Over heating problem
Thread Starter
Racer
Joined: Mar 2012
Posts: 476
Likes: 37
From: Lynnwood WA
Over heating problem
Ok, here's the deal. I have a 79 C3 with a 350 with TPI and a 700R4. A few weeks ago it started overheating on the freeway, as soon as I got onto surface streets it would cool off immediately. Now it has progressed to overheating whenever I am moving no mater what speed I am going. It just starts running hotter and hotter. If I just sit still either in or out of drive it stays cool, I can start the car put my foot on the brake put it in gear and it never overheats. I have replaced the weather stripping around the radiator and between the hood and rad support. I have installed support springs in both radiator hoses, no leaks no air pocket in intake and my cooling fan is working fine! I spent days reading the post on overheating none helped. Any ideas?
Zorro
Zorro
Le Mans Master
Joined: Oct 2006
Posts: 6,842
Likes: 285
From: Palmdale CA
Tough one. You've put spring inserts in the hoses (but were they still good?) because if they felt like you were squeezing grandma's soft and flabby arm, I'd replace them.
You didn't mention if you looked for obstructions, like plastic bags and whatnot, but I imagine you have. Check the radiator cap too, because that will cause problems and finally, I'd do a pressure test on the radiator. You might have an unknown bigger problem, like cylinder heads, that might just be starting to rear it's ugly head, it just isn't obvious yet.
Another odd one, I found, are clogged exhausts. If the cat has collapsed, it may be hindering the flow of exhaust gases out and this will bump up the exhaust temperature, possibly causing the engine to overheat.
Tell us what you find, so we can add it to the 'tribal knowledge'!
Timing can cause this too! If the timing is too retarded, then the spark happens as the piston is starting to travel down and instead of the explosion happening at the top and the pressure is pushing it down, you have the mix being ignited as it moves down, transferring the excess heat to the cylinder walls and into the cooling system. I've had this happen myself.
You didn't mention if you looked for obstructions, like plastic bags and whatnot, but I imagine you have. Check the radiator cap too, because that will cause problems and finally, I'd do a pressure test on the radiator. You might have an unknown bigger problem, like cylinder heads, that might just be starting to rear it's ugly head, it just isn't obvious yet.
Another odd one, I found, are clogged exhausts. If the cat has collapsed, it may be hindering the flow of exhaust gases out and this will bump up the exhaust temperature, possibly causing the engine to overheat.
Tell us what you find, so we can add it to the 'tribal knowledge'!
Timing can cause this too! If the timing is too retarded, then the spark happens as the piston is starting to travel down and instead of the explosion happening at the top and the pressure is pushing it down, you have the mix being ignited as it moves down, transferring the excess heat to the cylinder walls and into the cooling system. I've had this happen myself.
Last edited by F22; Mar 6, 2014 at 05:29 PM. Reason: Added timing info
Thread Starter
Racer
Joined: Mar 2012
Posts: 476
Likes: 37
From: Lynnwood WA
Thanks
Zorro
Thread Starter
Racer
Joined: Mar 2012
Posts: 476
Likes: 37
From: Lynnwood WA
Tough one. You've put spring inserts in the hoses (but were they still good?) because if they felt like you were squeezing grandma's soft and flabby arm, I'd replace them.
Hoses are new I put the springs in just to be sure that they were not the problem.
You didn't mention if you looked for obstructions, like plastic bags and whatnot, but I imagine you have. Check the radiator cap too, because that will cause problems and finally, I'd do a pressure test on the radiator. You might have an unknown bigger problem, like cylinder heads, that might just be starting to rear it's ugly head, it just isn't obvious yet.
No obstruction, new rad cap with pressure release, it has pressure. I think (hope) a head gasket would cause the motor to overheat at idle.
Another odd one, I found, are clogged exhausts. If the cat has collapsed, it may be hindering the flow of exhaust gases out and this will bump up the exhaust temperature, possibly causing the engine to overheat.
Headers with dual exhaust no cats no obstruction.
Tell us what you find, so we can add it to the 'tribal knowledge'!
Timing can cause this too! If the timing is too retarded, then the spark happens as the piston is starting to travel down and instead of the explosion happening at the top and the pressure is pushing it down, you have the mix being ignited as it moves down, transferring the excess heat to the cylinder walls and into the cooling system. I've had this happen myself.
Hoses are new I put the springs in just to be sure that they were not the problem.
You didn't mention if you looked for obstructions, like plastic bags and whatnot, but I imagine you have. Check the radiator cap too, because that will cause problems and finally, I'd do a pressure test on the radiator. You might have an unknown bigger problem, like cylinder heads, that might just be starting to rear it's ugly head, it just isn't obvious yet.
No obstruction, new rad cap with pressure release, it has pressure. I think (hope) a head gasket would cause the motor to overheat at idle.
Another odd one, I found, are clogged exhausts. If the cat has collapsed, it may be hindering the flow of exhaust gases out and this will bump up the exhaust temperature, possibly causing the engine to overheat.
Headers with dual exhaust no cats no obstruction.
Tell us what you find, so we can add it to the 'tribal knowledge'!
Timing can cause this too! If the timing is too retarded, then the spark happens as the piston is starting to travel down and instead of the explosion happening at the top and the pressure is pushing it down, you have the mix being ignited as it moves down, transferring the excess heat to the cylinder walls and into the cooling system. I've had this happen myself.
Thanks
Zorro
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Thread Starter
Racer
Joined: Mar 2012
Posts: 476
Likes: 37
From: Lynnwood WA
It's about a year old. It was really cheap, but it is not making any of those noises bad pumps make or leaking. It does pump water into the engine when I am refilling the system. One thing that I don't remember seeing before, is the water in the rad moves up and down as I fill things up but it is calm, no current or churning.
Thanks
Zorro
Thanks
Zorro
Drifting
Joined: Oct 2005
Posts: 1,331
Likes: 479
From: Appleton Wisconsin
It's about a year old. It was really cheap, but it is not making any of those noises bad pumps make or leaking. It does pump water into the engine when I am refilling the system. One thing that I don't remember seeing before, is the water in the rad moves up and down as I fill things up but it is calm, no current or churning.
Thanks
Zorro
Thanks
Zorro
Drifting
Joined: Jul 2004
Posts: 1,695
Likes: 64
From: Kissimmee fl
Finalist 2021 C3 of the Year - Modified
2017 C3 of Year Finalist
Cruise-In VIII Veteran
St. Jude Donor '07
It's about a year old. It was really cheap, but it is not making any of those noises bad pumps make or leaking. It does pump water into the engine when I am refilling the system. One thing that I don't remember seeing before, is the water in the rad moves up and down as I fill things up but it is calm, no current or churning.
Thanks
Zorro
Thanks
Zorro
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Instructor
Joined: Nov 2013
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Likes: 17
From: Pasadena MD