Can’t stop the heat
Thread Starter
Cruising
Joined: Jul 2019
Posts: 13
Likes: 0
From: Decatur Georgia
Can’t stop the heat
I own a 89 c4 corvette...I have replaced & cleaned everything in the cooling system ...yet it’s still running 253 at high speeds ...but at idle it runs 161 ...I’ve heard several different opinions from fuel injectors to retarded timing to bad computer module ...& air in the system ...I need help ...I’m about to give up on this car
Thread Starter
Cruising
Joined: Jul 2019
Posts: 13
Likes: 0
From: Decatur Georgia
I’ve blown a head gasket & just had it replaced...plus replaced the thermostat water pump hose & radiator ...cleaned out the area between the radiator & ac condenser ...I’ve got $2000 in this car in repairs & it’s still running hot ...
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Thermostat, wrong water.pump, garbage blocking condenser, garbage between condenser and radiator, radiator tanks filled with crud restricting flow. Heating up at + 40 MPH thermostat, radiator, or airflow thru radiator.
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Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Ok so it sounds like you have done all the right things replacing the major components.
To see if the water pump is basically working, when the engine is cold, remove the radiator cap. Then look in as rev the engine slightly. You should see some flow of coolant. If it's completely still might be a flow problem. When it comes up to temperature, see if both radiator hoses are about equally hot.
Team Owner
Joined: Sep 2001
Posts: 62,161
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Something is wrong with the water flow, in that its not flowing.
Stock thermostat should open at 195F, if you don't see the temps pause at that temp and hover around it, then its stuck.
Verify fans are operating main fan at 228, any pusher in front about 10F higher.
Open the rad cap at startup and verify that coolant is flowing once the t-stat is open. You'll definitely see it. Pull the throttle back once it starts bubbling out of the cap and that will suck it down, you'll see the flow. That will at least tell you whether the WP is moving anything or that there is a blockage.
If its only happening at speed, then there is an airflow issue over the radiator, something is blocking that. C4s get hot at idle but at speed the temps should drop into the 200-215 range.
Stock thermostat should open at 195F, if you don't see the temps pause at that temp and hover around it, then its stuck.
Verify fans are operating main fan at 228, any pusher in front about 10F higher.
Open the rad cap at startup and verify that coolant is flowing once the t-stat is open. You'll definitely see it. Pull the throttle back once it starts bubbling out of the cap and that will suck it down, you'll see the flow. That will at least tell you whether the WP is moving anything or that there is a blockage.
If its only happening at speed, then there is an airflow issue over the radiator, something is blocking that. C4s get hot at idle but at speed the temps should drop into the 200-215 range.
Race Director
Joined: Oct 2008
Posts: 19,234
Likes: 1,672
From: Long Island
collapsed lower radiator hose, common problem
go with a 160 stat.
Clogged radiator, lower sections are full of leak stop. - have it boiled.
Wrong fan and it's running backwards. Not blowing air through the rad toward the motor.
Missing front air dam.
go with a 160 stat.
Clogged radiator, lower sections are full of leak stop. - have it boiled.
Wrong fan and it's running backwards. Not blowing air through the rad toward the motor.
Missing front air dam.
Team Owner
Joined: Sep 2001
Posts: 62,161
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019