Thermostat thread

[bosssho]

Is there any caveat to running a 170F Thermostat here in MA/NH where temps in the winter get to the negatives? I seem to recall hearing something about that way back when I was looking into on my 87 Mustang GT...

 

[Digger]

After getting tired of my truck running temps of 225+ and 235-240 when pulling my trailer I installed the SPD 170 thermostat today. It was over 90 degrees here today and I never saw the temp higher than 190 at any point today. It was running 178-188 the whole day and I was hard on it trying to get it hot.

 

[TXRaptor]

After getting tired of my truck running temps of 225+ and 235-240 when pulling my trailer I installed the SPD 170 thermostat today. It was over 90 degrees here today and I never saw the temp higher than 190 at any point today. It was running 178-188 the whole day and I was hard on it trying to get it hot.

That sounds like a good change for those of us living in the south. I live in Texas and we have *many* days over 100 degrees in the summer.

 

[DrumReaper]

That has convonced me to change out my thermostat.

I’ll do that with an inter cooler change, tuner and exhaust.

Question... Not to take away from the OP’s post but I was gonna change to a diff CAI, but if I use an Airaid reusable dry filter would that be good enough alone?

 

[Digger]

Pulled my 24 trailer to the races yesterday and the highest temp I saw was 207 and it just briefly and then it quickly dropped back to 198-199 for the whole drive to the track. I was very happy not to see the 235-240 degree temps that I was seeing while pulling my trailer.

 

[nikhsub1]

After getting tired of my truck running temps of 225+ and 235-240 when pulling my trailer I installed the SPD 170 thermostat today. It was over 90 degrees here today and I never saw the temp higher than 190 at any point today. It was running 178-188 the whole day and I was hard on it trying to get it hot.

How much water did you lose when swapping it out?

 

[Digger]

How much water did you lose when swapping it out?

Probably 1/2 gal.

 

[Guy]

My fear is January when it’s 8 degrees and you drive for 45 minutes before the truck is properly warm.

Give and take with everything.

Pulled my 24 trailer to the races yesterday and the highest temp I saw was 207 and it just briefly and then it quickly dropped back to 198-199 for the whole drive to the track. I was very happy not to see the 235-240 degree temps that I was seeing while pulling my trailer.

 

[FORZDA 1]

My fear is January when it’s 8 degrees and you drive for 45 minutes before the truck is properly warm.

Give and take with everything.

Yeah, I would never go lower than 180 on a street vehicle. I've seen 216-217 on my 2018 with relatively heavy load, but drops right back to 205-208 most of the time. The thermostat shouldn't be causing the max temps to go higher than 225 though. Especially if a different thermostat allows lower max temps. The crack and max open temps are set by the thermostat, but the max temp seen should not be a thermostat problem, but rather a pure cooling/coolant problem. I'm wondering if the OEM thermostat may have some inherent flow or temp sensing (design) problem. The newer thermostat designs are all fail-open rather than the older fail-closed versions...

 

[nikhsub1]

My fear is January when it’s 8 degrees and you drive for 45 minutes before the truck is properly warm.

Give and take with everything.

It doesn't work that way. IIRC the OEM thermostat is 195 - so 25 degrees hotter than the 170. In really cold weather, the truck's water should remain around 170ish, just as the 195 should remain around 195ish in that weather. Oil temps will still get to operating temps etc. All thermostats stay closed until the set temp is reached, then they open and stay open unless the coolant gets below the temp and the thermostat should close again. Anyway, if you live in super hot areas or are routinely towing it can't hurt I guess.