Correct Thermostate
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
180 'stat will be the right one. A temp of 225 is a bit warm but have you checked for dirt and debris at the front of the A/C condenser and the front of the radiator. That's a common issue with C4's. If everything is dry, you can use a shop vacuum to remove a lot of that junk or use a garden hose from the engine side of the radiator to push everything out.
Also make sure the lower air dam pieces are in place and are not torn up or bent backwards. How old are the hoses? You may have a lower hose that is collapsing and cutting the coolant flow down.
You can also check the cooling fan operation by starting the engine and then turn the A/C on. That will force the fans to start.
Also make sure the lower air dam pieces are in place and are not torn up or bent backwards. How old are the hoses? You may have a lower hose that is collapsing and cutting the coolant flow down.
You can also check the cooling fan operation by starting the engine and then turn the A/C on. That will force the fans to start.
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
If it is really 220 per the ECM, start with the basics. Is the radiator good? Hit it in several spots with an infrared thermometer and see if that is having cold spots. If not, check for air obstruction since the C4 picks up all kinds of crap from the ground.
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
Lets start with "How did you determine that?". I don't know about 95 but on my 91, the most accurate is to see what the ECM sees and not what the gauge sees.
If it is really 220 per the ECM, start with the basics. Is the radiator good? Hit it in several spots with an infrared thermometer and see if that is having cold spots. If not, check for air obstruction since the C4 picks up all kinds of crap from the ground.
If it is really 220 per the ECM, start with the basics. Is the radiator good? Hit it in several spots with an infrared thermometer and see if that is having cold spots. If not, check for air obstruction since the C4 picks up all kinds of crap from the ground.
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
180 'stat will be the right one. A temp of 225 is a bit warm but have you checked for dirt and debris at the front of the A/C condenser and the front of the radiator. That's a common issue with C4's. If everything is dry, you can use a shop vacuum to remove a lot of that junk or use a garden hose from the engine side of the radiator to push everything out.
Also make sure the lower air dam pieces are in place and are not torn up or bent backwards. How old are the hoses? You may have a lower hose that is collapsing and cutting the coolant flow down.
You can also check the cooling fan operation by starting the engine and then turn the A/C on. That will force the fans to start.
Also make sure the lower air dam pieces are in place and are not torn up or bent backwards. How old are the hoses? You may have a lower hose that is collapsing and cutting the coolant flow down.
You can also check the cooling fan operation by starting the engine and then turn the A/C on. That will force the fans to start.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
Read the cooling system sticky (top of the "general discussion" forum). Normal temp range is 190-230 F. That's why the C4 either has an oil cooler (L98 models) or requires synthetic oil (LT1/LT4 models).
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
Read the cooling system sticky (top of the "general discussion" forum). Normal temp range is 190-230 F. That's why the C4 either has an oil cooler (L98 models) or requires synthetic oil (LT1/LT4 models).
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
But the 195F stats were never above 197.
Burning Brakes
Joined: Jun 2016
Posts: 761
Likes: 66
From: Fitzwilliam New Hampshire
Clean rad. fins and ac condenser, usually full of sand, dirt, bugs, leaf particles, turn on defrost when temp starts to climb at slow speeds ,at stop for a long time, turns on fan before ecm.
Last edited by A Peter C4; Apr 24, 2017 at 11:39 PM.
Drifting
Joined: Feb 2008
Posts: 1,537
Likes: 177
From: NE Ohio
2024 C4 of the Year Finalist - Unmodified
A thermostat doesn't keep a engine from overheating it helps the engine get to operating temp sooner. Sounds like yours is doing what it is supposed to do
Advanced
Joined: Aug 2016
Posts: 95
Likes: 9
From: kent
Just to confirm what others have said.. I've been told several times these engines run hotter then others. My 86 holds steady at about 170 when on a run but climbs to 220/230 when idling in traffic,which is where the fan kicks in and brings it down a touch...I've also put a switch under the dash to manually switch the fan on via the relay if needed but never had to use it yet
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
Read the cooling system sticky (top of the "general discussion" forum). Normal temp range is 190-230 F. That's why the C4 either has an oil cooler (L98 models) or requires synthetic oil (LT1/LT4 models).
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
I'm not yet comfortable when the engine hits those temps either, but I'm slowly getting used to it.
Thread Starter
Advanced
Joined: Apr 2014
Posts: 75
Likes: 0
Ran car on open highway at 70 mph and temp ran over 220. I think it should run cooler. Can understand if when stooped in traffic on l hot day Think 220+ on open road is too hot?