Coolant pushing past the radiator bleed screw

[MarkEJohnson]

I suspect I know the answer to this ... but I have coolant pushing past the plastic bleed screw on the top of my radiator (1991 318is) when it revs past idle.

I have replaced the o-ring because it appeared to be damaged, that didn't help. Replaced the whole screw, and that didn't help.

Looking at the threads in the radiator, they appear to be fine - but there is a small gap/crack at the top of the threads (where the o-ring would connect). It looks very even - like it's supposed to be there - but I'm guessing it isn't.

Can anyone confirm if there is supposed to be a gap/crack there? It is on the horizontal (top) surface, above the threads and is about 1/16th of an inch across, maybe smaller - just a little slice.

Thanks.

-mark

[romeomike]

I have the same gap -- points to the right -- no leaks.

Update: new aftermarket radiator -- no gap.

[MarkEJohnson]

I took off the cover that surrounds the bleed screw and the coolant fill cap and found a hairline crack on the rise around the bleed screw. I mixed up some expoxy, slid it into the crack and then squeezed it closed, making sure none ended up in the threads. After that dried, I built up a second layer on the outside and then reassembled. Has held for a few days now and my cooling issue is gone.

For now, at least ...

-mark

[CCR Engineering]

Mark, if it comes back let me know. I just put a Mishimoto radiator in my car and I've got the one that came out of my car. They're about $230 new from Orielly's if I remember right. Mine was working perfectly and there weren't any cracks around the bleed screw.