Big Block Overheating Issues
Thread Starter
Racer
Joined: May 2007
Posts: 296
Likes: 4
From: London Ontario
Big Block Overheating Issues
I just put together a 427/390 engine with a roller cam and forged pistons. When driving it pumps coolant out the over flow (no catch can, its a '63) until it is too low on coolant and overheats. It has an aluminum water pump that is suppose to flow 30% more. I used copper head gaskets, new rad hoses, 160* stat. Any ideas? Thanks
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
You didn't mention if the car was originally a big block car. If not, and if you haven't already, you might want to consider a larger radiator. Sounds like you might not have enough capacity. You may also consider installing an overflow tank.
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
My car had this same issue of over heating and losing the coolant. It would do ok at hwy speed but not at a stop due to the low coolant level.
I went to Advance auto and rented their cooling system tester and confirmed my suspect that the radiator cap had lost its ability to pressurize the system.
Its a cheap fix and easy to test. I read that the cap has 3 seals that can fail independently of each other. My pressure seal had failed and this is a part that will wear out.
I went to Advance auto and rented their cooling system tester and confirmed my suspect that the radiator cap had lost its ability to pressurize the system.
Its a cheap fix and easy to test. I read that the cap has 3 seals that can fail independently of each other. My pressure seal had failed and this is a part that will wear out.
Thread Starter
Racer
Joined: May 2007
Posts: 296
Likes: 4
From: London Ontario
I was wondering about that but hadn't tested it. Its for my Dad's car so I'll let him borrow the cap of my car and see if that fixes it.
The car was not originally a big block car but it does have the big block rad in it. When the coolant is full it runs great, just above 160 (a little cold to me but Dad bought the stat) so it doesn't sound like a capacity problem to me.
The car was not originally a big block car but it does have the big block rad in it. When the coolant is full it runs great, just above 160 (a little cold to me but Dad bought the stat) so it doesn't sound like a capacity problem to me.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
My car had this same issue of over heating and losing the coolant. It would do ok at hwy speed but not at a stop due to the low coolant level.
I went to Advance auto and rented their cooling system tester and confirmed my suspect that the radiator cap had lost its ability to pressurize the system.
Its a cheap fix and easy to test. I read that the cap has 3 seals that can fail independently of each other. My pressure seal had failed and this is a part that will wear out.
I went to Advance auto and rented their cooling system tester and confirmed my suspect that the radiator cap had lost its ability to pressurize the system.
Its a cheap fix and easy to test. I read that the cap has 3 seals that can fail independently of each other. My pressure seal had failed and this is a part that will wear out.
Start with the cap and verify its condition.
Does the car run hot sitting in the driveway idling or just when driving?
Will it loose coolant when idling?
Neal
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