what psi radiator cap?

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Apr 1, 2011 | 10:31 AM

riverracer au

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Melting Slicks

Joined: Oct 2010

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From: "ɹǝpunuʍop", Adelaide, South Australia

what psi radiator cap?

'72 auto with a/c
what psi cap should i have on my radiator?
i know i dont have a recovery/expansion tank, but why not on a/c cars?
can i fit 1? any photo's? part # etc?
car sits on about 195f, constant
can fill to top, but when i check after a drive it's down bout 1-1/2"
no water in oil, no funny exhaust smell, plugs clean etc
thinking it's just by passing the cap
have a 'stant 16psi lever' type on at the moment
any thoughts?

thanks

Apr 1, 2011 | 11:05 AM

Easy Mike

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From: Southbound

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I believe it's a 15lb cap, but don't quote me on that.

The AC cars usually got the 4 row Harrision copper and brass radiator; these do not use a surge tank.

Fill to about an inch below the opening. This allows an expansion space. Over fill it and you will lose coolant.

Apr 1, 2011 | 11:18 AM

riverracer au

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Melting Slicks

Joined: Oct 2010

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From: "ɹǝpunuʍop", Adelaide, South Australia

Quote:

Originally Posted by Easy Mike

Fill to about an inch below the opening. This allows an expansion space. Over fill it and you will lose coolant.

maybe thats my problem
thanks

Apr 1, 2011 | 11:41 AM

Mike Ward

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Quote:

Originally Posted by Easy Mike

Fill to about an inch below the opening. This allows an expansion space. Over fill it and you will lose coolant.

There should be a marking on the outside of the radiator indicating the proper 'full' level.

Apr 1, 2011 | 03:33 PM

7T1vette

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From: Crossville TN

You need that extra 'air space' for the expansion of the hot coolant. If you have filled it and it 'puked' out the excess, you shouldn't need to do anything else.

Apr 1, 2011 | 04:13 PM

Easy Mike

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From: Southbound

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Quote:

Originally Posted by Mike Ward

There should be a marking on the outside of the radiator indicating the proper 'full' level.

Provided you are of an age where your vision allows you to see the mark.

Apr 3, 2011 | 07:07 PM

doctorgene

Drifting

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From: Kansas

I think Easy Mike is right on, 15 # cap is what they Recommend. Gene

Apr 4, 2011 | 02:40 AM

riverracer au

Thread Starter

Melting Slicks

Joined: Oct 2010

Posts: 2,276

Likes: 337

From: "ɹǝpunuʍop", Adelaide, South Australia

Quote:

Originally Posted by Mike Ward

There should be a marking on the outside of the radiator indicating the proper 'full' level.

wiped the outside of the radiator and found the writing on the side
can see about 3 or 4 rows of exposed tubes thru the cap
seems a long way down
guess it just seems like it is because of the angle it's on

all my other cars have had overflow/recovery tanks

thanks