Overheat on Long Grade

Topic: Overheat on Long Grade (Read 2839 times) previous topic - next topic

Re: Overheat on Long Grade

Reply #50 – September 24, 2014, 12:32:50 am

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.

Re: Overheat on Long Grade

Reply #51 – September 24, 2014, 11:56:45 am

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.

Re: Overheat on Long Grade

Reply #52 – September 24, 2014, 06:19:22 pm

Quote from: Andy 2 – September 24, 2014, 11:56:45 am

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.

Re: Overheat on Long Grade

Reply #53 – September 24, 2014, 06:57:53 pm

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

Re: Overheat on Long Grade

Reply #54 – September 24, 2014, 07:09:14 pm

I used this on my 4905.
Outdoor 3 4GPH Fogging Mister System Patio Cooling 50' | eBay

Re: Overheat on Long Grade

Reply #55 – September 24, 2014, 07:09:38 pm

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

Re: Overheat on Long Grade

Reply #56 – September 24, 2014, 07:16:48 pm

Thanks Gents for the information.

Re: Overheat on Long Grade

Reply #57 – September 24, 2014, 08:00:52 pm

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

Re: Overheat on Long Grade

Reply #58 – September 25, 2014, 12:16:23 am

The ultra desert cooler worked well

Re: Overheat on Long Grade

Reply #59 – September 25, 2014, 04:10:25 pm

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.

Re: Overheat on Long Grade

Reply #60 – September 26, 2014, 02:01:40 am

Quote from: kenhat – September 21, 2014, 12:50:00 pm

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!

Done - Manual fan speed control for our 99 U270

Re: Overheat on Long Grade

Reply #61 – September 26, 2014, 10:13:23 am

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.

Re: Overheat on Long Grade

Reply #62 – September 26, 2014, 12:00:06 pm

How many gallons per hour are we looking at here?

Been thing through this and certainly not as versed as Pierce and other gearheads

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.

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?

Re: Overheat on Long Grade

Reply #63 – September 26, 2014, 12:12:45 pm

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.

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

Re: Overheat on Long Grade

Reply #64 – September 26, 2014, 12:24:12 pm

Big trucks also don't have a 4-speed automatic gearbox....

Craig

Re: Overheat on Long Grade

Reply #65 – September 26, 2014, 01:15:23 pm

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

Re: Overheat on Long Grade

Reply #66 – September 30, 2014, 01:16:43 am

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.

Re: Overheat on Long Grade

Reply #67 – September 30, 2014, 10:12:03 pm

Since the radiator fan motors are hydraulic powered, they turn faster, when hydraulic pump turns faster with higher engine RPM's.

Re: Overheat on Long Grade

Reply #68 – September 30, 2014, 11:50:15 pm

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

Re: Overheat on Long Grade

Reply #69 – October 01, 2014, 01:19:07 am

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.

Re: Overheat on Long Grade

Reply #70 – October 01, 2014, 09:47:15 am

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.

Re: Overheat on Long Grade

Reply #71 – October 09, 2014, 01:41:19 am

Quote from: Barry & Cindy – September 30, 2014, 10:12:03 pm

Since the radiator fan motors are hydraulic powered, they turn faster, when hydraulic pump turns faster with higher engine RPM's.

When I say faster I meant for a given stable engine RPM.

Re: Overheat on Long Grade

Reply #72 – October 09, 2014, 09:17:55 pm

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,

Re: Overheat on Long Grade

Reply #73 – October 09, 2014, 10:20:33 pm

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

Re: Overheat on Long Grade

Reply #74 – October 09, 2014, 10:24:54 pm

Quote from: WC7610 – October 09, 2014, 09:17:55 pm

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,

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.

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