95 Dodge with a one day old radiator...replaced that because the temp gauge is working overtime... The truck has an 11 year old themostat (could that be the problem??)... I read some forums and it just seems like there is so much more that it could be... I am 6k into this truck this year and it's only July.... does anyone have a similar problem... the fan doesn't seem to change speeds at all when the truck reaches 190 idling.... Thanks...

 

Is the gauge just moving around or is the truck actually overheating? These trucks have large cooling systems and they tend to swing the gauge a lot. A new Cummins thermostat might settle the gauge down a little, but don't expect it to be rock steady.

 

Agree with earlier post. I think there was a TSB and updated thermostat. The updated thermostat still had a temp swing. Looked like truck was prepared to overheat then thermostat needle on dash would drop out. If this isn't the problem you have an air embolism. Air pockets in the cooling system don't work well. Especially if radiator is one day old. Not sure what the easiest way to remove the air. I think professional mechanics have a machine to assist. I usually pump the upper radiator hose with the radiator cap off.

Could redrain system. Replace thermostat. Remove upper radiator hose. Fill system to the level of the upper hose then reinstall. The 12V has a small thermostat bypass hose that should help drain any residual air at this point. Try search for other ideas.

 

Normally, the removal of air process if to run the truck with th eoverflow tank filled properly. The air will be expelled into the overflow tank and when the engine cools it will suck fluid from the overflow tank back in, reducing or eliminating the air in the cooling system.
When filling, you can get most of the air out by heating the engine until the thermostat opens, and filling the radiator up at that time. I normally don't do this. I just fill it up cold and let the overflow tank do it's thing.

I second the temp gauge thing. Even on a hot day, my 96 swings WIDE on the gauge. This is just a tendency of the 12v engines, although I have heard of some that don't do this. I wish I knew what thermostat was in those trucks.

Chris

 

I have the same issues with my 95 the gauge seems to be moving all the time,but I have not had any overheating problems and I am over the road every day.Does anyone know what the rating on that new stat is??

 

I had the newer stat in my 96'. The swing on the needle wasn't as pronounced but still existed.

 

So what was the temp before and after... right now it opens a lot... I want to say at least once a mile from 150-190 degrees... 210 on uphills... that seems too much.. does it still seem to work as much... this truck has had too much work and $$$$ for the past two years