How Can I Stop The Diesel Engine On My RV From Overheating?

by Phil
(Washington )

My Allegro Bus has 1a at 300 engine. I have great difficulty keeping it from overheating; gauge into the red most of the time; even in cool weather; despite shifting down (Allison 6) and keeping revs up. Would synthetic oil help?

ANSWER: Greetings Phil thanks for submitting your question on our Ask An RV Question Page.

Let me start by saying that changing the oil you are running in your Diesel engine to synthetic oil will not solve the problem you are experiencing with your engine. Yes, it is a fact that oil in diesel engines plays a bigger role in keeping the engine running cooler than it does in gasoline powered engines. The fact still remains that the change of oil will not fix the underlying overheating problem.

Your diesel engine should not be overheating whether you are using regular oil or synthetic. You have to determine what is causing the engine to overheat. I cannot diagnose your engine problem over the internet, but I can give you some ideas on what the problem could be. Below I have listed some common problems that could cause your Diesel Engine to overheat.

1. Low water level in the cooling system.
2. Leaking or collapsed radiator hoses.
3. Bad thermostat.
4. Blockages in the radiator.
5. Bad Water Pump.
6. Loose fan belt.

The problems I listed above are the more common causes of engine overheating. There could be other problems that are causing your engine to overheat.

The bottom line is that you should not be driving your motorhome with an overheating engine. It concerns me when you say that the temp gauge is in the red most of the time. Each time you drive your motorhome while it is hot you have the potential of seriously damaging the engine. You need to have the motorhome looked at and repaired immediately.

If you continue driving it in its present condition you are setting yourself up for some very expensive engine repairs above and beyond what it would cost to repair the overheating problem.

I hope that this information has been helpful to you.

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Happy RVing

RVing Al