Erratic coolant temps ?
Thread Starter
Pro
Joined: Sep 1999
Posts: 518
Likes: 0
From: South Florida
Erratic coolant temps ?
I re installed my OEM stat and everything is fine for about a month, now it seems that the coolant temp is at times erratic and does not stay steady at 194 like it used to. For example I see temp going down to 180's on the highway then climb back to 190's (car never went below 192 on the highway). I also got a "check coolant level" message, however the coolant level is fine.
I don't mind the lower temps but something doesn't seem right, could the oem stat be the problem, no other mods have been done to the car, this is driving me
any ideas?
I don't mind the lower temps but something doesn't seem right, could the oem stat be the problem, no other mods have been done to the car, this is driving me
any ideas?
Drifting
Joined: Jun 2005
Posts: 1,837
Likes: 4
Definitely a problem; possibly some air in there. Should stay right on "normal" (195 or so) when driving down the highway. Of course its possible that the thermostat is bad or was damaged, but that doesn't seem very likely when the description includes "erratic".
It is possible to get false low temperature readings due to air in the system; this is caused by the temperature probe being in the bubble, which isn't a very good conductor of heat.
I believe that the coolant level isn't measured, but is calculated based on uneven temperatures - which is consistant with what you're seeing, and with an air problem.
Did this problem perhaps show up soon after the first time the heater was used after the thermostat was swapped? Could be some air in the heater system got in when the valve opened up.
So I'd look into "burping" the system.
It is possible to get false low temperature readings due to air in the system; this is caused by the temperature probe being in the bubble, which isn't a very good conductor of heat.
I believe that the coolant level isn't measured, but is calculated based on uneven temperatures - which is consistant with what you're seeing, and with an air problem.
Did this problem perhaps show up soon after the first time the heater was used after the thermostat was swapped? Could be some air in the heater system got in when the valve opened up.
So I'd look into "burping" the system.
Safety Car
Joined: Jun 2004
Posts: 3,563
Likes: 2
From: Dallas Tx
to see if any air is in the system. Start it cold with the pressure cap off the surge tank. Idle for 4 minutes. Then run it 2000 rpm for 2 minutes. Then idle it for 2 minutes. If the coolant level went down, there was air in it.
Safety Car
Joined: Apr 2006
Posts: 4,254
Likes: 5
From: Anaheim Hills, Ca
Air is my bet. The air bubble will show a lower temp when it hits the sending unit and since you drained fluid when changing the stat back to the stock one, you got air in the system. It shouldn't ever go below 192 although it will fluctuate higher in stop and go or slow speeds.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Pro
Joined: Sep 1999
Posts: 518
Likes: 0
From: South Florida
Definitely a problem; possibly some air in there. Should stay right on "normal" (195 or so) when driving down the highway. Of course its possible that the thermostat is bad or was damaged, but that doesn't seem very likely when the description includes "erratic".
It is possible to get false low temperature readings due to air in the system; this is caused by the temperature probe being in the bubble, which isn't a very good conductor of heat.
I believe that the coolant level isn't measured, but is calculated based on uneven temperatures - which is consistant with what you're seeing, and with an air problem.
Did this problem perhaps show up soon after the first time the heater was used after the thermostat was swapped? Could be some air in the heater system got in when the valve opened up.
So I'd look into "burping" the system.
It is possible to get false low temperature readings due to air in the system; this is caused by the temperature probe being in the bubble, which isn't a very good conductor of heat.
I believe that the coolant level isn't measured, but is calculated based on uneven temperatures - which is consistant with what you're seeing, and with an air problem.
Did this problem perhaps show up soon after the first time the heater was used after the thermostat was swapped? Could be some air in the heater system got in when the valve opened up.
So I'd look into "burping" the system.
this method worked for me, thanks for all the help
