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KOALAVA · 11-19-2006, 04:44 PM

Looking for some input before I take it in for the check up. During a recent trip out west (back in September) from Virginia, we took the southern route (I-10)towards Arizona. During the drive across I-10 there were a couple of times when I noticed that the engine was running a little warm. Chalking this up to the high temp's in the region, I thought little of it. After arriving in Arizona we headed north and into the mountains. It was during one of the climbs (about a 5 to 6 percent grade) that the engine started getting hot. It got so hot that the temp gauge pegged out and the alarm when off. Of course I pulled over to the side and let the engine cool down and proceeded on. This occured a couple of times during the trip. while pulling hills even on the Interstate the engine ran hotter than normal but never got as hot as it did when pulling the hills a slower speeds. Of course I tried to take into consideration that the outside temp was into the 90's and above and when we did get a chance to go down hill the engine did cool back down. We have the 05 Kountry Star with a 330 Cummins ISL/ISC (28000 lbs) and were pulling a CJ Jeep (about 3300 lbs). When I got back I taked to a couple of guy's about that over heating issue and they said that it would get hot but it shouldn't have pegged out (with the alarm). Before I go in and have a check up done to it, I was wondering if any of you have had similiar problems and what was done to fix the issue. Be advise that prior to the trip all fluids were changed and antifreeze was good. Thanks
Harry

KOALAVA · 11-19-2006, 04:44 PM

Looking for some input before I take it in for the check up. During a recent trip out west (back in September) from Virginia, we took the southern route (I-10)towards Arizona. During the drive across I-10 there were a couple of times when I noticed that the engine was running a little warm. Chalking this up to the high temp's in the region, I thought little of it. After arriving in Arizona we headed north and into the mountains. It was during one of the climbs (about a 5 to 6 percent grade) that the engine started getting hot. It got so hot that the temp gauge pegged out and the alarm when off. Of course I pulled over to the side and let the engine cool down and proceeded on. This occured a couple of times during the trip. while pulling hills even on the Interstate the engine ran hotter than normal but never got as hot as it did when pulling the hills a slower speeds. Of course I tried to take into consideration that the outside temp was into the 90's and above and when we did get a chance to go down hill the engine did cool back down. We have the 05 Kountry Star with a 330 Cummins ISL/ISC (28000 lbs) and were pulling a CJ Jeep (about 3300 lbs). When I got back I taked to a couple of guy's about that over heating issue and they said that it would get hot but it shouldn't have pegged out (with the alarm). Before I go in and have a check up done to it, I was wondering if any of you have had similiar problems and what was done to fix the issue. Be advise that prior to the trip all fluids were changed and antifreeze was good. Thanks
Harry

Tom and Patty · 11-19-2006, 05:58 PM

What rpm were you running when climbing the hill?

I've been told and now practice running 1800 to 2000 when pulling a long grade. One reason this helps is that at a higher, the turbo is not adding as much boost. Less boost equals less heat. For us with side radiators, our fans turn at higher RPM's also.

KOALAVA · 11-19-2006, 06:05 PM

Thanks Tom, yeah I actually manually shift the Allison transmission when in hilly areas. I keep the RPMS up and never lug the engine. I was running the rpms around 1500 to 1800. Once the rpms drop to about 1200 to 1500 I shift down.
When going down hill or picking up momentum and the rpms reach 2000 I shift up. I was wondering if the altitude may have had some impact as well. We were over 6000 feet in some areas and being from Virginia (sea level)I wasn't sure if that may have played a part in it as well. Thanks for the input.
Harry

RV Wizard · 11-19-2006, 11:31 PM

If you have a rear radiator, check to see that it is clean. They tend to clog up faster than a side radiator. Too, are you hanging a rock guard on the rear?

KOALAVA · 11-20-2006, 07:25 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RV Wizard:
If you have a rear radiator, check to see that it is clean. They tend to clog up faster than a side radiator. Too, are you hanging a rock guard on the rear? </div></BLOCKQUOTE>

Yes Mike, I have the rear radiator and the rock guard. I did check the radiator when I got back by putting a drop light on the oppisite side so as to see through the radiator, got light. I went and flushed it as well with a water hose. I've heard tell about the rock guard, something about a draft or something like that.... elaborate if you will.
Thanks
Harry

Periscope Man · 11-20-2006, 11:49 AM

KOALKAVA, I have an ISL 400 in my coach and I think it runs a little hot (195-197) on flat roads and I have seen it get up to 212 in the small mountains here on the east coast. I questioned the temps right after taking delivery and was told they were that high because of the new low emission engines. My older ISC 330 used to run about 180 on the flat and maybe 195 in the same mountains as above. Could your thermostat be defective?

Periscope Man · 11-20-2006, 11:53 AM

KOALAVA, I see you are from Virginia, the small mountain I was talking about was "AFTON Mt. between Charlottesville and Staunton towing a Honda Odyssey

cmolling · 11-20-2006, 01:04 PM

Koalava:

I had an overheating problem after returning from Alaska several years ago. After the radiator was cleaned out the problem disappeared until recently.

You mentioned that "prior to the trip all fluids were changed and antifreeze was good." That could be the source of your problem. When I complained recently a Cummins mechanic said my radiator was clean. He then proceeded to show me that the radiator cap on the antifreeze reservoir appeared to be tight but actually was about 1/4 turn from being locked. He said that leaving a small leak in what should be a sealed system can result in overheating. I like you had had the antifreeze changed recently and just assumed that everything had been done correctly.

I hope your solution will be as easy (and as cheap).

deandec · 11-21-2006, 07:40 AM

Used to have the same problem on CTA 8.3L 300hp Cummins for about two years.

I needed to keep RPMS over 2000 to defeat the overheating while on an uphill grade. My transmission heat would rise also unless I kept that RPM. ( I go up those 7% grades at 35mph)

Since then I have had the radiator flushed and coolant changed, changed the radiator cap, and changed the coolant filter.

The engine now runs at about 175 degrees on the flat with a rise to 190 degrees on grades. I still run the engine at 2000 to 2100 on steep grades.

Dean
1995 CC Magna