Engine Temp running cool

wotexva99 · May 9, 2014

I have a 01 1500 HD (154,xxx miles) and as long as I can remember my engine ran at about 210 (right below it). However this week I noticed it was running at at about 180-185f (. It would stay at that temp on streets or highway driving. So, yesterday I replaced my thermostat with the 187f therm which is what comes from the factory. However today it got up to 210 then dropped to 185 or so and stayed there.

How come it is running cooler now when it has always ran a hair under 210f? The only thing I could think of is maybe the coolant temp sensor is bad but IDK.

Here is where it runs at now(red line) and where it used to run (stock needle)

00Silverado4x4 · May 9, 2014

I could be wrong, which is always possible, but I thought the stock thermostats for these trucks were 195*? Don't know why that would make such a difference but I think you may have gotten the incorrect temp rated thermostat.

efritz · May 9, 2014

I accidentally bought a lower temp stat and it did that. The only possible negative effect would be very slightly lower mileage as temps would be lower. You really need to get a scantool that can read live data to make sure the gauge isn't inaccurate.

txab · May 9, 2014

I accidentally bought a lower temp stat and it did that. The only possible negative effect would be very slightly lower mileage as temps would be lower. You really need to get a scantool that can read live data to make sure the gauge isn't inaccurate.

+1

Gurrzt · May 9, 2014

I accidentally bought a lower temp stat and it did that. The only possible negative effect would be very slightly lower mileage as temps would be lower. You really need to get a scantool that can read live data to make sure the gauge isn't inaccurate.

+1

Unless you adjust your "on/off" temperature of your fans (ECM adjust) it does not matter what temperature the thermostat is, the water will heat up to the prescribed temperature the fan is programed to.

wotexva99 · May 9, 2014

The therm I pulled out said 86c which converts 187f

Why did it run at a lower temp with old therm(for a week or so) and new therm?

00Silverado4x4 · May 9, 2014

Unless you adjust your "on/off" temperature of your fans (ECM adjust) it does not matter what temperature the thermostat is, the water will heat up to the prescribed temperature the fan is programed to.

This is true, but since he only replaced the thermostat, why is it now running cooler with the same program but new thermostat? That's what's got me curious.

txab · May 9, 2014

Unless you adjust your "on/off" temperature of your fans (ECM adjust) it does not matter what temperature the thermostat is, the water will heat up to the prescribed temperature the fan is programed to.

Except for the fact 2001 models do not have e-fans..........

Chris · May 9, 2014

187 is the correct therm. 195 is the operating temp. 187 is just the temp where the thermostat opens to let coolant circulate

wotexva99 · May 9, 2014

This is true, but since he only replaced the thermostat, why is it now running cooler with the same program but new thermostat? That's what's got me curious.

187 is the correct therm. 195 is the operating temp. 187 is just the temp where the thermostat opens to let coolant circulate

Why did it always run hotter til now with new therm???

Chris · May 9, 2014

That one I cant answer. When searching for new thermostats the factory replacement I find is 187.

wotexva99 · May 9, 2014

The only thing I could think of is maybe the coolant temp sensor is bad but IDK. I am little concearned only because I am heading up the Cajon pass to Barsrtow towing about 1500-3000lb in my utility trailer on Memorial Day weekend

Gurrzt · May 9, 2014

Except for the fact 2001 models do not have e-fans..........

The only vehicle I can reference is "Sara" (2001 Camaro Z28) and she DOES have "e fans". I to installed a 185F thermostat in her, and when I had a dyno tune (for other matters), I had the tuner set the fan on/off speed to correspond with the lower thermostat.

Chris · May 9, 2014

The only thing I could think of is maybe the coolant temp sensor is bad but IDK. I am little concearned only because I am heading up the Cajon pass to Barsrtow towing about 1500-3000lb in my utility trailer on Memorial Day weekend

Running slightly cool is fine. That pass isnt that bad for your truck and only towing up to 3000 pounds. There is a lot worse in the area thst I can think of.

wotexva99 · May 9, 2014

Thanks for the input Chris. Btw, I'm heading to Barstow(Slash x area) to go riding in a few weeks and just want to make sure my truck is running up to par

Edited May 9, 2014 by 1500HD Todd