Author Topic: Radiator bleed screw issue? (Read 4988 times)

bullmand · « **on:** July 27, 2006, 12:57:30 PM »

Gentlemen,
I'm having some leakage around the radiator bleed screw. This became apparent after replacing the thermostat and it only leaks when the engine reaches the correct operating temperature as indicated by the halfway mark on the temp gauge. I've replaced the screw itself as the bottom of the old one had started to crumble. So, my question is about the threaded socket that the bleed screw screws into. It appears to have a split in it. I can't tell if it is supposed to be there or not. Given the leaking, I suspect not. I'll try to get a picture up here this weekend. Has anybody had a problem like this before? As far as I can tell from the parts diagrams, this socket is part of the whole radiator assembly. I'd rather not spend that money, so I'm thinking of trying some epoxy or sealant to get that crack sealed up. Opinions?
Thanks in advance.

BTW, the bottom of the bleed screw on my other BMW crumbled and broke a few days ago. If yours is original or you haven't messed with it in awhile I would check it.

silverblades181 · « **Reply #1 on:** July 27, 2006, 02:05:48 PM »

I've had that issue. First I thought the gaskets were shot and took the overflow out to discover that the bleeder screw socket was cracked. I sealed it off. Problem is you can't use the bleeder screw and you have to bleed your radiator from the overflow itself....it's pretty long and has to be done repeatadly for something like a week to get all the air out. Finally, the plastic holding the upper hose just cracked and fell off so I had to replace the radiator. It's 15 years old...and made of plastic, don't expect miracles, and be prepared to change it.

Edit: If you intend on using it as a Track rat or even Spec E30...just replace the radiator. A coolant leak while at 6500 rpm on a tight corner is the last thing you want.

bullmand · « **Reply #2 on:** July 27, 2006, 02:10:19 PM »

Thanks. We'll probably will replace it before we ever get it to a track. I want to keep this one working for a while and use our limited funds for stuff it really needs, like shocks and a clutch. Did you just plug it with epoxy or something?

D. Clay · « **Reply #3 on:** July 27, 2006, 02:31:54 PM »

I used JBWeld and put a small screw type hose clamp around the housing snugly. Put in the bleed screw and tightened it down and then tightened the hose clamp around the housing squishing the sealer out. Only problem is now it's IN permanent.
I bleed it by taking the upper hose loose and holding it up higher than the radiator inlet until I see coolant anf then stick it on real quick. Messy but quick.
http://fap99.com/

Nissen radiator is $142.

silverblades181 · « **Reply #4 on:** July 27, 2006, 02:33:11 PM »

Actually, I took it apart but my friend fixed it (we're both mechanics except I haven't finished my formation yet). I don't remember what the stuff was but it was red, I think it was urethane but I'm not sure. Could of been epoxy.

edit: yes it's sealed permanently though, I bleeded mine with the overflow tank. Long but not messy

bullmand · « **Reply #5 on:** July 27, 2006, 02:57:20 PM »

Cool. Thanks for the link. Those are great prices.

fabby318is · « **Reply #6 on:** July 27, 2006, 07:45:21 PM »

I just used some teflon tape on the threads of the bleed screw, worked like a charm.

bullmand · « **Reply #7 on:** July 27, 2006, 09:54:24 PM »

Quote from: fabby318is

I just used some teflon tape on the threads of the bleed screw, worked like a charm.

Did it really? I was going to try that, but it looked like that wouldn't be enough. I know what I'm doing tomorrow.

fabby318is · « **Reply #8 on:** July 28, 2006, 12:02:57 AM »

Trust me it actually worked.

Just make sure to apply at least a few layers of teflon tape to the bleed screw and take your time threading it back on.

bullmand · « **Reply #9 on:** July 28, 2006, 08:13:47 AM »

Cool. I'll let you know how it goes. Thanks.

bullmand · « **Reply #10 on:** August 01, 2006, 08:52:43 AM »

Update on this. The teflon tape didn't work. I discovered that the crack goes all the way through the plastic neck that the bleed screw screws into. There is good news however. I found a product called Magnum Steel that is a two-part putty. It was in the glue section at Lowes. You knead it together and then put it where you need it. The packaging says it can be drilled, tapped and machined once it hardens. So far, I've almost completely stopped the leak with this stuff. Eventually the radiator will need to be replaced, but I think this is going to work very nicely for a while.

bullmand · « **Reply #11 on:** August 31, 2006, 09:11:46 AM »

Update on this. After coming very close to overheating the car a couple of weeks ago, I sealed the bleed screw plug with that Magnum Steel stuff and it's been fine. New radiator, auxiliary fan switch and fan resistor go in today. I don't want to have to worry about this anymore.

M42boy · « **Reply #12 on:** September 04, 2006, 08:42:17 AM »

Quote from: fabby318is

I just used some teflon tape on the threads of the bleed screw, worked like a charm.

A new bleed screw is cheap.. I tried replacing mine, however, and couldn't figure out how to get it out!

For fear of breaking plastic parts, I decided to leave the old one in as it wasn't leaking yet.