next troubleshooting step?
Thread Starter
Pro
Joined: Sep 2010
Posts: 535
Likes: 10
From: Fort Worth TX
next troubleshooting step?
Car is 2008 ls3 with 135,000 miles only engine mods are headers and exhaust.
3 weeks ago coolant overheated to 250+ in stop and go traffic. Problem diagnosed and fixed as faulty radiator fan control module.
800 miles later of normal operation coolant temperature spikes back up again to 250+, coolant overheating and spilling out everywhere.
When the engine is on, the coolant temp constantly rises to 250 at which point it's shut down. Coolant temperature rises from cold to 250 in about 20 minutes idling with a fan blowing into the intake, and cools back down quickly when shut off.
Thermostat and water pump have been replaced but problem still persists.
Even with radiator fan at high speed you cannot feel much airflow within the engine bay. Not sure if that is normal, but radiator was taken out looking for airflow blocking debris and found some internal buildup which was flushed out but unfortunately problem still persists.
Condenser checked and cleaned up same time radiator was.
Checked multiple times from start for any air in system and successfully pressure checked without any leaks
No visible leaks from under car, nor smoke from anywhere.
Car is not throwing any error codes
Any ideas?
3 weeks ago coolant overheated to 250+ in stop and go traffic. Problem diagnosed and fixed as faulty radiator fan control module.
800 miles later of normal operation coolant temperature spikes back up again to 250+, coolant overheating and spilling out everywhere.
When the engine is on, the coolant temp constantly rises to 250 at which point it's shut down. Coolant temperature rises from cold to 250 in about 20 minutes idling with a fan blowing into the intake, and cools back down quickly when shut off.
Thermostat and water pump have been replaced but problem still persists.
Even with radiator fan at high speed you cannot feel much airflow within the engine bay. Not sure if that is normal, but radiator was taken out looking for airflow blocking debris and found some internal buildup which was flushed out but unfortunately problem still persists.
Condenser checked and cleaned up same time radiator was.
Checked multiple times from start for any air in system and successfully pressure checked without any leaks
No visible leaks from under car, nor smoke from anywhere.
Car is not throwing any error codes
Any ideas?
Last edited by corvette-kyle; Jun 11, 2015 at 08:18 PM.
Racer
Joined: Mar 2015
Posts: 285
Likes: 6
Cannot count the number of radiators I have replaced on GM's. Techs blame everything from dexcool to the sealant pills that gm uses. Protect your investment, change your radiator.
The good news is these engines can handle a reasonable amount of overheating without permanent damage.
Good luck with repair. May want to consider an aftermarket part.
The good news is these engines can handle a reasonable amount of overheating without permanent damage.
Good luck with repair. May want to consider an aftermarket part.
Le Mans Master
Joined: Nov 2007
Posts: 6,415
Likes: 198
From: Wilkes-Barre Pa
Are you sure the fan is actually running at full speed? The fan connector isn't burnt?
Make sure there are no air pockets in the coolant system. They can be difficult to get out.
Are you sure your pump is functioning properly? I've recently had an overheating issue on a car because the water pump impeller was slipping on the shaft.
Make sure there are no air pockets in the coolant system. They can be difficult to get out.
Are you sure your pump is functioning properly? I've recently had an overheating issue on a car because the water pump impeller was slipping on the shaft.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Get the front end up on an incline and make sure the thermostat opens and do a few revs and steady RPM cycles to Burp the radiator. Look for the fluid to go low once the coolant replaces the air in the block, and refill with more coolant
