overheating issues
Burning Brakes
Joined: Aug 2005
Posts: 1,009
Likes: 2
From: Arkansas
I recently changed replaced the coolant with fresh Dexcool on my 5 year old C6 and ran into a similar problem when I started the car for the first time after refilling the system. Within a few seconds the fan was roaring and the DIC said to check coolant level.
What I finally figured out may be old news to some but I'll repeat it in case it helps someone. My system wouldn't self bleed with the fill cap unscrewed from the expansion reservoir. I had to fill the tank, put on the cap tight and run the motor for about 30 seconds, then cut off the motor remove the cap and top off the tank. After I did that about 4 times the system was fine. This might not be the problem for the OP since he has a modified car but it could help someone who can't get the air out of a stock vehicle.
What I finally figured out may be old news to some but I'll repeat it in case it helps someone. My system wouldn't self bleed with the fill cap unscrewed from the expansion reservoir. I had to fill the tank, put on the cap tight and run the motor for about 30 seconds, then cut off the motor remove the cap and top off the tank. After I did that about 4 times the system was fine. This might not be the problem for the OP since he has a modified car but it could help someone who can't get the air out of a stock vehicle.
Thread Starter
Race Director
Joined: Dec 2000
Posts: 14,697
Likes: 584
From: Sioux Falls SD
dale i will try that tomorrow.
also dkal how can i test the cap besides making sure it is on tight??
got a compression test so will do that if any of the above dont help.
thanks for the suggestions so far.
also dkal how can i test the cap besides making sure it is on tight??
got a compression test so will do that if any of the above dont help.
thanks for the suggestions so far.
Racer
Joined: Jul 2007
Posts: 303
Likes: 1
From: Houston Texas
Surge tank pressure cap is inexpensive, unless you have access to a pressure tester I would replace the pressure cap.
Pressure cap protects the cooling system parts by relieving excessive pressure that builds up under operating temps and vaccuum that occurs during cooling system cool down.
I would say if the pressure cap is not allowing the cooling system to operate at normal pressures the coolant's boiling point will be much lower.
If there is excessive pressure present in the system there is obviously a problem that has to be diagnosed.
A compression test should reveal any head gasket problems. However it can also reveal other engine problems too.
Hope you don't have other issues.
Pressure cap protects the cooling system parts by relieving excessive pressure that builds up under operating temps and vaccuum that occurs during cooling system cool down.
I would say if the pressure cap is not allowing the cooling system to operate at normal pressures the coolant's boiling point will be much lower.
If there is excessive pressure present in the system there is obviously a problem that has to be diagnosed.
A compression test should reveal any head gasket problems. However it can also reveal other engine problems too.
Hope you don't have other issues.
Racer
Joined: Jul 2007
Posts: 303
Likes: 1
From: Houston Texas
If you can't find one at the parts store, maybe you can invite one of your vette buddies over and borrow use theirs as test.
If it can only be that easy of a fix would be nice. Is the ect sensor okay? I know someone asked that question. Did the engine get hot enough where a code was set?
If it can only be that easy of a fix would be nice. Is the ect sensor okay? I know someone asked that question. Did the engine get hot enough where a code was set?
Thread Starter
Race Director
Joined: Dec 2000
Posts: 14,697
Likes: 584
From: Sioux Falls SD
If you can't find one at the parts store, maybe you can invite one of your vette buddies over and borrow use theirs as test.
If it can only be that easy of a fix would be nice. Is the ect sensor okay? I know someone asked that question. Did the engine get hot enough where a code was set?
If it can only be that easy of a fix would be nice. Is the ect sensor okay? I know someone asked that question. Did the engine get hot enough where a code was set?
also yeah it gave me the general change engine oil message came up on dic after it got hot.
damn my cts-v only uses a 15psi cap
Last edited by dvandentop; Jul 4, 2010 at 12:06 AM.
Burning Brakes
Joined: Aug 2008
Posts: 802
Likes: 6
From: Oro Valley AZ
Go to a shop that can do a BG flush. This will assure that the system has been purged of any air and should the system pressure drop below normal would indicate that water is escaping somewhere.
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Team Owner
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St. Jude Donor '15
"In honor of jpee"
Thread Starter
Race Director
Joined: Dec 2000
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From: Sioux Falls SD
Le Mans Master
Joined: Feb 2006
Posts: 5,762
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From: Chandler Arizona
the coolant line you are talking about goes right by the throttle body right?
where do i blow into the tank? also do i have the cap off during this??
Tdewit that is really hard to see the difference in the 2 pics besides a few bent fins on the radiator. so you are saying with the car running before the fans turn on a piece of paper should stick to the rad?
where do i blow into the tank? also do i have the cap off during this??
Tdewit that is really hard to see the difference in the 2 pics besides a few bent fins on the radiator. so you are saying with the car running before the fans turn on a piece of paper should stick to the rad?
Thread Starter
Race Director
Joined: Dec 2000
Posts: 14,697
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From: Sioux Falls SD
thanks for the info, today i drilled a 1/8 hole in the thermostat side/ (old racers trick) and then also took a garden hose and blew a hard blast of water til i saw it come out the other exit hole of the radiator.
put it all back together and filled it up and it did start to not run as hot, who knows maybe something was blocking the flow in the rad but it seems to be cooling better now.
need to do a test drive as i havent had any time to do that yet. so time will tell.
thanks for the info
put it all back together and filled it up and it did start to not run as hot, who knows maybe something was blocking the flow in the rad but it seems to be cooling better now.
need to do a test drive as i havent had any time to do that yet. so time will tell.
thanks for the info
Le Mans Master
Joined: Feb 2000
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I'm going to offer a "left field" option. Do you happen to be running your car with a bra on? I had the stretch thin nylon bra on my nose on my trip down to Bowling Green in May and my car was overheating - normal highway driving, nothing hard. Took the bra off and everything went back to normal. Haven't run with it since.
Just my .02.
Just my .02.