If the stat is stuck closed, the car will overheat

If the stat is stuck open, the car will take longer to warm up, will not cause the car to overheat, engine temp controlled by lo/hi fan operation.

If the car used to run 170 (fans must have been running on hi at all times) maybe the increase in temp is fan, water pump, or air flow related.

You can run WITHOUT a stat and the car will take longer to warm up, will not cause the car to overheat, engine temp controlled by lo/hi fan operation. The only problem is there is no control for the lowest temp which is what the stat controls. The stat operates at the "low" temperature setting. The fans operate to maintain operating temp and to not allow overheating.


Additionally, when NLP did the work and installed the LS6 on my car (98 Camaro Z) for the twins, they put in a 170 or 160 stat and cranked the fans lower. I have the SLP fan switch on the Z and it has 2 lights. The lights tell me when the fans are running lo or hi. With the setting NLP used. my fans were running when I was driving down the highway at 70 and that is wrong. My fans NEVER turned off. I pulled the lo temp stat and put the stock one back in and I raised the fans to stock temps. Now the car cruises at highway speeds and the fans are off while the air flow from driving keeps the car cool EVEN HERE in Florida. Is it wrong to use a lo temp stat and lower fan settings? No, what do you want from the car. Constant 1/4 mile performance preparedness? Then use lo stat & lo fan settings. Drive the car in city and highway traffic and use the fans when needed? stock stat and fan settings. Ok, so I might lose a tenth in the 1/4 mile but it is NOT worth the hassle to me to have the fans on at all times for NOTHING.

My $.02


Elmer

 

I'm wondering if the fans are running at highway speeds which would actually reduce air flow thru the radiator I think. I think the speed would push more air thru than the fans would so the fans may be blocking some air from flowing thru the raidiator.

 

Not really. The air flow is usually more than enough to cool the engine. The fans don't run at highway speed and probably free wheel (I've never had the hood up and my head in there at 70 MPH to check). Any low flow of air is a restriction (trash bag eg.) by a foreign object.

My example of the NLP settings had the fans running and they were not affecting the cooling at highway speeds one way or the other.

 

The stock fan settings on the Vette do not even trigger til they hit 199 degrees (on an LS3 anyway). They can't even be forced to trigger until 192 so they are not really doing anything at highway speeds.
Resetting the fans to ramp up earlier from 192 to 199 will keep the temps nice and stable at around 200 degrees at idle in traffic with a 160 stat.

Here are the stock fan settings. If they are not adjusted, temps will generallly run 15 degrees higher at idle with either stat.

 

I understand and agree with you. My example was on my Camaro with the LS6 engine and the fans could be set much lower and RUN at most any speed. The Vette is different and has a higher fan range.

I am still trying to figure out how he was running at 170. Since you can't slap the fans until 192, how was it running at 170? That would be setting it to 90 on ALL the fan options.

 

Bad thermostat. Zpirate got 2 in a row. The car would run at 160 or lower! A temp test in hot water with a thermometer showed his (supposedly) 160 stat was opening at 140 degrees. This has been reported here on several occasions.

 

OK, bad t-stat.

Bad as in..

Open all the time: temp will come up slow and be controlled by fans after 192+

Opens late: temp will come up normally and be controlled by fans after 192+

 

It's been demonstrated here on several occasions, that the cooling system has enough capacity on the highway, even on a hot day, to cool the car to 160 or lower given a bad, stuck open, or No stat.

 

So the stat is not opening up as designed and that would be why he's running warmer. Ok, that makes sense but this condition is only when running on the highway. In city, he'll not see 170 except when the gauge is passing by the number.

 

Are you sure it isnt just the fact that it's summer now?

 

one correction. If the Tstat sticks open the car will run Hotter beacause the coolant gets heat soaked from not being able to stay in the radiator long enough to cool. This is why track cars that run no tstat overheat, like when they run in true street compatition which requires a 15mi out and back cruise before drags start.

 

With the stock stat it would stay around 203 running down the interstate even in mid summer heat. Right now with the 160 I'm running anywhere from 199 to 207. Typically if you watch your heat gauge you can tell when your stat opens. Temp steadily climbs until the stat opens, at which time you will see temps stop rising or even cool down a bit. If you are moving down the road the temps will generally stay a little above what the stat is rated for (maybe 10-15 degrees). At least that is my experience from the old days. Now maybe with electric fans in the mix instead of engine driven fans this may be somewhat different now? I had the stat put in around the first of May so outside temps were cooler for sure but when I leave for work in the mornings now when it's 60 degrees out I don't expect to see 207 cruising down the interstate with a stat that is 30 degrees cooler than stock. Thanks for all the input so far. My main concern is that Chuck "requires" a 160 stat with his tunes so if my car is running teh same or higher temps than the stock stat ran, it concerns me. I talked to him last night and he wants me to pull the stat and make sure it's lined up correctly and the pinto valve can move freely. I guess that's my next step. I even took the vararam off and hooked up a vortex rammer just to see if the vararam was blocking enough air flow to make a difference. Made no difference except it didn't pull as hard.