Engine temps lower than usual

[Schwind]

I need ya’lls opinions on this problem.

I unhooked my trailer from my truck yesterday and went on a 200 mile trip. My truck operating temperature mostly pulling a trailer is between 180 and 210. On the run without the trailer it was at or around 180 on the way down. This is using the factory temp gauge so I am going by the lines between the numbers. Normally the needle stays at the third mark between the 160 and 210 numbers. On the way back the needle was staying on the first line after the 160 mark. I know that lower engine temps are unusual and probably shouldn’t complain about it, but I don’t want to run into a situation were the temp sensor has gone bad and will not register properly. I am thinking it is just the thermostat. The money for them is not to expensive. It’s the 45 miles each way to get the parts that I dread.

What I would like to know is if anyone else has had this happen. How I might check the temp sensor or what is the first thing to look at.

The ambient temp yesterday was around 76 degrees.

This truck very seldom sees the road without the trailer anymore. I almost forgot how well it runs without it.

 

[Acesneights1]

94, Single Thermostat IIRC(my 95 is). It MUST be a factory GM for starters. If you can wait a few days Heath sells the Ac/Delco ones Shipping cheaper that 90 miles driving. Take your old one out and heat water on a stovve to 180 and see if it opens then let it cool donw and see where it closes(I always just change it and never bother to do that trick. My opinion always was if you went through the trouble to pull it, change it.) It will be normal to see lower temps not towing but if you have the proper themostat(I think the GM one is 180 ?) then that is pretty much the temp you should see at this time of year.

 

[Schwind]

Thanks Ace. when i pull it I will replace it, no sense in putting the old back in and having to do it again soon.

 

[qwomack]

For what it's worth, Schwind, mine runs at a tick above 160* unloaded and between 3 ticks over and 210* loaded. What I'm saying is what you are describing sounds normal. One thing I have noticed is that the factory gauge is not very accurate. With a scanner plugged in and monitoring the PCM coolant sensor, I have seen differences of about 20* between the 2 sensors.

A new thermostat is not a bad idea however given the fact that these trucks are prone to overheating issues.

 

[Rodd]

The factory guage is not correct. Mine says it is cooler than it actually is too. Normal is about 195-200 range for mine.

 

[Schwind]

Well now I don’t know if it’s the thermostat or the sending unit. After I did the OPS relay today I drove the truck around for awhile and the needle on the temp gauge was sitting in its normal operating range for my truck. I have yet to get either of the items because the stealers (closed on the weekends) are the only place to get the thermostat from here. Any ideas as to which one would be intermitting?