Topic: 1978 Trans Am Engine Cooling Question.. Help Needed

[Metallic Black 78 TA]

I traveled about 300 miles to pick up my 1978 Trans Am a few months ago. I honestly couldn't be happier with the purchase, however recently I've had some issues with the cooling system.

When I bought the car I inspected it from top to bottom and I can't find a spot of rust on this thing. The Carb needs rebuilt, but it's drivable comfortably. The engine has been fully rebuilt as I have pics of everything throughout. Living in Texas I went ahead and had the water pump replaced just for safety with a stock pump. (I had a 79 Z28 not too long ago and the water pump went and soon the engine)...

My radiator does look new and so do the hoses. I've installed a new thermostat and multiple radiator caps just to ensure that they weren't my problem.

My car while running does not overheat and doesn't even get close to it. Once I shut the car off however, a good amount of 50/50 begins to seep out of the radiator cap. I've tried to burp the system to remove any air, but it will still throw up some fluid. The car came with a "show type" overflow bottle and it honestly doesn't look like it can hold much of anything. I'm leaning towards that being my issue, not even space so the liquid just finds a way out.

Thoughts?

Any help would be very very appreciated.

Car Specs:                   1978 Trans Am
                                      Pontiac 400 Engine
                                    Automatic Transmission
                                      AC car
                                      Rebuilt Engine
                       Fort Worth Texas and 106 Degree Weather

[Tin Indians Rule]

Sounds normal to push out a little coolant once you shut it off. The coolant recovery jug is there for a reason. Its a closed system and pushing coolant into the jug is typical especially if you fill your system thru the radiator cap. Find your FILL line on the outside of the radiator tank. Do this when its cold as thats the FULL cold mark. Make sure you are full to that mark. Then look in your plastic coolant tank and fill to the FULL COLD mark. Drive the car and recheck. Unless your gauge is showing hot or you think the gauge is not working correctly then its perfectly normal to see some transfer between the radiator and coolant overflow bottle as they coolant inside the engine/radiator expand/contract as they heat/cool.

Post back if you have additional info.

[Tin Indians Rule]

PS welcome to the board and be sure to step over to the introduce yourself thread.

[Metallic Black 78 TA]

Im really trying to find a stock overflow tank instead of this show thing. If anyone has one for sale at a reasonable price, I'd be interested. Also the car doesn't even get close to overheating, its just really annoying that almost everytime I turn it off, it overflows itself.

 

[Tin Indians Rule]

Stock overflow bottles are less than 60 bucks brand spanking new from AMes or Performance Years. Brett can probably get you one too. Im sure some guys on here have a decnt used bottle for less than 20 bucks.