160 deg Tstat
Thread Starter
Instructor
Joined: Apr 2022
Posts: 181
Likes: 118
From: Oregon
160 deg Tstat
I took my new to me '85 for a longer drive today (had to run it through the smog station). I noticed on the drive that it ran about 157 degrees on the highway in 45 degree temps. When I was parked with it running at the smog station, it climbed to 210 deg.
Does this sound like the PO installed a 160 degree thermostat? I would have thought that it would run at 160 all the time, or around 200 all the time if it was stock.
Does this sound like the PO installed a 160 degree thermostat? I would have thought that it would run at 160 all the time, or around 200 all the time if it was stock.
Team Owner
Joined: Sep 2001
Posts: 62,142
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Given the outside temps and you cruising on the highway, yes its quite likely that theres a lowered stat in the car. Only times I ever saw my 86 with a 160 run that cool and stay there is on winter mornings or evenings in the 30s.
A stock stat might not have stayed open very long in 45F cruising but would have run warmer than 157.
A stock stat might not have stayed open very long in 45F cruising but would have run warmer than 157.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Vader is right. You have a 160 stat.
Even though it shouldn't start opening until 160, it's quite possible to "drive the temps down", below the rating. How? All that cold air and you have a COLD slug of water in the radiator, Stat opens and that comes into the block, up through the heads before hitting the stat and closing it again. Meanwhile, Coolant temp sensors sees water under 160 for a brief period.
Even though it shouldn't start opening until 160, it's quite possible to "drive the temps down", below the rating. How? All that cold air and you have a COLD slug of water in the radiator, Stat opens and that comes into the block, up through the heads before hitting the stat and closing it again. Meanwhile, Coolant temp sensors sees water under 160 for a brief period.
Racer
Joined: Mar 2020
Posts: 387
Likes: 148
From: Langton, Ontario, Canada
2025 C4 of the Year Finalist - Unmodified
I use a 160 degree thermostat in the 350 engine in my boat. It runs for hours at a time at about 3400 RPM, making power all the time. It needs to be cool when it's working like that. Corvette engines need to be hotter than that, as they aren't always working hard like that. Engine oil will sludge up if the engine is run too cool. Get a 180 or 190 degree stat and make sure your fans run properly.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Same engine. Oil will not "sludge up" from a 160 stat. Nope, nope, nope. The "Corvette" engine is absolutely fine, running at most any temp the OP chooses to run it at...that you can buy a stat for.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
While I agree with Tom that low operating temps won't cause "sludge", I feel that low temps can contribute to condensation build-up, and milk-shakey oil on the heads. The 327 in my 18' Jet Boat is cooled with bleed-water off of the jet drive. Because there is no recirculating water pump, there can be no thermostat. I have a gate-valve to adjust the water flow and the operating temp. I have to open the valve far enough to keep the exposed exhaust manifolds (water cooled) cool enough at idle to not burn occupants that may contact them. But at speed, with the increased water flow off the jet drive, the engine runs about 150F. If the valve covers are off the first couple of days of a trip, there is condensation on the underside of the aluminum valve covers, and sometimes puddling of liquid water in the low spots in the heads. At the end of a 8-9 day trip, the moisture is gone, and so are any signs of milki-shakey oil.
IME, If you're getting condensation in your oil, (in a car, using a thermostat...any thermostat), that is your driving cycle and that is called "Severe conditions" in your owner's manual. Oil changes should be done accordingly, in that case.
The boat sounds cool, BTW...I totally dig old skool, hot boats. Wish there were more around here to stare at.
Instructor
Joined: Oct 2018
Posts: 225
Likes: 81
From: Vancouver, WA
I took my new to me '85 for a longer drive today (had to run it through the smog station). I noticed on the drive that it ran about 157 degrees on the highway in 45 degree temps. When I was parked with it running at the smog station, it climbed to 210 deg.
Does this sound like the PO installed a 160 degree thermostat? I would have thought that it would run at 160 all the time, or around 200 all the time if it was stock.
Does this sound like the PO installed a 160 degree thermostat? I would have thought that it would run at 160 all the time, or around 200 all the time if it was stock.
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Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
Fact check
The engineers had to meet criteria that we don't have to and we don't care about. Making that case would apply to any/all mods to the car. I.e. you could never change anything on the car b/c "the engineers did if for a reason". But...we (nearly) all change things because we have different goals and criteria than the engineers did.
"People" don't just claim....it's actually been proven. Take some time to read THIS THREAD....then NOTE that in all of the tests referenced in that thread, none of them exploited the biggest power advantage to lower operating temps -the potential to run more timing w/o detonation. They simply gained hp with cooler temps, no other changes.
The ECM doesn't control the temp. The fans don't control the temp (other then when stopped or otherwise "no" air flow). The thermostat controls the lower operating temp range. Cooling system capacity, ambient temps and air flow control the upper end of the range. An engine w/a 160 stat will run a minimum of 160 -even in the coldest temps, and it will warm up to 160 just as fast as the same engine with a 195 stat.
Neither choice is "wrong"....it all depends on the goals. Many 'Vette owners like "more power", so....that's a common goal/criteria.
.
The engineers had to meet criteria that we don't have to and we don't care about. Making that case would apply to any/all mods to the car. I.e. you could never change anything on the car b/c "the engineers did if for a reason". But...we (nearly) all change things because we have different goals and criteria than the engineers did.
Neither choice is "wrong"....it all depends on the goals. Many 'Vette owners like "more power", so....that's a common goal/criteria.
.
Last edited by Tom400CFI; Apr 23, 2022 at 11:15 AM.
Thread Starter
Instructor
Joined: Apr 2022
Posts: 181
Likes: 118
From: Oregon
I drove the car to work a couple of times this week. It runs at 157 going down the highway, but as soon as I stop, the temp starts to climb. Sitting in a drive through it goes up to about 228. This is all in ambient temps in the 40’s and low 50’s. I am doing a full tuneup and fluid changes on the car this weekend. Part of the service will be installing a factory thermosat.
Team Owner
Joined: Sep 2001
Posts: 62,142
Likes: 1,729
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
I drove the car to work a couple of times this week. It runs at 157 going down the highway, but as soon as I stop, the temp starts to climb. Sitting in a drive through it goes up to about 228. This is all in ambient temps in the 40’s and low 50’s. I am doing a full tuneup and fluid changes on the car this weekend. Part of the service will be installing a factory thermosat.
Wouldn't be a bad idea to flush your coolant system and replace all the coolant, along with the radiator cap, if you're changing the stat out.
Instructor
Joined: Oct 2018
Posts: 225
Likes: 81
From: Vancouver, WA
I drove the car to work a couple of times this week. It runs at 157 going down the highway, but as soon as I stop, the temp starts to climb. Sitting in a drive through it goes up to about 228. This is all in ambient temps in the 40’s and low 50’s. I am doing a full tuneup and fluid changes on the car this weekend. Part of the service will be installing a factory thermosat.
