My radiator drain has a slow leak, even after replacing the old plug (94 Accord LX). I tightened it as far as felt safe (finger tight + pliers) but it still leaks. Can that thing be overtightened? Any recommendations on stopping the leak? I will try a couple of wraps of teflon tape tomorrow. Would a gob of vaseline or the rings or thread sealant be good (I don't want to contaminate coolant system)?

Thanks for your help and sorry if this has been answered elsewhere - I couldn't find it.

 

Borrow a pressure tester to make sure it really is the drain plug and not the lower end tank (which sometimes leaks about 1/4" above the drain plug).

If you've established that it is indeed the drain plug, change the radiator.
If you find that it's the end tank, change the radiator.
If you're unsure, change the radiator anyway... no, jk, if you're unsure, take it to a mechanic.

 

Hi Slomofo,
I watched the drain closely when it was up on jacks and the coolant is coming from inside the drain hole. I am *really* hoping for a fix that doesn't require a new radiator.

 

You can try teflon tape if you want or if you want to go ghetto style, you could JB weld it shut or use silicone or something and never remove the drain plug again. I don't know, I'm not experienced in MacGyver engineering, but I'm guessing that's what he would do.

 

Several wraps of teflon tape over the o-ring did the trick ! I had some waterproof putty to seal the whole thing up if the tape didn't work.

Aside: The old drain plug was painted black. When I took it off I figured it was just a non-oem plug. I think they noticed the radiator plug leak during my last flush and glued or screwed it on extra tight and painted the plug to say - " don't remove"

Thanks for your help!

 

When I was replacing my old leaky radiator with a new OEM one, I noticed too that the drain plug was painted black -- that's how they come from the factory.

If you already tried replacing the drain plug and the o-ring with the new OEM ones, and it continued on leaking until you wrapped it up in teflon (and you shouldn't need pliers for sure!), I would personally suggest looking for a new radiator because it probably means that your radiator's lower tank is deteriorating. These things are not meant to last for ever, you know.

 

Does anybody have a picture that shows the exact location of the radiator drain plug?

Also, where's the purge valve that lets the air out in the coolant system (for refilling after a complete drain)?

Thanks in advance for your help.