What do you think about this issue

[Chevy Fleetside]

I drove my truck down to San Jose to pick up a piece of funiture. I have been having trouble with it getting hot on the freeway so I thought I would change the thermostat. The one that was in there was sticky so I replaced it with a 160º thermostat and I have a feeling that is just to cold and won't close when the water is hot so the radiator can cool it down. The first picture shows what the temp is like when it is hot outside and the other is when I came back into cooler weather. The truck cools down alot. It was probably 80º in San Jose and about 60º in SF.
I have changed the radiator. I think the next thing I am gong to do is to swap out the thermostat for a 180º.

[GVDobler]

Sounds backwards. I thought it stayed closed until it reaches the temp of the stat so the engine could warm up.

What RPM are you running at that speed? That might be why it runs hot.

[71swb4x4]

A couple things:
1) What's the problem? So it's a little warmer out and the truck runs a little warmer, but still well within the normal range.
2) The thermostat is there to let the engine warm up faster. Once you are at operating temperature the thermostat is not going to close very often, if at all. When you first start your truck the thermostat is closed, once the engine warms up it opens and lets the coolant circulate.
3) If you are concerned buy an aftermarket temperature gauge so you know what temp the truck is running at. Then you will know whether or not you have a problem to fix.

[short&wide65]

Originally Posted by 71swb4x4

1) What's the problem? So it's a little warmer out and the truck runs a little warmer, but still well within the normal range.

I agree. Is the truck actually overheating or is the factory gauge just moving within the specified range?

This is the reason why temperature gauges in new vehicles don't actually work. People don't like it when they fluctuate with temperature and call the dealer thinking there is a problem.

[Chevy Fleetside]

it seems to be ok. When the temp is up like that it is harder to start. It could be reading wrong and it could also have some plugged ports. This truck has about 160,000 miles on it and is pretty much a survivor. The water pump could be rusted out also. I think the reasons could be endless. I will just try one at a time. I do plan on takeing the engine out and resealing it as it leaks all over. When I do that I will have to look at the water ports. There dosn't see to be alot of rust in the cooling system though.
I just posted to get some idea's and some opinons..

[PGSigns]

Buy a real gauge and put it on the truck. That is the only way you will know what it is doing. A thermostat that is a 160 will open sooner and let the engine run a little cooler it will stay open fully and never close down when the engine gets up to temp and under load. A 180 will open later and may close down some to keep it at 180 if the temps out side are a little cooler and may run 190 under load. In the winter when the air is cold and there is no problem getting rid of the heat they may run closer to the number on the thermostat. A 180 will keep the water in the engine longer and keep your toes warmer. My truck has a 180 in it and on a hot humid day runs as much as 195 in traffic. Hard to get rid of the heat. I the winter runs about 185 and that is about all you could hope for. You pics are right about what I would expect.
Jimmy