Author Topic: Bleeder screw on the radiator is stripped. What to do? (Read 5745 times)

a930rocket · « **on:** March 25, 2011, 04:53:25 PM »

Bleeder screw hole on the radiator is stripped. Figured this out when I was bleeding it. Anyone have a way of fixing it? Coolant was escaping past the o-ring until I teflon tape wrapped around the threaded portion, but don't feel it's a long term answer.

My other thought was to glue it there permanently with something.

Otherwise it's a new radiator from Pelican.

Thoughts?

pdxmotorhead · « **Reply #1 on:** March 25, 2011, 08:49:45 PM »

Plastic can be drilled and tapped if the tap is REALLY sharp lie brand new and you take little bites, mabe use a shouldered plug and go up a size?

Dave

EDIT Meant Plug not plg... arg//

a930rocket · « **Reply #2 on:** March 26, 2011, 02:09:57 AM »

What's a shouldered pig?

I may have messed up when the old screw broke and I used an easy out to remove the remains. I assumed it an open hole all the way down, but after looking inside, I noticed that there is a small shoulder in the left side of the hole. This may line up with the groove in the side of the screw to seal it. It looks like I knicked the shoulder, preventing a good seal at the bottom.

Maybe I need to fill the groove in, but will it tighten up, as it seems stripped. I'm leaning towards epoxying it in for now, but worry about bleeding it later. Can I use the radiator cap to bleed it?

jscribble · « **Reply #3 on:** March 26, 2011, 10:03:24 AM »

I sealed mine with rtv, then replaced the rad as soon as the weather improved. Got my by.

$200 bucks for a new radiator, with tank, cap and all hoses (with shipping iirc)

B318M42W · « **Reply #4 on:** March 26, 2011, 11:49:26 AM »

I'd consider trying to find a similar sized NPT male plug with a large flat head and just try to screw it in then depending on how much thread is left either get an O-ring or a really good RTV or can always try to use a solid ring as a spacer (like a bango bolt). NPT threads have a taper to them. Plastic is reletivly soft and you could manage to auto-tap it with the bolt. (or maybe drill it a little larger to get the bolt to fit better)

Just ideas...

a930rocket · « **Reply #5 on:** March 26, 2011, 02:41:02 PM »

RTV and a NPT plug are good ideas. I'd like to use something that I can remove to bleed the radiator.

jscribble · « **Reply #6 on:** March 26, 2011, 08:06:33 PM »

I know it isn't a good idea. The proper solution (for me at least) was to order new (low-cost!) radiator and hoses. I had a few bent fins, overspray, and a crappy seal on the integrated tank too though. I had no luck finding the piece that the bleeder screws into, but perhaps it is available.

a930rocket · « **Reply #7 on:** March 26, 2011, 08:27:29 PM »

From taking the end cover off and taking a look, the bleeder screw is part of the end tank. It can't be replaced and it's only so thick. Not enough meat to drill and tap fir the next size bolt. Plus the bolt wouldn't have the slot for bleeding and I screwed up the shoulder on the inside. The slot has no place to seal against.

jscribble · « **Reply #8 on:** March 26, 2011, 09:08:17 PM »

Here is the part, it just comes with some additional materials attached. I came to the same conclusion, and I wish I would have replaced it immediately, instead of jury-rigging a fix that later failed.

DesktopDave · « **Reply #9 on:** March 27, 2011, 11:52:54 AM »

jscribble, that link has too many http's! Here's the right one.

I'd suggest just going with the new radiator. I like saving a buck just as much as anyone else, but you're speaking about a surprising about of pressure and heat in the system. Any major leak could end the head gasket & likely the cyl head in a minute to two...$200 is cheap insurance in my mind.

There is also a brass replacement part made to replace those silly screws. I'm not sure it's a good fix if it'd make stripping the radiator a possibility. Now that I'm thinking about this problem, I wonder how difficult it'd be to install a conventional bleeder in the top of the radiator?

But, if you're dumb like me, I'll share my recent experiences. Things I'd avoid: no brass brake bleeder fittings (brass and epoxy gave me some grief); no metal filled epoxies like JB Weld (chemical contamination if I had to guess).

I did successfully use some great SEM body panel epoxy and high-temp vac black nylon barb fittings to temporarily repair my 325i's radiator bleed pipe. I had to go to a paint & body shop to get the good stuff (picked it up with my annual quart of POR15.

The nylon in the end tanks will weld pretty easily with a powerful soldering gun. I'd estimate you'd want at least 50 watts. Be sure to fill it with nylon, not PP or PE...they won't handle the heat & pressure cycles for very long.

a930rocket · « **Reply #10 on:** March 27, 2011, 05:34:55 PM »

Dave,

Funny you mention an alternate bleeder screw in place of the old one. It might not be pretty, but it would work.

I'm going out tomorow to look for the bleedscrew and a NPT plug, then see what works best. I do have a bolt with the same ptich, but its head it too big. I'd have to grind it down to make it work, but I still have the problem with it being stripped.

I'll eventually get a new radiator, but I gotta go slow, as the CFO isn't happy with my spending money on it.