Community Forums

411jeff · 08-15-2015, 01:18 PM

I have a Cummins diesel engine (Mechanical 300 - Turbo - 6C8.3) in my '98 Monaco Dynasty. It has been running hot, but not in the red. Just under 220 degrees according to my gauge. This doesn't happen all the time. It can happen during the day or night. It can be running fine for 4 hours then I stop to get fuel and it starts running hot. The fluid level is fine.

Has this happened to others?

Thanks for your help.

jacwjames · 08-15-2015, 03:55 PM

You cooling fan may not be working properly. When it is running hot can you notice if the fan is running. My 350 HP ISC will run 180 up to ~190. The fan should be running if it is that hot.

If the fan is running it may be a thermostat that is hanging.

Lastly, have you checked your radiator, when was the last time you cleaned it. Since your heating problem is sporadic I doubt it's the radiator but you could check.

stich · 08-15-2015, 04:26 PM

My 98 Executive did the exact same thing. Went on vacation for two weeks and half way through, it started running about like yours, 220 or a little less. After we got home I made appointment for the mechanic to check it out and of course, it wouldn't repeat the problem. No matter what I did I couldn't get it to go above 185. His thoughts as were mine was that the high speed fan wasn't coming on but now it is. I'll be leaving in a few weeks for another vacation so we'll see if it does it again. This time I will go around to the side of the coach and listen for the fan as when it is on high you can definitely hear the difference.

411jeff · 08-15-2015, 05:06 PM

Thanks for responding. Let me know what happens after your trip.

411jeff · 08-15-2015, 06:38 PM

Quote:

Originally Posted by jacwjames

You cooling fan may not be working properly. When it is running hot can you notice if the fan is running. My 350 HP ISC will run 180 up to ~190. The fan should be running if it is that hot.

If the fan is running it may be a thermostat that is hanging.

Lastly, have you checked your radiator, when was the last time you cleaned it. Since your heating problem is sporadic I doubt it's the radiator but you could check.

I'll look into the fan.
Thanks for the advice.

Jeff

donnyman · 08-16-2015, 08:46 AM

Hello!
The cost of a thermostat replacement is cheap enough to have done. I would not hesitate to have it done. (i did my own) if for no other reason you will have a new thermostat and you know what it isn't if the problem continues. if it does continue you have a much more expensive situation.