Yellowstone trip without complaining, it was amazing and gratifying to see just how fast temp would come back down once we reached the crest. Many's the time we had to park out SOB to let it cool off...
One reason we LOVE having the Silverleaf display ... you can read the "load" on the engine and the temperatures when you hit an area like that. We learned how to adjust gears and speed to keep the load in a good range and can only imagine what we were doing before that education!
i have hit 210 before on a long grad with an outside temp of 108 in Rapid City SD going west. It went up so I took my foot out and put the load at about 95% and it stayed there till I finish3ed the climb then it went down. We have to pull air and not push it and altitude makes a difference too.
One of the things I'd like on our little old all-mechanical Cummins 5.9 would be a Silverleaf display but the two are simply not compatible. I worry about high temps on long mountain grades (and we have plenty of both of those where we live). I see the engine water temp go over 200F and immediately start to get concerned... but I always wonder just how accurate that gauge is. My suspicions are that it's not very...
I think I'll see about setting up a way to monitor things a little more accurately using my Raspberry Pi and its ability to deal with the real world and then display that on a web page that I can get to with a smart phone or a tablet.
We really like our U225 because of its light weight, lower overall height, narrower footprint and excellent fuel mileage. Plus it's creature comforts inside. Not to mention the snappy performance (50mph or better at the end of every on-ramp we've used so far (except for serious up-the-hill ramps in the mtns).
No way to duplicate the Silverleaf's ability though. Maybe I can come close...
Craig
Craig, I thought I should share some of my experiences with our 1993, U225 regarding over heating. This was the first diesel I had ever owned. I noticed that in the hot Oklahoma summers, 95 degrees plus, the temp gauge frequently exceeded 200 degrees, even on small long hills. I asked the local Cummins dealer a number of times as well as the national Cummins Tech line and even one of their top tech people at an FMCA convetion what the maximum temp of the 5.9 should be. I got different answers from every one ranging from 185 to 225 degrees. I spent close to $2000 trying to cool down the coach and became obsessed with the temperature gauge while driving. I replace the radiator cap, which was bad, then had the radiator pulled and cleaned (it was in pristine condition when we got it apart), a new water pump, and thermostat installed with no noticeable change. Oh, I also bought a new temp gauge and sending unit from Foretravel to insure that the gauge was correct and verified that the gauge was correct. Nothing seemed to change. I did find that the temperature gauge read about 5 degrees higher when the headlights were on, I presume due to lower voltage to the gauge at the dash.
One day I accidentally turned on the heater while chugging up a hill and the temp gauge dropped 10 degrees. That prompted the idea of install another radiator behind the grill and A/C condenser and plum it into the heater return hose behind the heater core. This dropped the running temps by an average of 10 degrees during hot weather.
Finally after all of these efforts I read there was a Cumming Technical Bulletin regarding maximum temps for a Cummins 5.9 available. I followed the link and discovered that the B5.9 had a maximum running temperature of 240 degrees. Finally I had it in writing, a specific guideline on that engine but I never quite believed it and never got over my obsession with coolant temps. I watch my Silverleaf Temp on my U300 constantly.
I'm sure you will want to see tat Tech Bulletin, others have asked previously, but unbelievably I cannot find it on my computer. I have also tried to find a reference to it on the net and as before have not been able to locate it but I did see it with my very own eyes and yes I was sober. The following which is more believable was in my archives for the U225 but I don't recall the source.
Standard Modulating Thermostat - Range
B3.9, B4.5 and B5.9....................82 to 93°C [180 to 199°F]
B4.5 RGT....................88 to 97°C [190 to 207°F
Maximum Allowed Operating Temperature
B3.9, B4.5 and B5.9....................102°C [215°F]
B4.5 RGT....................107°C [225°F]
Minimum Recommended Operating Temperature....................71°C [160°F]
Minimum Recommended Pressure Cap....................48 kPa [7 psi]
Maximum Recommended Pressure Cap....................103 kPa [15 psi]
Never operate the engine without a thermostat. Without a thermostat, the coolant will not flow to the radiator and the engine will overheat.
The illustration identifies the significant features of the coolant system.
Sections A and B.
Coolant is drawn from the radiator by the integrally mounted water pump. The output from the water pump empties into the oil cooler cavity of the cylinder block.
The coolant then circulates around each cylinder and crosses the block to the fuel pump side of the engine.
1. Coolant Inlet
2. Pump Impeller
3. Coolant Flow Past Oil Cooler
4. Coolant Flow Past Cylinder Head
5. Coolant to Cylinder Head
Sections C and D.
Coolant then flows up into the cylinder head, crosses over the valve bridges, and down the exhaust manifold side of the engine to the integral thermostat housing.
As the coolant flows across the head toward the thermostat housing, it provides cooling for the injector. When the engine is below operating temperature, the thermostat is closed, and the coolant flow bypasses the radiator and goes to the water pump inlet through internal drillings in the block and cylinder head.
1. Coolant Flow from the Cylinder Head
2. Coolant to the Thermostat Housing
3. Coolant Flow Past Injector
4. Thermostat
5. Coolant Bypass Passage
6. Coolant Flow to Pump Inlet
7. Bypass Closed
8. Coolant Flow Back to Radiator
When operating temperature is reached, the thermostat opens, blocking the bypass passage to the water pump and opening the outlet to the radiator.
I hope this info gives you some solace and comfort and prevents you from wasting a lot of cash for nothing. To the best of my knowledge the B5.9 can run all day at 215 degrees, however I still would not be comfortable myself running that hot.
We had no alarms or lights but I certainly would rather choose the shutdown point and allow high idle versus the engine forcefully shutting down and cooking the turbo. It really wasn't rising past 210 but I suspect it could have. I think the gauge is pretty accurate. It will go right to 180 in the morning and sit there until I hit some kind of grade. Unless it's in the mid 90's then it will go to 185 maybe cruising flat 62mph 1400RPM. We were climibing the grade in 3rd gear, 1900 RPM. I haven't really seen much difference as far as keeping cool and which rpm but I suspect somewhere around 1700 works best for my coach.
We are very very heavy. We had a full front tank of water, 110gallons, we full time so we have all of our stuff. We have full fuel and our GX470 is probably an easy 5000 pounds. I am not complaining. My wife however was making fun of me saying we wouldn't have this problem towing a trailer with the Lexus. I can't wait to be on the side of the road with a coolant hose popped :-P
Also cummins documentation states 180-212 for the M11. That's why I killed it at 210. I try to do my best to keep the 15-20 coach bucks in my pocket ;)
Thanks for all the comments. You guys really put my mind at ease that our cooling system is in good shape.
Carol,
The load you read on your display is the injector potential load or what percentage of the maximum fuel the injectors are flowing compared with the maximum amount the computer will let them flow. For instance, at idle, my Pro-Link reads abut 25% load and goes up as the RPM and speed increases. The computer readout and the actual load will both be 100% at full throttle on a grade.
Bob,
There is a big difference between a dry sleeve 71 series Detroit and the wet sleeve 92 series. Dry sleeve engines have an advantage as they can take higher temperatures because there is no sealing ring(s) that can fail and let coolant into the crankcase. The disadvantage is heat transfer is not quite as good and overhauls are much more difficult to do a good job as careful measurements have to be taken before the liner is pressed into the block by a machine shop. With a 92 series, the liners are user replaceable with better sealing rings made today than when the 92 series first came out. With the DDEC and wet sleeves, overhauls are much less expensive and take far fewer hours than in the old 71 days. That is why the 92 engines are called "premium" engines by overhaul shops.
In researching marine forums on the 6V-92TA, the recommended alarm temperature is 195 degrees. The engine was super popular in sport fishermen as the V configuration allowed for lower decks than the inline engines plus the engine was able to produce more reliable horsepower per cubic inch than any other engine with 525HP the most common number and 625HP in some boats. Naturally, the more HP, the shorter the engine life is. My ex-greyhound had over 900,000 on the original 8V-71 before it was overhauled.
Engine life depends on HP and owner maintenance. Detroit 2 cycles used in generators running close to a full load frequently pass 40,000 hours before any maintenance is needed. The 60 series Detroit is history with only the 2 cycle 92 series and the DD13, 15 and 16 being manufactured by Mercedes (MTU) today.
Next time you see a train, chances are it's a EMD 710 2-cycle (16 cylinders, 710 cubic inches per cylinder) powering it. The most reliable, most economical locomotive diesel ever made. Detroit just took their smaller highway engines and oversized them with modern improvements like clutched turbos eliminating the big power robbing blower.
Piku,
You were wise to watch the gauges. I just shift down and slow down until the temperature stabilizes at or below factory recommendations. Running above recommended temps may not cause an immediate problem but can shorten engine life and may not show up for thousands of miles. Also, good to remember that even though the coolant temperature comes down fairly fast, the oil temperature will stay up for much longer. Failure to allow the oil to cool down can still cause the turbo to convert the oil to coke and cause turbo failure with the possibility of engine damage because of that. So, fast idle the engine for several minutes after the coolant temp is normal before shutting down. Damage from overheating will cost in the $15K-$20K range.
Kent,
You were sure on the right track with your heater discovery. Foretravel missed the boat with all that grill area up front.
Pierce
Piku,
You might want to check into your high/low switch on your fan motors. I installed a warning light on mine to tell me when high mode kicks in. I've found mine doesn't kick in until my gauge is reading close to 200˚. I've been told it should kick in around 190˚ to 195˚. It could be my gauge is off by a few degrees. I think I'm going to do what Dave Katsuki did and install a switch to manually activate high speed mode when I know I have a hill to climb. That way I can pre-cool everything down and have some reserve for the hill.
I've seen 2 types of high/low switches. Mine is controlled electronically via a solenoid where as others (Dave's) are controlled mechanically. I helped Dave install a solenoid on his (actually I just drove him around to several hydraulic shops as he gathered parts he did all of the dirty work :) ) to override the mechanical switch. He reported that he noticed a pretty big improvement in cooling on hills using it. He also promised to write up a tutorial on how to install one. I'm calling you out Dave! :)
When I get mine done I'll do a write up for electronic solenoid controlled high/low switches and report any improvements on cooling I see.
BTW on my coach I run in low speed mode > 90% of the time. Only on longer hills do I see high speed mode.
JMHO but at 210˚ I wouldn't be worrying too much. I would be gearing and slowing down to see if the needle would stay at 210˚. 215˚ I'd be looking for a place to pull over and cool down.
see ya
ken
I agree with the post concerning the U280 with Cat engine. My old 1990 U280 with 3208T and the rear mounted Atlas industrial all copper 4 tube radiator never gets over 190 degrees no matter how hard you run it. I expect that the cost of a new radiator like that would be about half the value of the coach today! I'm still getting to the variable temp I see on my newer U320.
All I know is that when the load is reduced on a long grade, the temperatures reduced, as well ... may not be the scientific interpretation ... but it worked!!
Pierce... thanks for repeating that. I had forgotten the 240F figure; you have quoted it before but I had forgotten what the number was. I am very tempted to do the same thing regarding the secondary cooler in the front. Did you mount yours in front of the A/C radiator? Not a lot of room up there but something would help.
Craig
When temps increase a lot during a long climb, the throttle is usually being pressed too much and the gear selected too high and the speedometer is reading too high a number.
We spend hundreds on trying to reduce coolant temps and found that slowing down a lot and driving in a lower gear completely solved our high heat problems. We also watch our boost to be sure it is working and keep an eye on our pyrometer to hold it below 1,000 degrees. One eye on pyrometer & the other eye ball on tachometer, with someone else looking out the windshield. We don't worry about running into the vehicle in front as we are often going too slow up mountains.
Craig,
That was Kent's post. While I'm installing my tankless block heater and exploring all the ways to run lines in the dark recesses of the coach. I am also figuring out how to run larger piping up to the nose for a couple of NASCAR type aluminum radiators right behind the grills. I would like to round file the whole hydraulic system and replace it with electric fans but there are not any that will do the job on just the existing side radiator. With a couple up front, I could go entirely electric and gain about 30 HP and some fuel mileage to boot. Every time I look at all the belts, pump, motors, shrouding back there, I get mad.
Lots of options on ebay for aluminum radiators and they are a tiny fraction of what Foretravel would charge for the OEM side or rear radiator. Easy to mount up front and they would take advantage of ram air going down the road. The heater hose is a little on the small size for moving coolant up front to a couple of good sized radiators so that is the reason for finding an alternative path to the front. No problem going through the any of the compartments. It's just the first few feet from the bulkhead to the wet compartment that poses a problem. I suppose I could go up into the closets and kitchen compartments and then back down but would be a lot of work. Was thinking about 1-1/2" ID piping. Our U300 has a lot of room up in the nose for any kind or number of radiators. Think two with a set of electric fans behind them would be perfect.
Yes, the AC condenser would have to be moved but we always run the generator and roof ACs while underway so not worried about it.
As it is, we can run flat out up the grades unless the ambient goes over about 85 or 90 degrees. Then I have to watch the gauge. We came up and out the steep side of Death Valley to Highway 395 pedal to metal all the time without going over 195 . Same way with I-80 and Donner Pass at 57 mph in third gear unless it's warm outside.
Pierce
Piku you did the correct thing by cooling it down although maybe you didn't need to, but why take a chance. The only thing I can add to this is that I found leaves on the radiator behind the charge air cooler. The side mounted radiator does require the fans to pull air through it, and being mounted behind the rear wheels it does pick up a lot of dirt that can cut efficiency.
Road crap between the CAC and Rad is caused by it being thrown up from duals and there should be some belting fastened under them to prevent this. I also put some more down both sides to sort of close the whole perimeter off so air has to come thru grille and CAC. I do not have any issues with heat while climbing the Grapevine etc but I also do not have tons of extra weight behind in the towed. My tracker is heavy enough to go shopping and sight seeing but does not cause coach any problems.
JohnH
I decided to bite the bullet and install a secondary cooler (a la Pierce) for the U225. There is room for a small unit up forward and I think a handy-dandy set of ball valves would make it easy to put on-line or take off-line. In fact, since summers here typically run in the high 80s and low 90s (with excursions above 100 more frequently) just leaving it in the circuit from June through August would not be an issue.
About $30 with tax from Amazon. Should work at least as well as turning on the heater.
Amazon.com: Hayden Automotive 402 Ultra-Cool Tube and Fin Transmission Cooler: (http://www.amazon.com/gp/product/B000C39C86/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1)
Craig
Craig,
Good idea, but I would use a real radiator up front, not a transmission cooler. And, as you suggest, use ball valves and the existing dash heater hoses to bring the coolant from engine to the front.
Before deciding to leave it open all the time, even in summer, I would see how much it delays reaching operating temperature from a cold startup. If no more than a few minutes, leave it open. But you DO what the engine to get up to operating temperature pretty quickly.
Cat, Cummins, DDC & Kubota teaches min water temp is controled by thermostat, not radiator size. Unless there has been a change in physics ?
Dave,
On a lot of engines, coolant goes directly from water pump/pre-thermostat to the dash heater lines. This gives faster heater warm up at the expense of slower engine warm up.
I second Brett's suggestion about using a real radiator. Tranny cooler won't do it. There are four small screws accessible from the outside to remove each grill. Measure for the size and then go to ebay for something that will match up. While the heater hoses are small, the lower flow rate through the aux radiator(s) will allow a larger drop in coolant temp. VW did that with the Vanagon with a flat washer with a hole placed in the supply pipe to restrict the flow through the front radiator. The aux radiator will need good ducting so ram air is forced through the radiator, not around it.
I installed a five cylinder Mercedes engine in a MBZ 309D van. The engine was too long and the front radiator would no longer fit so I fitted a large truck radiator flat behind the transmission. A little ducting and it worked fine.
Pierce
I guess I am lucky. In all the years that I owned FT diesels with a Cat 3208 and a Cummins 8.3 I never had overheat problems and I have traveled all the states with most of it in the west. I always found that on a long grade as engine temp started to climb that a down shift to lower gear and reduction in speed and increase in RPM maintained temps without a problem. I have been on grades in CO, WY, MT, UT, CA etc and never had one overheat on me.
AND I never felt like I had to be the first one to the top of the mountain.
Gary B
Makes sense for auto use, I always think industrial apps.
I agree with using a radiator, not a trans cooler. A trans cooler will greatly restrict the flow of the system unless it is installed as a loop. The radiator hoses on my U225 were 3/4". The inlet/outlets on the NASCAR 24" X 24" dual core aluminum radiator were only 5/8" so I had 3/4" I/O welded on. The flow from a 3/4" line is better than you think. I plumed it using a two "T"s and a ball valve. To take it out of the heater circuit I had only to reach under the front end and turn the handle stopping the flow to the radiator. As I recall the used radiator was under $200 from ebay.
On the U225 there was plenty of room behind the A/C condenser. I use our dash air and didn't want to sacrifice our air conditioning. The condenser did not have to be moved or even removed for installation of the new radiator. The whole installation took less than five hours. I made bracket out of 1 1/2" aluminum angle from the hardware store and used old inner tubes to prevent wear on the aluminum radiator from vibration. The hardest thing to find were the 3/4" Tees.
My local cummins shop foreman mentioned in passing that the normal two speed hydraulic cooling fans do not go into high until 210.
My 97 is variable speed.
Most of the specs are for trucks. We are 1/2 weight. M11 crosses into heavy duty engine series. G
All the radiators I found were LOTS bigger...
Craig
I figured that the trans cooler would be at least as good as the heater. It is already in a loop, right? I mean, when you shut the heater down there is no coolant flowing through it, right? Or do I misunderstand how this works?
Craig
I'm very skeptical that the dash heater or your added cooler have that much of an effect. I wonder, instead, if the return flow from the heater passes right over the temperature sender.
Making HP makes heat. Many car engines run "cool" around 205-215F. If it's holding steady around 210-215 and you are maxing out the HP, nothing is abnormal.
One would have to talk to the packaging engineer at FT to get all the facts, but I rekn' they design the required amount of heat removal to be just about that of full HP of the engine. This means, when you make more HP, the temperature will climb.
Remeber, RV's usually have increased HP ratings (recreational) from the commerical continuous duty ratings.
Yup, if youget BTU's/hour of heat transfer for the primary radiator (fan on high) and for a "supplemental" radiator, you could easily determine whether this was a fool's errand or a significant contributor to proper engine operating temperature.
I can tell you that from a practical standpoint, I have used the dash heater to maintain proper operating temperature on long hard pulls where I wanted to stay at peak torque RPM for lower fuel consumption. Sure, only when ambient temperature would not overheat the interior.
But, I have no problem using dash heater on the upgrade if the dash A/C can bring it back down on the downgrade. Did this more to prove a concept than to use as an every-day solution.
I am curious as to how much cooling capacity has been lost in the last 15 years. Has the radiator ever been professionally cleaned inside and out? Has the engine been flushed of scale and deposits? How much coolant flow has been lost due to age of the pump? Has the thermostat been replaced in 15 years?
While most of my experience is with air cooled aircraft engines, the principles are the same. When cooling capacity is slowly reduced over time, actual engine temperatures tend to remain constant until such time that enough capacity has been lost that the thermodynamic system bootstraps and you get significant temperature increases.
Had several customers install aux cooling on u225's. Front radiators with spray bars and one left and right in the drivers side engine compartment. Both helped. Always wondered about less slip in the torque converter?
This seems to be a common issue with U225s that are based in the west. Pierce had the issue, I have the issue and Bob (who was based in the west) noticed several others (presumably on coaches that were much newer at the time).
Judging from ads in various RV magazines, extra cooling is a common issue among DPs anyway.
Once you get to 400 and 500 (and 600!) hp engines with side radiators and big hydraulic fans the issue probably goes away. But the U225 had 230hp to begin with and even though ours has a Banks Stinger package (basically better turbo) the mountains in the west still might be more work than the guys in Texas thought it would ever encounter. Probably not that much of a big deal going from OH or NY to FL. But where I live it's not at all uncommon to go from 700-feet (the Columbia River at Vantage, WA) to 2400' in 10 miles and then another three big climbs and descents; all just to get to Yakima (100 miles).
Heck, I can remember pretty clearly when a lot of cars had this problem.
Craig
The solution, drop a gear and don't push as hard on the pedal.
Craig,
And I have noticed other U300 owners have also run a bit warm in hot weather. I slow/shift down but in summer, the endless grades on I-70 are frustrating. I have the twin large hydraulic fans and a spotless radiator and no, the issue does not go away as this post's topic originator, Piku has learned.
In driving a 7700 lb fully loaded horse trailer to Ohio in warm weather behind our 3000 lb Toyota RAV4, the temp gauge never moved even over Eisenhower Summit in first gear. So know a cooling system can be designed to have a huge reserve capacity. Ours is marginal at best.
If you mount a front radiator, you might consider a 12V pump (centrifugal only) to help the coolant back to the engine. High temp, 40 liters/min pumps are just under $100. Won't get that flow with friction loss in the hose but it will help. Probably mounted up front where the return hose heads back and powered off the hot side of the ignition solenoid with a switch in the line. I ran my HID headlights off the same terminal.
Pierce
If you extract maximum HP continuously out of a car like we do out of our engines on long climbs, it will probably increase in temperature as well.
Also, rear engine, side radiator vs a tractor trailer that has a massive front mount radiator...............they have tons of airflow that doesn't require HP robbing fans to pull.
The BEST solution from an effectiveness and efficiency stand point would be to mount the radiator up front...or have massive scoops on the side.
Designing machines is always about trade offs. Climbing mountains is what % of hours spent driving each year? Downshift, go 5-10mph slower.....
You have to figure that they designed it at the min spec for cummins not to intrude into the house part. The new coaches have much bigger cooling packages though and they do intrude. I think it would be a small price to pay.
You said it all! But why didn't they listen in the GVs? Look at all the room up front. There are already AC plumbing, fuel hoses, heater hoses, power steering hoses, electrical lines running forward so a couple more pipes would have not even been noticed.
Our 4107 had a huge side radiator with direct drive off the engine. Never even got warm. U300s still have 2Wx4Lx2H feet of wasted space in front of the muffler on the driver's side.
Pierce
New coaches also have much more HP, right?
When I was driving big rigs cross country I always put my radiator fan on high BEFORE I started the climb. I did have to turn off the air conditioner a couple times going up the grapevine in mid summer, but I never overheated. Did have the pedal to the metal, don't drive like that now no hurry.
Roland
yes and no. THe small ISX is not much more than the 500 ISM but they run hotter so I guess they need more cooling.
(just getting time to come up to speed on the forum again...)
And the effect of turning on the dash heat (coolant valve control) is exactly what causes our dash temp gauge reading to go down (1999, ISC engine). If you look at the placement of the sensor on an ISC, it's in the coolant loop that goes to the heater, and when there is no flow there, the radiated heat from the turbo will increase sensor temp dramatically.
On our coach, the original water heater had the engine coolant loop running through it, and I suspect that was enough to keep the sensor more accurate. When I had to replace the water heater several years ago, the only one I could get fast didn't have the engine heating loop, and dash temp started increasing dramatically under load. I only figured out what was happening after replacing the sensor and noticing the placement. Now I only go by the VMSpc reading.
And BTW - there is a shutoff valve in our water compartment that cuts off coolant flow to the water heater. If that's closed, there will be no flow past the sensor until the dash heater valve is opened.
It's coming! It's coming! Actually I was putting it off 'cause the coach has been sitting still all summer, so no more real experience with the manual control until we move next week.
We agree! The Silverleaf VMSpc has already been most useful, and already I wouldn't want to be without it.
@Dave From Jackson to Denver it's all downhill! Look forward to seeing you and Nancy next week.
see ya
ken
In my case, the radiator was replaced with a custom made aluminum unit ordered by a Cummins shop, Tampa, I think. Some of the rubber hoses were replaced, some where factory. I drained the coolant and replaced all of the heater hoses, both 3/4 and 1" going to the coolant box. I added a ball valve to stop the convective current the aquahot can sometimes get. I replaced the silicone couplers that connect from the steel coolant pipes going to the radiator as they were cracking. I replaced the rubber couplers that connect the transmission cooler to the metal pipes. The regulator, water pump and other pipes are stock. Coolant is Fleetguard ES Compleat OAT ethylene glycol. Cannot tell age/maintenance of the hydraulic system, fans, etc but they make a LOT of noise when they go on high speed mode and move a ton of air.I would have to put a tach on them to verify functionality though.
When I drained the coolant, the old coolant that came out looked perfect. Looking into the various holes exposed there were no signs of scale or corrosion. The radiator has no build up of leaves or debris but could probably use a cleaning.
I had a misting system on my Bus that when needed worked really well, pulling the grade up from Phoenix to sunset point rest area when my temps started to climb past the 195 mark I would give it about 15 to 20 sec of mist and held her steady. I'm considering putting one on this u300, have all the room i need with the two vents.
We too have a spray system, the "Ultra Desert Cooler" radiator spray system and it works very well. Regrettably, they are now out of business. The inventor passed away several years ago and I read his son has since ceased doing business.
The system would be fairly easy to replicate. The switching system is basically like an intermittent windshield wiper switch. It will activate a simple 12 V pump that squirts water on the surface of the radiator out of five "Star Type" plastic spray nozzles. It can be set to spray short burst of water once every 20 seconds down to every three seconds. It is plumbed to the inlet side of the main water pump. My pump is a low pressure Flojet pump. The only things that I don't know how to acquire is the spray nozzles. However I think a 3/8" or 1/2" PVC pipe as the cross beam with angled holes drilled into it or little mister heads screwed directly into the pipe might make it work.
Some people have mentioned concerns about using up the water from the fresh water tank but we only use it during the hot summer months on major and long inclines, seldom over 10 minutes at a time. I have never even noticed a change in the water gauge. I usually turn it on a mile or two before a long uphill and then adjust the frequency of the spray as we are climbing based on my VMSPC. The VMSPC reacts to temperature chance almost immediately and minutes before the on board coolant gauge.
If anyone is interested i will try to shoot some photos of my system and try to help them design a system.
Thanks Kent for that information, and yes I would love to see some pictures of your system. On my Eagle I had a valve that would supply fresh water out the bottom and I had my pump in the old battery compartment, I had a switch on the dash that i had marked as mister. It work very well and would like to see what you have .
Regards Andy
I used this on my 4905.
Outdoor 3 4GPH Fogging Mister System Patio Cooling 50' | eBay (http://www.ebay.com/itm/Outdoor-3-4GPH-Fogging-Mister-System-Patio-Cooling-50-/200657596749?pt=LH_DefaultDomain_0&hash=item2eb81ff14d)
RE: The only things that I don't know how to acquire is the spray nozzles.
Kent, there are many home/business Misting Systems and parts out there:
Brass Nozzles - Brass Series Nozzles 10/24 - Mist Nozzles - Patio Misting (http://www.aeromist.com/mist-nozzles/brass-series-nozzles/brass-nozzles.html)
Thanks Gents for the information.
Plumbing stores have the nozzles in stock. Ebay also. Make sure to get the variety with the tiny filter attached if possible. Schedule 40 half or three quarters inch x 1/8" fittings are also stocked for the brass or plastic nozzle to screw into. Also a good idea to buy the filter to get rid of the calcium so you don't get the white deposits on the radiator. Vinegar with get rid of them if you do. Kent's pump is a good one. Lots of info online with google search.
Pierce
The ultra desert cooler worked well
After giving this further thought I would not use the "mister" nozzles. They can corrode and clog very easily with regular tap water. My commercial unit does not mist but spray small streams on the radiator in a star pattern. The nozzles are about 10" apart.
I think if one were to use a 1/2" PVC pipe the full horizontal length of the radiator and simply drill small holes at different angles to cover more of the radiators surface you would have a workable and more reliable system than by using misting nozzles. The misters might be more efficient but clogging would be problematic. It would just take some experimentation but I'm guessing 10 holes per foot is the right amount, one hole spraying center, the next spraying up and the third down. The more holes used the more water used but I know it doesn't take much to cool the radiator.
One might check the IRV2 archives for the Ultra Desert Cooler details.
Good luck.
Done - Manual fan speed control for our 99 U270 (http://www.foreforums.com/index.php?topic=22584.new#new)
I think there are also issues of calcium deposits accumulating on radiator fins over time. And in our side flow radiator, the front of the radiator is not accessible as the intercooler is just behind the slats. Even if water flow PVC pipes can be installed in front of our radiator, later cleaning off any accumulating deposits would be impossible without removing intercooler. Also wonder if there are other down sides to flowing water, like rusting, etc. Misting works to cool radiator, but may bring its own issues.
How many gallons per hour are we looking at here?
Been thing through this and certainly not as versed as Pierce and other gearheads ^.^d
I would think that if water is a concern then too much water too often is "misted"
I would think that a long pull of 4 miles would take less than 10 minutes at a 5gpm rate would be less than a 1/2 gallon and isn't the purpose to "evaporate" against a hot fin?
That provides the cooling, right? If it is constantly wet then the temp of the water will be closer to the radiator temp and will not cool as effectively as evaporation.
The "water deposits" seem to occur over prolonged use, not 10 minutes every 4-5 hours someone would be climbing through 3-400 miles of mountains. :o
Am I looking at this wrong?
Just looking at the KISS of it. Seems if downshifting, taking your foot out of it generally solves any issue.
Do big trucks have these systems too, or just Camping world?
Down shifting and keeping your foot out of it will give you the best results, However during those times when it is needed a cooling system works well. The 2 cycle in our case the 6V92 TA can be sensitive to heat and if not careful you can smoke the engine. Having owned a Bus with a big 8V92 I was always aware of what was going on with my temps. And I agree with the KISS method myself. ;D Most Heavy truck do not have these systems, but they also have Huge radiators and the air flow is coming directly at them with big fans ^.^d
Big trucks also don't have a 4-speed automatic gearbox....
Craig
My bus had a side radiator about twice the size of the U300 with one direct drive fan. Our later 4 speed automatics lock up half way through second gear so don't add any heat. They sure do around town and the big heat exchanger quickly loads the engine cooling system on a hot day.
Pierce
Driving with the windows open, I can hear the high/low fan speed. Somehow there seems to be three speeds but maybe not. If I start the engine cold, the fans will run on an obviously low setting. If I set it on high idle sometime around when it warms up to 180 on the gauge the fans spin faster. It seems to stay this way until I shut it off. This was in 70 degree weather. The other day however, driving down the road I could hear the fans spinning faster and slower alternating. The gauge was sitting right at 180.
So I don't know about high mode kicking on at 200 or 195 for me. It seems to kick into high much lower than that.
Since the radiator fan motors are hydraulic powered, they turn faster, when hydraulic pump turns faster with higher engine RPM's.
Barry,
I recently purchased a Cen-tech tachometer like yours and checked my fan speed since after reconnecting the fan switch I found disconnected by the PO. I have the the twin fan setup on the the side radiator. The results were:
62 rpms at idle... 600 rpms
155 rpms at fast idle... 1000rpms
755 rpms at 1000 rpms with fan switch disconnected (default setting)
I don't know if this is normal, but at hi-speed both fans pull a lot of air through the radiator. It's never run higher than 185 even when heat index here was 100+, but I also live in flat land. I have a pro-link to check the coolant temp vs the dash gauge. Only about 3 or 4 degrees difference between the two. Have you checked to see what your fan speeds are? I'm sure James Triana will know what normal is.
Jerry
The Detroit 2 stroke engines DO require more radiator than the 4 stroke engines, in my experience, only needed the added cooling with the Detroit engines, my ISM500 does not need it YET. Last summer was in Co/Mt with the toad/F150 & large ATV, no temp issues when outside temp in the 100 area. Seems the standard Foretravel radiator works well for me so far.
Dave, I never had an issue with my 36 foot either. I do runn a bit warmer up the same grades with the 42 foot. I think we have the same radiator so that is to be expected.
When I say faster I meant for a given stable engine RPM.
Just learning- how do you back off to "95% load"?
Also what to you mean by "downshifting and keeping your foot out of it"?
Thanks in advance,
Learned how to handle a big climb and mountain driving from John S. Going up I keep the RPMs around 1500. When they get to 1400 I down shift back to 1500. Never got below 3rd gear. Coming down the other side use the same gears going down as coming up. Use the retarder some but keep off as must as possible. Remember your tow is pushing going down so use your brake to activate the brake in the tow to help with the decline. Take your time. If others want to go by let them go you are not in a race. You will arrive about the same time as they do anyway. The retarder will still be your best friend. Your temp will go to 190 or 195 but no higher. Thats right // keep your foot off the gas pedal. Don't press going up, let the coach ease up the speed. tks DAN
Don't know who you are asking, but both make perfect sense to me (ya 200,000+ DP miles are a great teacher).
Downshift means just that. Downshift to a lower gear were there will be more engine RPM for a given road speed.
And, at higher RPM, the water pump and fan are turning faster for roughly the same heat load (XX HP required to push YY pounds up ZZ grade).
And, at higher RPM there is more HP, so you can back out of the throttle without loosing speed. Sure, there is a down side-- you WILL use more fuel. So conserve fuel, but only if you are not overheating the engine and shortening it's life.
Brett, that makes sense, rather than "gut" the engine. I've been shifting down and my 3208 likes 2000-2200 RPM. At 1800 RPM I'm slowing down fast with no power. Sweet spot is about 2200 RPM.
As suggested, I do keep it about the same RPM and gears going down the other side- no problem letting the world go by.
I don't seem to have engine go much over the 190 area on a grade, but the transmission will come right up- normally barely registers. I've only had this issue on two grades- the earlier mentioned one in Rapid City, SD and coming north on 65 out of Clinton AR heading north to Branson. Both forever long grades with stoplights dead at the bottom :(
I have the 4 spd 643 Transmission- no retarder.
The "95% load" was from one of the first posts on page one- it may be related to computer readout of some type?
Thanks, as I said, just trying to learn!
Did route 88 over the Sierra Nevada's today. Temperature management wasn't too tough but we ran most of it in 3rd gear at 35mph. I could have gone faster but the twisties were just a bit too aggressive to be going that fast. I only got honked at once :-P
Do any of you guys have noticeable gaps between the fan shroud and the radiator and the radiator and the charge cooler? Cummins replaced our radiator and we have some pretty big gaps. I feel that finding some way to baffle those in will improve cooling performance greatly.
RE: noticeable gaps between the fan shroud
Gaps around radiator shroud allow warm air from inside engine area to recirculate through radiator, reducing cooling capacity. VERY important to seal all the gaps in the conveyer-belt type material. Best cooling occurs when only outside air goes through radiator
We use spray-foam in all gaps on sides and bottom, then paint the foam black. We did make bottom drain holes in bottom to allow water from rain or washing out with a hose to drain out.
Agree on what Barry said re- gaps.
I did that a few years ago but used belting cut to fit tight around fittings and joined to bottom peice with sheet metal angle and screws. Air has to go thru side grille then CAC as no other way in now.
I have also stopped all splash from Duals as this IMHO is the way road garbage gets between the units and causes some of the overheating.
JohnH