'72 cooling question

[vettenick]

I'm working on a '72 454. Can someone help me with the coolant refill procedure? If I fill the surge tank to within one inch, as soon as it starts to warm up, coolant starts coming out of the overflow hose. I lose about a quart, and then it stops. Am I missing something?
I checked the surge tank after it cooled off and I couldn't see anything. At that point the tank was empty.
Thanks!

 

[vettenick]

Thanks for the response!
I'll let you know.

 

[JohnZ]

By "surge tank" do you mean the radiator side tanks? '72 big-blocks didn't use a separate expansion/surge tank.

 

[vettenick]

There's one there. The car is original.

 

[JohnZ]

Most of my references are C2 - don't have a '72 JG; I stand corrected. According to Tom DeWitt, all '72 BB's used a 27.5" copper/brass-core radiator with side tanks and no separate expansion tank - his info must be in error.

 

[jim coulter]

My fact book by Mr. Dobbins shows a 72 big block with an expansion tank, so I quess thats right, but I wouldn't think fluid running out till the tank was empty would be right. Have you tried to run it with the cap off, to see if it circulates when the engine warms up and the t-stat opens. I wouldn't think it was just overfilled, or you would think it would run out till at the correct level, and then stop..thus leaving some coolant still in the tank.

 

[vettenick]

Thanks guys! I know there's a lot of uncertianty with these cars and I appreciate your opinion. I don't look at it being right or wrong. I guess that's why we're here.
As far as the overflow problem. I'll spend some time with it this weekend and report back. According to GM, the tank should be half full when cold. We'll see.

 

[GaryS]

I can't say for certain on your car, but the surge tank on my 66 had a note to only fill HALF WAY. That left room for expansion and to keep the coolant from running out, just as you described.

Try leaving it alone for a bit, drive it around and check when cool. If the level doesn't drop then you should be ok. Do you have an owner's manual? It should tell you the proper level.
Gary

 

[vettenick]

Thanks GARYS! What motor do you have in that bryar blue car?
That's one of my favorite colors.

 

[vettenick]

I took the car out for 2 hours today in an ambient temp. of 80 degrees. The car ran fine. After the car cooled off somewhat, I checked the expansion tank and it was half full....go figure.
Thanks to all who posted!