John92LT1

Since replacing the motor & cooling system on the '79, I have had a problem with coolant splashing out of the expansion tank during, um, "spirited driving." I would like to prevent this as it is making a mess of the now clean, painted (and free of oil leaks!) right side of the motor. The stock tank & cap has a 1/4" or so hole in the top, leading to an open raised area which the coolant can easily splash through. Am I missing a stock gasket or something? Any ideas on the best way to prevent this? I am thinking of some sort of disengagement or demister which would still allow the tank to breath.

Oddly enough this was never a problem before the motor & cooing system swap, as there was never any coolant in the tank, and the level in to old, corroded radiator just slowly, steadily dropped on its own...

John

MelWff

when completely cold is your radiator totally full and the expansion tank level is at the cold mark?
have you pressure tested your radiator cap?
what engine temperate are you seeing when your are doing a "spirited drive"?

John92LT1

The level is fine, with radiator full and level at the cold mark in the overflow. When warm, raising the hood as soon as I stop the car, the level is still fine. The issue seems to be splashing out the nearly open 1/4 hole in the top of the overflow tank cap when cornering/braking/accelerating hard. That is why I am thinking that something is missing to prevent the splashing.

I have not tested the cap (I think this is unrelated), but she is holding what I would consider good temperatures, with no real loss of fluid. She'll run ~210F moving, with the temp rising to ~218 in heavy stop and go traffic in the 95+F humid Houston summer, with the Vintage Air running.

KapsSA

Correct 79 cap is non vented as pictured.....
You probably have a generic replacement.

Paul L

I was thinking the same thing. I drove a 1979 for many years and there was never a 1/4" hole in the cap....

Metalhead140

X3, no hole in my cap.