Coolant temperature question
Thread Starter
Pro
Joined: May 2008
Posts: 661
Likes: 2
From: New England
Coolant temperature question
My 2004 has had a 160 degree thermostat and reprogrammed fans for about 5 years. Today the outside temp was only about 84. Wondering how/why the coolant temp could get up to 220 even with a 160 thermostat?
I'm NOT worried about that temp in general. Just curious what might have changed. Normally it wouldn't go over 190.
I don't want to make this a debate about 160/180 thermostats. Thanks
I'm NOT worried about that temp in general. Just curious what might have changed. Normally it wouldn't go over 190.
I don't want to make this a debate about 160/180 thermostats. Thanks
Burning Brakes
Joined: May 2013
Posts: 1,249
Likes: 142
From: Lynn MA
I don't have an answer for you but a possible solution. I swear by water wetter by Redline. I was having issues in warm to hot weather with higher than normal temps. Did some research and found it to be a good option. Well bought a 12 oz bottle and added it and it knocked the temp down about 20 degrees. Worked so well I put a bottle in my 2005 supercharged GTO and got the same results. It's something you can try and it won't hurt anything and it's just $10.00
Burning Brakes
Joined: May 2005
Posts: 837
Likes: 98
From: Philo IL
A thermostat that is stuck closed will also cause temps to go up. Can't cool water that doesn't circulate. Also, check to be sure that the fans are operating. Could be possible that one of the motors pooped, wiring has been damaged somehow, or maybe even a bad fuse or relay could keep them from turning on. Just some ideas on things to check.
Last edited by oneandgone; Jul 1, 2017 at 06:55 PM.
CF Community Team
Joined: Oct 2004
Posts: 19,339
Likes: 5,232
From: Cape Cod, Mass.
2025 C6 of the Year Finalist - Unmodified
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
2021 C8 of the Year Finalist Unmodified
2020 Corvette of the Year Finalist (performance mods)
2019 C1 of Year Winner (performance mods)
2017 Corvette of the Year Finalist
2016 C2 of Year
2015 C3 of Year Finalist
The 160 thermostat is just the opening temp to provide water circulation and it DOES NOT guarantee that the coolant temp will stay below a set value. That job is left to the correct operation of the cooling system including getting adequate air flow through the radiator fins.
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
you are right on the money 
The thermostat only dictates the temp at which it opens. After that it's up to the quality and condition of your entire system to keep it cool.
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,271
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
if it has been running 190 consistently for the past 5 years and now suddenly went up to 220 I agree with starting at the radiator fins and making sure they are clean... also check the coolant level and check for any small leaks if the coolant level is low and might as well make sure both fans are operating... I had a similar issue a couple of years ago where one of my fans quit working and caused my temps to go up to around 230 and usually it sits in the high 190's to 200
Administrator
Joined: Mar 2001
Posts: 367,271
Likes: 24,567
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
The 160 thermostat is just the opening temp to provide water circulation and it DOES NOT guarantee that the coolant temp will stay below a set value. That job is left to the correct operation of the cooling system including getting adequate air flow through the radiator fins.
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 326
From: CA.
St. Jude Donor '13-'14-'15
If with the 160 thermo it ran cool then now it begins to run like 190 with normal temps can point to a few things
1 your thermo is NOT working properly anymore either stuck open or slightly closed
2 your fans are NOT coming on
3 your radiator fins are clogged with debris
4 Your coolant is OLD
5 If your car s an automatic you have to remember that the trans fluid is cooled by your radiator-----IF your trans is running HOT it will in turn make your coolant temps HOT as well---Try changing your trans fluid old fluid will run hotter--- inspect the trans filter--
1 your thermo is NOT working properly anymore either stuck open or slightly closed
2 your fans are NOT coming on
3 your radiator fins are clogged with debris
4 Your coolant is OLD
5 If your car s an automatic you have to remember that the trans fluid is cooled by your radiator-----IF your trans is running HOT it will in turn make your coolant temps HOT as well---Try changing your trans fluid old fluid will run hotter--- inspect the trans filter--
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,439
Likes: 2,183
From: Buffalo Texas
The 160 thermostat is just the opening temp to provide water circulation and it DOES NOT guarantee that the coolant temp will stay below a set value. That job is left to the correct operation of the cooling system including getting adequate air flow through the radiator fins.
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
I would start by getting the car up in the air and insuring that the cooling fins are clear of debris so that air can flow in order to be able to cool the water in the radiator. Bet there is plenty of junk against the fins preventing air flow. Perhaps even a plastic bag or two that got sucked in as the C5 is a bottom feeder for radiator cooling air........
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Put a jacking puck under and jack up a side (you choose which side) and take a look. I had a T-shirt wrapped around the left fan.....it took out the fan, the fuse and the relay. Do an inspection...it will take five minutes if you put down the beer.
Sorry, to post on yesterdays story, was out of the country for the past two weeks. JFK on the 4th of July was something else.
Sorry, to post on yesterdays story, was out of the country for the past two weeks. JFK on the 4th of July was something else.
Last edited by runner140*; Jul 5, 2017 at 06:33 AM. Reason: add
Racer
Joined: May 2010
Posts: 250
Likes: 1
From: MA
I changed my coolant last weekend and found my radiator and AC condenser both full of grass and dirt. To clean them you don't actually have to pull the radiator. Pull the air deflector out in front of the condenser and you can lift it off the radiator where it hooks. You'll find you can now fit a garden hose and a sprayer between the condenser and radiator and power wash the crap out. First clean all the grass off with a brush. My car now runs 2-3 degrees cooler and never over 205.
Advanced
Joined: Feb 2017
Posts: 94
Likes: 0
The Pantera must be given it's due respect. When I was 16 I heard an amazingly loud yet nicely cammed motor coming up the street I looked out to see one of the most radical looking and sounding cars. I asked my brother what it was an he said," Dude that's a Pantera!". Since that day I have always loved the Pantera. Oh throw a Cobra in there too for radical car tip of the hat.
But all that being said neither of those cars platforms flourished throughout time like the Corvette. They only became antiquated. But still bad ***!
But all that being said neither of those cars platforms flourished throughout time like the Corvette. They only became antiquated. But still bad ***!
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,439
Likes: 2,183
From: Buffalo Texas
The Pantera must be given it's due respect. When I was 16 I heard an amazingly loud yet nicely cammed motor coming up the street I looked out to see one of the most radical looking and sounding cars. I asked my brother what it was an he said," Dude that's a Pantera!". Since that day I have always loved the Pantera. Oh throw a Cobra in there too for radical car tip of the hat.
But all that being said neither of those cars platforms flourished throughout time like the Corvette. They only became antiquated. But still bad ***!
But all that being said neither of those cars platforms flourished throughout time like the Corvette. They only became antiquated. But still bad ***!
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,439
Likes: 2,183
From: Buffalo Texas
Advanced
Joined: Feb 2017
Posts: 94
Likes: 0
Pantera not related to this topic...I was responding to some how "related thread".
That being said....I was having extraordinary high temp issues as well. Installed new radiator and new 180 stat. Still had intermittent elevated temps while stuck in traffic. Tried the Redline Wetter Water and brought temps to 190/ freeway and stuck in traffic temps down to 215.
That being said....I was having extraordinary high temp issues as well. Installed new radiator and new 180 stat. Still had intermittent elevated temps while stuck in traffic. Tried the Redline Wetter Water and brought temps to 190/ freeway and stuck in traffic temps down to 215.