overheating problem in my c3
Thread Starter
4th Gear
Joined: Sep 2010
Posts: 4
Likes: 0
overheating problem in my c3
ive got a 1975 thats overheating. car overheating very quickly, within a few minutes temp is upwards of 230 reaching as high as 250 or so and coolant is boiling out of the radiator. after i turn the engine off, temperature continues to climb for another 15 degrees or so before it tops off and starts to cool. have a dual fan aftermarket radiator, fans are working. don't have a tstat, oil seems fine, completely stumped as to what the next move is.
Burning Brakes
Joined: Sep 2008
Posts: 805
Likes: 5
From: Naperville Illinois
In addition to good advice above: Check your lower hose to make sure it isn't collapsing. Check your timing (read the sticky at the top of this thread). Re-install a quality 180 deg thermostat, but drill a 1/8" air bleed hole in the flange (search the Forum for info on this).
Burning Brakes
Joined: Dec 2007
Posts: 889
Likes: 0
???
Why does he "need" a theromostat? Unless the Corvette cooling system is an odd-ball, in my experience worst case with no thermostat is that the engine will run very cool - too cool for winter heat and it will take a long time for the choke to shut off.
BTW: did it start running hot after a mod or repair? How long has the engine been running in the configuration you described?
BTW: did it start running hot after a mod or repair? How long has the engine been running in the configuration you described?
Race Director
Joined: Jun 2000
Posts: 10,039
Likes: 670
From: FL
Need more info. Highway or idling.
If overheating while idling, you have an issue with the fans not pulling air through the radiator.
If overheating on the highway (greater than 40mph cruise), fans are not a factor. Do you have all the radiator seals to stop air from bypassing the radiator.
Also, what is the condition of your waterpump and hoses. It is possible that your lower hose is collapsing, preventing flow.
Also, no reason not to run a thermostat. They just control the lower temp of the system, decrease warmup time, and prevent excessive wear. I like a 180 stat myself.
If overheating while idling, you have an issue with the fans not pulling air through the radiator.
If overheating on the highway (greater than 40mph cruise), fans are not a factor. Do you have all the radiator seals to stop air from bypassing the radiator.
Also, what is the condition of your waterpump and hoses. It is possible that your lower hose is collapsing, preventing flow.
Also, no reason not to run a thermostat. They just control the lower temp of the system, decrease warmup time, and prevent excessive wear. I like a 180 stat myself.
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Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Why does he "need" a theromostat? Unless the Corvette cooling system is an odd-ball, in my experience worst case with no thermostat is that the engine will run very cool - too cool for winter heat and it will take a long time for the choke to shut off.
BTW: did it start running hot after a mod or repair? How long has the engine been running in the configuration you described?
BTW: did it start running hot after a mod or repair? How long has the engine been running in the configuration you described?
Instructor
Joined: Aug 2006
Posts: 104
Likes: 0
From: Apache Junction Arizona
My high heat problems went on for a while..
1) New radiator cap - no change.
2) Checked air dams under nose, ensure proper air flow - no problems.
3) Replaced radiator foam seals- no change
4) Installed high flow water pump - No change.
5) High flow t-state - no change.
6) New OEM radiator - little chance.
7) After market fan to replace the OEM electric fan - little change.
8) Water Wetter - little change.
9) 100% glyco.... - bad idea! (50/50 now)
10) Aluminum radiator w/dual fans - some change - not good enough! WTF!!
11) Installed correct gauge wiring to the new dual fans - FIXED!!
I made the mistake of using the OEM electric fan wiring harness for the new duals, which pulls 40+ amps, these new fans were running at half their available CFM flow. When I installed the manufacturers wire harness for these fans, the high heat (240 degrees) and over heat (250+) went away!
I am lucky I did not burn up my 82 as the OEM harness started to melt! Lesson learned - always use the correct gauge wiring!
I live in Arizona and at the time of all of this, my 82 was a daily driver and in the summer, with the AC on, +110 degrees outside, in traffic - I now do not see more than 215 degrees in these harsh conditions! Normal temps now runs at 180 to 190.
Good Luck!
1) New radiator cap - no change.
2) Checked air dams under nose, ensure proper air flow - no problems.
3) Replaced radiator foam seals- no change
4) Installed high flow water pump - No change.
5) High flow t-state - no change.
6) New OEM radiator - little chance.
7) After market fan to replace the OEM electric fan - little change.
8) Water Wetter - little change.
9) 100% glyco.... - bad idea! (50/50 now)
10) Aluminum radiator w/dual fans - some change - not good enough! WTF!!
11) Installed correct gauge wiring to the new dual fans - FIXED!!
I made the mistake of using the OEM electric fan wiring harness for the new duals, which pulls 40+ amps, these new fans were running at half their available CFM flow. When I installed the manufacturers wire harness for these fans, the high heat (240 degrees) and over heat (250+) went away!
I am lucky I did not burn up my 82 as the OEM harness started to melt! Lesson learned - always use the correct gauge wiring!
I live in Arizona and at the time of all of this, my 82 was a daily driver and in the summer, with the AC on, +110 degrees outside, in traffic - I now do not see more than 215 degrees in these harsh conditions! Normal temps now runs at 180 to 190.
Good Luck!
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
what kind of fans do you have? pushers? pullers? , are they located in front or rear of the radiator?
Advanced
Joined: Mar 2006
Posts: 76
Likes: 0
From: brigantine nj
drilling a 1/8 hole
In addition to good advice above: Check your lower hose to make sure it isn't collapsing. Check your timing (read the sticky at the top of this thread). Re-install a quality 180 deg thermostat, but drill a 1/8" air bleed hole in the flange (search the Forum for info on this).
Intermediate
Joined: Apr 2009
Posts: 36
Likes: 0
the 1/8" hole is if you had a thermostat you drill a small hole through the thermostat, this lets a small amount of air or fluid through the thermostat making it much easier to get all the air out of the system.
Makes bleeding much simpler.
Makes bleeding much simpler.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Do you have a stock radiator, cap and coolant recovery tank installed? It's normal for some coolant to pushed out of the rad to the tank when the car is at normal temps.
Have you verified the accuracy of the gauge?
Have you verified the accuracy of the gauge?
Drifting
Joined: Sep 2010
Posts: 1,412
Likes: 50
From: Laguna Niguel California
Just a few quick thoughts - one guy on another forum had problems with overheating because his engine builder put the wrong head gaskets on, 400 on a 350 or vice-versa. Also I'm not a believer in the electric fans, lots of people have had trouble with them. I run a direct fan on the waterpump, Stewart waterpump and Stewart drilled thermostat (160), original type brass 4-core radiator and the temperature never gets over 180 even climbing a hill on a 95 degree day.
Thread Starter
4th Gear
Joined: Sep 2010
Posts: 4
Likes: 0
The car has electric fans which seem to be operating fine. I have checked the oil and the color seems to be fine, although I have read different descriptions of what the oil will look like when coolant has mixed. I added a 180 thermostat, started car and let it run for about 7 minutes or so today and the temp gauge never made it to 180 degrees and the coolant never began to circulate through the radiator. Problem is there was a steady stream of white smoke coming from the tailpipes which has yet to happen before. The smoke was very light and could not be seen when I tried to video for a friend to see.