Overheat.....HELP
Thread Starter
Pro
Joined: Nov 1999
Posts: 659
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From: Woodland Ca
Overheat.....HELP
I'm flushing the radiator after breaking in a rebuilt engine.
I've put on 600 miles and ran just H2O in case of any problems. No over heating problems with the water and first 600 miles. New thermostat, high freeway temp. has been 200-205 degrees or so.
I used the drain plug on the side of the radiator to drain the water. Closed it, put flush and water in it and go on the road.
Somewhere between 5 and 10 mins, the temp went right up to 299 and stayed. The over fill tank was full...I had put about 3/4 full of water in it and it was leaking out. When I opened the radiator cap I could not see any water.
I emptied the overfill tank, turned the engine on and added more water to it. It went right from 240- 299 degrees.
Don't want to let it run too long because I don't want to warp the heads.
Any thoughts PLEASE!!!!!!!
Thanks
I've put on 600 miles and ran just H2O in case of any problems. No over heating problems with the water and first 600 miles. New thermostat, high freeway temp. has been 200-205 degrees or so.
I used the drain plug on the side of the radiator to drain the water. Closed it, put flush and water in it and go on the road.
Somewhere between 5 and 10 mins, the temp went right up to 299 and stayed. The over fill tank was full...I had put about 3/4 full of water in it and it was leaking out. When I opened the radiator cap I could not see any water.
I emptied the overfill tank, turned the engine on and added more water to it. It went right from 240- 299 degrees.
Don't want to let it run too long because I don't want to warp the heads.
Any thoughts PLEASE!!!!!!!
Thanks
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheat.....HELP (BIG K)
It could be an exhaust head gasket leaking into the coolant stream. It would seem strange that the leak would occur simultaneously with a radiator flush. If the overflow bottle is overflowing, it might be the result of exhaust gases forcing the coolant out. There are several checks: with the coolant system full, engine on, fill cap off, you might see bubbles exiting the fill neck of the fill tank. After the engine is heated and cooled down, there will be pressure evident when you remove the fill cap. The syphon of the overflow bottle will not occur due to the pressure built up by the exhaust gases. Lets's hope this is meaningless info....good luck.
Your year vette may not have a separate fill tank. If not, you would see bubbles exiting the radiator with the cap off, if there was a leak in the exhaust head gasket.
[Modified by Oldman, 4:25 PM 5/4/2003]
Your year vette may not have a separate fill tank. If not, you would see bubbles exiting the radiator with the cap off, if there was a leak in the exhaust head gasket.
[Modified by Oldman, 4:25 PM 5/4/2003]
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheat.....HELP (BIG K)
If you didn't go through a re-torque procedure on the heads after the 500 mile break-in, it is possible that torquing the heads may seal an exhaust leak, assuming the gasket is OK.
Excuse a basic question, but were the heads surfaced before the assembly?
[Modified by Oldman, 7:03 PM 5/4/2003]
Excuse a basic question, but were the heads surfaced before the assembly?
[Modified by Oldman, 7:03 PM 5/4/2003]
Thread Starter
Pro
Joined: Nov 1999
Posts: 659
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From: Woodland Ca
Re: Overheat.....HELP (Oldman)
Thanks for the quick responces Guys! Let me see if I can anwser all the questions.
The water pump and the thermostat were brand new as I did a rebuilt. I had the engine sent to Jasper's and they did a complete rebuilt(including heads), therfore I can't answer your question about if the heads were surfaced.
I would like to think that the water pump and the thermostat are still good. I would like to find out more about "air lock"...could someone go more into detail about what to look for and what to do about it?
It apears that I missed the retorking of the heads.
At what point do I need to do this?
The overfill tank was already almost full after I emptied it and added the flush kit. But I did noticed that there was quite a bit of bubbling into the overfow tank.
Thanks again!!!
The water pump and the thermostat were brand new as I did a rebuilt. I had the engine sent to Jasper's and they did a complete rebuilt(including heads), therfore I can't answer your question about if the heads were surfaced.
I would like to think that the water pump and the thermostat are still good. I would like to find out more about "air lock"...could someone go more into detail about what to look for and what to do about it?
It apears that I missed the retorking of the heads.
At what point do I need to do this?
The overfill tank was already almost full after I emptied it and added the flush kit. But I did noticed that there was quite a bit of bubbling into the overfow tank.
Thanks again!!!
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheat.....HELP (BIG K)
Let's assume that Jasper's resurfaced the heads for flatness.
Torquing the heads again should be done now.
I would bet against an air lock as your problem. An air lock would cause over heating, but not the displacement of coolant.
The symptoms all point to an exhaust leak into the coolant stream. Rapid excessive heat, displacement of coolant, overflowing recovery bottle, etc. You probably haven't had time to let the engine cool down and remove the radiator cap. If there is pressure in the coolant system when you remove the cap with the engine cold, you no longer have a closed system, allowing coolant to syphon back from the recovery bottle.
My suggestion would be to torque the head bolts, fill the system with water, turn on the engine with the radiator cap off, and look for bubbles after the water temp has opened the thermostat.
Torquing the heads again should be done now.
I would bet against an air lock as your problem. An air lock would cause over heating, but not the displacement of coolant.
The symptoms all point to an exhaust leak into the coolant stream. Rapid excessive heat, displacement of coolant, overflowing recovery bottle, etc. You probably haven't had time to let the engine cool down and remove the radiator cap. If there is pressure in the coolant system when you remove the cap with the engine cold, you no longer have a closed system, allowing coolant to syphon back from the recovery bottle.
My suggestion would be to torque the head bolts, fill the system with water, turn on the engine with the radiator cap off, and look for bubbles after the water temp has opened the thermostat.
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Thread Starter
Pro
Joined: Nov 1999
Posts: 659
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From: Woodland Ca
Re: Overheat.....HELP (Oldman)
Would you believe that I forgot to run the heater during the flush?
I turned the heater on after "burping the radiator"...squezing on the upper radiator hose. Was able to add a gallon of water. The temp came down to 240 degrees, and the low coolant light finally came on.
Maybe their's not enough water in the system?
I turned the heater on after "burping the radiator"...squezing on the upper radiator hose. Was able to add a gallon of water. The temp came down to 240 degrees, and the low coolant light finally came on.
Maybe their's not enough water in the system?
Le Mans Master
Joined: Jul 2001
Posts: 8,181
Likes: 3
From: Santa Maria, CA
Re: Overheat.....HELP (BIG K)
Use distilled water too.
Retorque can be done after a heat cycle or two. Fel-pro permatorque gaskets claim not to need a retorque. Maintain communication with Jasper's and apprise them of what is going on. In case something is wrong, they will be in the loop.
Retorque can be done after a heat cycle or two. Fel-pro permatorque gaskets claim not to need a retorque. Maintain communication with Jasper's and apprise them of what is going on. In case something is wrong, they will be in the loop.
Team Owner
Joined: Jan 2003
Posts: 20,254
Likes: 221
From: Summerland B.C. Canada
Re: Overheat.....HELP (BIG K)
I did the TB bypass yesterday and after that my coolant temp went higher than normal.I didn't worry because all i did was the TB bypass.My answer to the high reading is i might have got an air lock and the sending unit might have been dry for a period of time.I added coolant and went for a drive with some good rpm to move some fluid around.After that the temp returned to normal.This hopefully is your problem too. Good Luck!!
Thread Starter
Pro
Joined: Nov 1999
Posts: 659
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From: Woodland Ca
Re: Overheat.....HELP (AGENT 86)
I think you are right. The job of flushing the radiator is a longer process than in other vehicles.
I'm thinking of putting in a flush kit next time... the kind that you cut into the heater hose. I understand that "backflushing" is better anyway.
Why did you go with the TP bypass, AGENT 86?
I'm thinking of putting in a flush kit next time... the kind that you cut into the heater hose. I understand that "backflushing" is better anyway.
Why did you go with the TP bypass, AGENT 86?
