Community Forums

bertb · 07-25-2007, 11:50 AM

Help---my husband and I bought a 1998 Safari 40' diesel pusher-with a Cat --we have had it out about 3 times and it overheats under a load--
he has checked the radiator and that doesn't seem to be the problem--
We have never had a diesel before, so any help would be appreciated

bertb · 07-25-2007, 11:50 AM

Help---my husband and I bought a 1998 Safari 40' diesel pusher-with a Cat --we have had it out about 3 times and it overheats under a load--
he has checked the radiator and that doesn't seem to be the problem--
We have never had a diesel before, so any help would be appreciated

cmolling · 07-25-2007, 01:07 PM

We had a similar overheating problem after traveling to Alaska with all its dust and dirt. A gentle pressure cleaning of the radiator solved the problem.

Several years later it again overheated. A Cummins mechanic checked and told me about a little known problem. The reservoir showed that it had sufficient antifreeze but the cap was not installed tightly. Someone apparently had checked the level of antifreeze and then only partially tightened the cap. For some reason not having a tight seal (vacuum?) caused the sensors to indicate overheating. Just an addition 1/8 turn of the cap and the problem was solved.

Chuck

Route 66 · 07-25-2007, 01:10 PM

Bertb, welcome to iRV2.

Sorry you're having trouble.

The common things are; radiator fins clogged with dirt, or improper coolant mixture.

We should have some CAT owners along soon with some help.

Let us know how you make out.

Ken Roberts · 07-25-2007, 01:47 PM

bertb, dimes to donuts it is the CAC (charge air cooler) which looks like a radiator and is on the front side of the radiator when looking in while standing outside.

There is an easy test, in the dark one person outside shines a flashlight into the fins while another person inside checks from under the bed to see if the light can be readily seen. If it can not you have blockage.

Solution: wet the CAC down and then with a spray bottle apply Simple Green very liberally. Let sit 15-30 mins. rinse with either power washer or heavy hose spray being careful to stay off of the fins where they can be damaged. If you get a lot bof giunk out repeat treatment until all you see is clear water coming out.

Recheck after dark with the flashlight and you should see mega improvement. This maintenance procedure needs to be done twicee a year and maybe more often if you travel extensively in dusty environments, Good luck, Ken, '04 DSDP...

DonavonP · 07-25-2007, 03:12 PM

Here's some additional reading on why the radiator gets so dirty and how to correct it.

Welcome to the forum.

Pusherman · 07-25-2007, 04:30 PM

There is a lot of info in this forum relative to how rear radiator diesels get gunked up and need to be cleaned regularly. One of the causes is the engine crankcase ventilation, also known as a slobber tube, which depending on where it's located, can gunk up a rear radiator coach real quick. Read about them here.

Regular maintenance of rear radiator coaches includes cleaning the radiator 2X/year. Use a solvent such as Simple Green, sprayed into the radiator from the rear to the engine side, and if you can get access to the engine compartment, from the engine side to the rear as well.

Do this on a hot radiator, and let sit for 15+minutes. Then flush with a garden hose from the rear to the engine side. Repeat until you get clear water out. Note: pressure washers can bend the fins on the radiator, and are not recommended for this purpose.

This will solve most of your overheating problems, and save you significant $$ if you do it yourself.

bldrbob · 07-28-2007, 05:04 PM

I had problems with overheating on long pulls.After cleaning the radiator I extended the slobber tube past the radiator.By downshifting to keep the rpm up I didn't have anymore problems.
BOB

Jestme13 · 07-30-2007, 05:29 PM

everytime I come back from a trip and wash the coach I flush the Radiator with a strong flow of fresh water. An ounce of prevention is the way I see it.

Gary RVRoamer · 08-02-2007, 01:00 PM

Another thing that will cause overheating under load is a tiny pressure leak in the radiator - could even be the cap. Won't lose much, if any, water, but it keeps the pressure inside at outside air pressure. Modern radiators are designed to run at higher pressures so the water can exceed the boiling point.