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[C2] Overflow
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,205
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From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
Overflow
I filled the expansion tank half full and drove for about 30 minutes. After I shut the engine off, I could hear it percolating in the expansion tank followed by quite a bit of overflow. Now that the engine is cold, the level in the expansion tank is only about an inch.
Engine temp running 180-190 measured with IR gun. After shut down, temp rose to 210 which is close to boiling with a 50-50 anti-freeze. One inch in the expansion tank seems too low but if that's the level where it won't puke anymore
I suppose for this 327/300hp it's normal.
Thoughts,
Bud
Engine temp running 180-190 measured with IR gun. After shut down, temp rose to 210 which is close to boiling with a 50-50 anti-freeze. One inch in the expansion tank seems too low but if that's the level where it won't puke anymore
I suppose for this 327/300hp it's normal.
Thoughts,
Bud
Drifting
Joined: Apr 2011
Posts: 1,622
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From: Australia
The boiling point of coolant is around 260* with 15lbs of pressure, so 210* after you shut it off is really nothing to worry about.
So is this a new problem ? Did you change anything ? Has it been getting worse ?
So is this a new problem ? Did you change anything ? Has it been getting worse ?
Last edited by anyChevy; Nov 7, 2024 at 11:41 PM.
Le Mans Master
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Melting Slicks
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Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,205
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From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
I bought a replacement today from NAPA. It's super easy to remove unlike the one I had on. I haven't driven the car yet but the old one seems seal better than the new one. I have a Veterans Day parade Monday so that should be a good test. Only problem is the temp gauge doesn't work so steam or seizure will be my only indication the engine overheated.
Drifting
Joined: Apr 2011
Posts: 1,622
Likes: 398
From: Australia
I filled the expansion tank half full and drove for about 30 minutes. After I shut the engine off, I could hear it percolating in the expansion tank followed by quite a bit of overflow. Now that the engine is cold, the level in the expansion tank is only about an inch.
Leave the cap off and let it idle up to around 180 with your IR gun when the thermostat should be open.
Its possible there’s some air trapped somewhere, but you never said if this is a new problem, getting worse or you changed anything ?
If it starts to puke out coolant from the tank, shut it off.
If it doesn’t, put the cap on and see if if still looses coolant.
But having a non operating temp gauge in a stop start parade is a still bad idea.
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,205
Likes: 378
From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
When I got the car, I drove it about 150 miles. When I shut it down, I got a large puddle of coolant out of the overflow. I didn't refill it back to half full but after I got home, it didn't puke anymore out the overflow. It still had maybe an inch of coolant in the expansion tank. The ambient temperature for the parade is mid 60's so I'm hopeful it will survive.
Safety Car
Joined: Apr 2009
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From: Georgetown TX
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Carry an IR gun with you. Is timing set to spec?
Thread Starter
Burning Brakes
Joined: Jul 2014
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From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
Timing is spot on. The replacement cap does not seem like its making a good seal. I don't need to press down on it to rotate it open.While the book shows it's an exact fit for a '66, the old cap seemed to give a more positive seal. I'll try it tomorrow for the parade but I'll bring the old one along just in case even though it pissed out coolant with the old cap.
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 1,205
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From: Knoxville, TN
2020 C1 of the Year Finalist - Unmodified
New radiator cap worked. No more overflow grom the expansion tank.
The temp guage began working. Before the parade, it registered 180 and during the parade it went up to 210.
The temp guage began working. Before the parade, it registered 180 and during the parade it went up to 210.
Safety Car
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From: Georgetown TX
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Glad everything went okay. Most old Corvettes are not parade cars.