OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Topic: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE (Read 3718 times) previous topic - next topic

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #25 – May 24, 2012, 11:44:52 am

my VDO guages in my 1999 U-270 were notoriously innacurate, drove me to a silverleaf solution. On the 2000 they seem perfect. Wonder if you have a gauge issue.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #26 – May 24, 2012, 05:15:10 pm

All good points, but I am wondering if your hydraulic fans are turning up to speed, I can not guess what would be wrong with that setup with a 8.3, clean fins, fresh antifreeze, new thermostat and new belts, leaves me thinking fan speed.
Good luck
Dave M

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #27 – May 24, 2012, 05:19:18 pm

As Dave suggests, if the fan is not kicking to high speed, THAT could cause your problem in high ambient temperatures or high loads.

Have you verified that the fan controller is functioning properly?

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #28 – May 24, 2012, 05:22:18 pm

I've got a wiring problem with the dash gauge. It jumps from 180 or so up to being pegged on high. If I tap it it will drop down somewhere around 220 or 230. I've fiddled with the wires and know that one is not making good contact. I think I need to take the guage out and re-do the wiring. An Allison tech was doing a road test on the coach and paniced when the temp seemed to jump on the engine. My question is...how is the trans temp guage working. If it's in the proper range when the engine temp seems to be high then check the wiring, sender, or guage.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #29 – May 24, 2012, 10:42:16 pm

Thanks for the replies. I don't feel it is the gauges because the temp seems to climb and cool in a normal fashion. I probably confused the issue by saying it changed suddenly, by that I mean it dropped within about five minutes or so.
Brett and Dave, on the speed of the fan, its turning but how can I determine if it is fast enough?
Also, can you tell me the type or name of the water pipes that are used on the house water lines, I think I read in one of the past posts you can get this at Lowes. I need to patch it if possible, luckily it is in a spot I can reach. Thanks for all the help.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #30 – May 24, 2012, 11:25:50 pm

Lots of good replies and information! Just want to pass on an experience I had like yours with a sob coach some years ago, same engine as yours. Like you, climbing a mountain, downshifted and turning around 2000 RPM, overheated. Took it to a Cummins dealer for a check up and described what had happened. After finding nothing wrong, they said, try to stay close to the maximum TORQUE RPM for your engine, around 1500, when under a heavy load. Barry and Cindy had it right with their post. Downshift as needed, use partial throttle if necessary to stay close to the peak torque rpm, NOT the rated horsepower rpm. Worked for me! Using that technique, I have (knock on wood) never had another overheat on any of my RV's. That is not to say that you could not have a partially blocked section of the radiator, or some other problem. But if nothing is found, try this.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #31 – May 25, 2012, 12:37:25 am

On the C-8.3 Cummins engine, at what RPM is the max torque? And what is the max hp RPM?

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #32 – May 25, 2012, 08:40:43 am

Quote from: newal – May 24, 2012, 11:25:50 pm

Lots of good replies and information! Just want to pass on an experience I had like yours with a sob coach some years ago, same engine as yours. Like you, climbing a mountain, downshifted and turning around 2000 RPM, overheated. Took it to a Cummins dealer for a check up and described what had happened. After finding nothing wrong, they said, try to stay close to the maximum TORQUE RPM for your engine, around 1500, when under a heavy load. Barry and Cindy had it right with their post. Downshift as needed, use partial throttle if necessary to stay close to the peak torque rpm, NOT the rated horsepower rpm. Worked for me! Using that technique, I have (knock on wood) never had another overheat on any of my RV's. That is not to say that you could not have a partially blocked section of the radiator, or some other problem. But if nothing is found, try this.

Actually, that is not correct.

It takes XX HP to climb a grade-- irrespective of what gear you are in to produce that HP.

If you produce that HP at higher RPM (closer to peak HP RPM-- and at lighter throttle, as you have more HP higher in the RPM range), the water pump is turning faster, sending more coolant to and from the radiator, fan speed is higher as well. Lower RPM (i.e. peak torque RPM) gives less engine cooling for the same HP production.

Yes, it is more economical to climb (and run) closer to peak torque RPM, but if overheating, gear down, back out of the throttle and continue at higher RPM.

Brett

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #33 – May 25, 2012, 08:53:34 am

Quote from: Barry & Cindy – May 25, 2012, 12:37:25 am

On the C-8.3 Cummins engine, at what RPM is the max torque? And what is the max hp RPM?

I'd really like to know this also.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #34 – May 25, 2012, 09:17:15 am

Depending on the year model, EPA spec's etc, generally Peak Torque is about 1200-1300 rpm and Peak HP will be in the 1800 to 2100 rpm range.
Best dig into your engine manual specs and find the info for your engine.

Dave M

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #35 – May 25, 2012, 09:20:30 am

When I had my 8.3 I would hit the hills and keep the RPMs about 2100. Worked very well for hills or mountains and high ambient temps.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #36 – May 25, 2012, 09:57:59 am

What Brett says makes sense with any engine, when you start to LUG down the engine you raise engine temps considerably.
Gary B

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #37 – May 25, 2012, 02:30:17 pm

Here is the spec sheet that was in my manual for the ISC 350. Hopefully you all can read it ok.

Mark Z

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #38 – May 25, 2012, 03:04:54 pm

That sheet shows peak torque of 1050 at 1400 RPM and peak HP at 2000 RPM

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #39 – May 25, 2012, 03:22:45 pm

Brett is certainly correct. The waterpump pumps more coolant the faster the engine turns.

But considering you had been working on the radiator, my bet is that you did have an air bubble in the system. This happened to my once before and scared the heck out of me. I never saw it again.

Also I learned something new at Foretravel last week. Most Foretravels have a two speed hydraulic fan regulator. The high speed kicks in at 190 or 195 degrees if all is working properly. But my coach has a relative rpm regulator. The higher the RPMs the faster the fan blades turn. The fans run from 1050 rpm at idle to 1700 rpm at 2100 rpm engine speed. No one seems to know why they used this type of regulator on some coaches and not others. It still has the little electric switch but that switch is not hooked up to anything.

Fan speed is determined by a hand held tachometer. You put a piece of silver reflective tape on a fan blade or the hub if possible and point the tac at the area. It will see the reflected light of the tac gun and calculate the rpms.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #40 – May 25, 2012, 11:52:48 pm

This is really an interesting thread as 24 years ago and now I have been able to compare hp and torque of various diesel engines.

I go back to triple nickle front engine diesel non turboed cummins v8 to my current m11 celect plus 450...,

Unbeleivable transition for me. From the underpowered but revvy v8 cummins 555 front engine diesel to the 661 cu inch inline long stroke 6. Finally enough inches to torque up hills and keep the rpms low enough for decent gas mileage.

Let me give an example. I talked to my old buddy roger from foretravel of California days and mentioned that the 87 grand villa 300 cat ataac 20,000 pound 36 foot sbi got 10 mpg at 70 mph. 8 at 90. Yes,that's a real number over a 1,000 mile run. 3,000 rpm at 90mph. Fun fast. Tiny coach now that I compare it to my 97 320....

And my 320 gets 10 mpg at 65, 8 at 75+. Not bad for 33,000 pounds with a tow car.

The 8.3 needs the fuel pump turned up. Had a customer I sold a country coach 36 with an 300 hp 8.3 come back and show me the coach at 409 hp. Before you ask, the Allison man signed off the change in power for the trans warranty as the weight loading was way less than the 45,000 pound max weight rating for a 3060.

Fun fast to drive as I took it out on a test drive. 6% grades at speed. Left lane coach in the Rockies with no tow car. Car fast.... Remember I told you!

Been thinking about that ever since. Subject to enough radiator from foretravel all the older 300 8.3's can be turned up a lot.

If I had one it would be turned up for sure. Subject to radiator. Marine specs on power require the ocean for cooling.

I have driven 8v92's at 700hp and the prototype unicoach series 60 Detroit at 600hp+ so I am a jaded tourist

The massive 11 liter m11 requires patience. Way more torque than hp. A 300 cat had 743 pound feet of torque versus my m11 at 450 and 1450.

I sold Monaco 444hp 14 liter cummins with 1850 pound feet of torque. eaton 9 speed trans. Used 3-9. Crazy fast. 80 plus easily up steep grades. You had to lift your foot. Think about it. More power than hill and coach...Same as the 300 cat ored.

I knew then that the bigger engine was the fix. And an xtarder. Wow. A beaver 3176 and the L10 cummins and of course the m14 all had decent jake brakes but the trans xtarder takes the cake. 13% grade and did not need the service brakes.

I have gone from 318 dodge .travco' to 413 to 454 to 460 to 555 to 8.2 to 10.3 to 5.9 to 8.3 to 8.9 to 10.9 and lots more not mentioned. What a trip. You guys and girls are lucky. I have an ear to ear grin driving the u320 m11.

Bob

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #41 – May 26, 2012, 01:37:56 am

Well, lots of response to my post, including Brett Wolfe, who I consider to be a real guru and have learned much from his posts! My post was not intended to be a technical review, but an anecdotal experience. Brett, yes, the water pump is pumping more coolant at high RPM, but is the coolant able to absorb significantly more heat at the higher flow rate? And, is the radiator able to expel this heat? I think your conclusion is close to mine, except you recommend using the higher RPM. If you find yourself climbing a grade and overheating, I would say, back off the throttle, downshift, maintain about 75% throttle and try to keep the RPM at peak torque, -0+250 RPM by down or up shifting. When the engine is making less power (but more torque), it is making less heat. This is a matter of balancing the heat production with heat dissipation, while maintaining enough power to continue moving ahead. By the way, if you find yourself climbing a grade and not overheating, keep going! Also, this is anecdotal to operating 5 coaches over a lot of years. This is for those who do have a problem!

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #42 – May 26, 2012, 02:34:25 am

Quote from: newal – May 26, 2012, 01:37:56 am

Well, lots of response to my post, including Brett Wolfe, who I consider to be a real guru and have learned much from his posts! My post was not intended to be a technical review, but an anecdotal experience. Brett, yes, the water pump is pumping more coolant at high RPM, but is the coolant able to absorb significantly more heat at the higher flow rate? And, is the radiator able to expel this heat? I think your conclusion is close to mine, except you recommend using the higher RPM. If you find yourself climbing a grade and overheating, I would say, back off the throttle, downshift, maintain about 75% throttle and try to keep the RPM at peak torque, -0+250 RPM by down or up shifting. When the engine is making less power (but more torque), it is making less heat. This is a matter of balancing the heat production with heat dissipation, while maintaining enough power to continue moving ahead. By the way, if you find yourself climbing a grade and not overheating, keep going! Also, this is anecdotal to operating 5 coaches over a lot of years. This is for those who do have a problem!

Reminds me of a delivery up 17mile grade out of baker, ca. Delivering a 6v92 350 hp to the lippencott up the hill at 102 degrees. Out of state deliver. Still owned by foretravel until the deliver occurs in Las Vegas. I held the throttle floored up he hill while the customer watched over my shoulder. Never got past 240. Boil over is 265. Have any of you lost antifreeze? I remember a new Monaco with an L10 and split radiators that actually spit antifreeze out of the so cal desert in the summer run hard.

I had many customers leaving the desert in the summer at dawn to avoid the temp gauge moving much. Waste of time. No cooling system in an Rv does not get to 230 or more used hard.

Not like your car where the gauge never moves. 100 deliveries. Told every one to drive it harder. If the engine temp goes past 230 or 240 and continues to climb then back off and down shift.

Every owner was paranoid if the temp gauges moved. Normal. I tested this on foretravels money many times.

Bob

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #43 – May 26, 2012, 08:34:18 am

I did a Banks Kit in my 93 36 foot 280 with MT 647 four speed, then replaced the intercooler with one for a U320. Huge difference and a tiny mileage bump. Absolute ball to drive. Probably would have been even better with a dyno tune.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #44 – May 26, 2012, 09:46:38 am

Quote from: Caflashbob – May 26, 2012, 02:34:25 am

I had many customers leaving the desert in the summer at dawn to avoid the temp gauge moving much. Waste of time. No cooling system in an Rv does not get to 230 or more used hard.

Not like your car where the gauge never moves. 100 deliveries. Told every one to drive it harder. If the engine temp goes past 230 or 240 and continues to climb then back off and down shift.

Bob

Bob, everything I have read about the 6V92 has said letting it run over 210 degrees can result in real problems. Now I hear from you and Wayne Musser at Foretravel that the area of concern is really 230 to 240. I guess the correct answer is to take the conservative approach and keep it cool but I sure would be much more relaxed when traveling knowing for sure that higher temps in the Hot Hot summer were OK and not harmful. Is the 230/240 limit your opinion or is there something official from Detroit that can make me more comfortable.

Sorry about busting the thread but I have this thing about engine temperature.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #45 – May 26, 2012, 10:13:47 am

Kent,

You are correct. In fact, I would not run any engine over 210 without taking some measures to mitigate temperature rise.

Above 220 and you get into the "what can I get away with", rather than "what is best for engine longevity".

Brett

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #46 – May 26, 2012, 11:09:11 am

Quote from: wolfe10 – May 26, 2012, 10:13:47 am

Kent,

You are correct. In fact, I would not run any engine over 210 without taking some measures to mitigate temperature rise.

Above 220 and you get into the "what can I get away with", rather than "what is best for engine longevity".

Brett

I don't have the same engine but my "Stop Engine" light comes on at 212 degrees.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #47 – May 26, 2012, 11:36:14 am

I thought I had posted. Sorry if this is duplicate. I have a Monaco executive with a c8.3-300 Cummins. I spent in the past two years $25,000 on engine failure do to overheating. The cause was a radiator hose on the suction side of the system right behind the water pump. This hose should have support spring in it to prevent the hose from collapsing during times when max cooling would be needed, but in my case someone removed the spring. I could drive the coach with temps in the 90s and all was fine, go up a hill and the hose would restrict and my temps would go from 180 to 220 in minutes. My check gauge idiot light comes on at 220 degrees. You can see the pictures by going to YouTube.com and doing a search for "hinton's cummins hose".

Steve Bossier City,La

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #48 – May 26, 2012, 02:40:10 pm

Quote from: Kent Speers – May 26, 2012, 09:46:38 am

Bob, everything I have read about the 6V92 has said letting it run over 210 degrees can result in real problems. Now I hear from you and Wayne Musser at Foretravel that the area of concern is really 230 to 240. I guess the correct answer is to take the conservative approach and keep it cool but I sure would be much more relaxed when traveling knowing for sure that higher temps in the Hot Hot summer were OK and not harmful. Is the 230/240 limit your opinion or is there something official from Detroit that can make me more comfortable.

Sorry about busting the thread but I have this thing about engine temperature.

I had lots of discussions with customers and truckers and service people and my customers and my testing showed no adverse effect when in 100 degree plus weather and pulling a long grade to have the engine run up to the 240 range. As long as it stops there.

I have had a large number of these conversations with motorhome owners paranoid about the temp gauge moving at all. They left in the middle of the night to avoid the needle moving.

Same hill three months before with the outside temp at 70degrees the temp gauge says 210. Add 30 degrees ambient and 240 is the result. No coolant loss

The garbage guys laughed as their engines run 230 plus for hours in use in the desert and the trans ran 250-275 continuously.

Every motorhome owner is too paranoid about the temp gauge IMO. I ran all these really hard for hours myself to test them as they were my demos and owned by foretravel and the other companies and never had a single issue and neither did any of the customers I ever educated. Like I said if it runs 210 up a hill at 70 degrees and 240 at 100 degrees it's relative and within the design limits of the coach. Must have shown several dozen customers this up baker grade in the summer versus they baby the coach or really change their lifestyles to avoid ANY heating.

Took me a while as sales manager to finally have enough customers mention leaving at dawn because of the temp gauge moving to finally test this myself and ask oshkosh and the gillig guy and the cat man and the Detroit man and the cummins man and they all said no problem. Customers would watch as the gauge hit 240 and stopped. All be darned they all said.

If the system is in proper condition with good antifreeze and the changes in the temp gauge changes exactly the same as the ambient in the summer it's my experience that its fine.

My advantage was to be able to run duplicate or the same coach up the same grades at different times of the year and watch the gauges closely on the companies dime.

I actually videoed the drive up the grades with the old vcr equipment with the big box for the recorder and a seperate camera. Got them from dick and sue wells.

Showed how fast a 300 ored would climb the grades and showed the temp gauges stopped short of coolant loss. Easier to show a video of a demo ride than to drive a hundred miles but have done both.

Customer did not believe a 300 ored got ten mpg so we went 179 miles on 17.1 gallons and he bought a new coach. He filled the tank at the beginning and the end and Chet drove the coach. And let it idle a lot.

If the same coach up the same hill temp gauge changes exactly the same as the ambient I would think that nothing's wrong.

Every customer was paranoid enough for me to do the homework and testing as it did not sound right. Cars run 217 or more. No gauge. Idiot light so you do not panic

I went rving on my days off with the used coaches in my inventory. Then I fixed the things wrong and the next customers got a better condition coach. Better for them better for the store.

Same as my u320 that has a laundry list of needed items. Normal. Previous customers did not notice or use it hard enough to show or did not know something was abnormal. I did. They did not.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #49 – May 26, 2012, 03:08:24 pm

With many years experience with the DD engines, I see the 240f temps as one of many reasons Foretravel went broke, nothing like a salesman to help sink you.
No one runs a DD into that temp range without it getting shut down by the DDEC system.
Just one more reason for all the humor.
Dave M

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