Drain Plug Loose and Leaking

DrRod · Sep 17, 2015

So I'm changing the oil in my Honda 450 ES and while replacing the drain plug it just turns and turns and turns. Doesn't seem to be cross threaded, it just won't get tight. I can wiggle it a little and it drips a little. I will confess that when it came out it fell into the space between the skid plate and the oil pan and I had to really fish around to get it out.

I took it back out this morning and restarted it in the hole and am pretty sure its not cross threaded. But still won't get tight.

So did I lose a gasket or washer, or did I cross thread it the first time and damage the hole? Or something else?

GPintheMitten · Sep 17, 2015

Was there possibly an O-ring on there that got lost when you dropped it on the skid plate?

DrRod · Sep 17, 2015

That sounds like a good possibility.

dusty3030 · Sep 17, 2015

Those have an O ring if I remember right.

RandyT · Sep 17, 2015

Honda normally uses a flat aluminum washer on the drain plug to act as a seal. Should still tighten down even without the washer, but will normally leak without the washer.

Sodo · Sep 17, 2015

When you say it turns and turns and turns,,,

1) The o-ring could be preventing it from catching a thread. Can you slide the o-ring into its proper location and get it to catch a thread? The drain plug should thread all the way in by hand (NO WRENCH).

2) Sometimes there is gunk in the threads (sediment), especially on horizontal drain plugs. This can be alarming, depending what it is (metal shavings?). Clean out the threads by twisting (threading) a paper towel into the hole. If thiere are metal shavings on the paper towel take a pic and post it.

3) If the plug is screwed all the way in, and it turns and turns and turns, its probably stripped. This is a bigger problem. A Honda shop will charge $1000 minimum, maybe more. I'd take it to an independent shop if that's the case and tell them you want one of these 3 options:
a) May be able to fix the thread with a helicoil
b) maybe you can re-thread to the next larger size and put in a larger drain plug.
c) maybe you can re-thread with a pipe-tap and use a "brass pipe plug" with teflon tape.

All of #3) require a higher level of mechanical ability and experience. The HONDA shop may have this experience but don't generally operate like that, they will offer the method that restores it to HONDA new. If you are the guy who stripped the hole then you probably can't do the 3a,b,c but it can be done quickly and cheaply with experience and proper tools. 3a and 3b will retain higher resale value of the 450ES if it's still valuable, or if you are worried about that. 3c would be the cheapest by far and a very good repair, absolutely acceptable and reliable.

Lets hope its #1.

DrRod · Sep 17, 2015

Yes - I'm hoping for the O-ring option. I'll back out the plug again [as soon as I get a clean oil catch pan -- don't need to waste another batch of oil] and see if the ring is there. I'm guessing its not -- given the amount of effort I spent chasing it around the skid plate, I wouldn't doubt that it fell off.

Should it not be the ring, I have a local repair place that is used to making-do with country engineering solutions. So with any luck they can make something fit.

Thank you all for your comments.

DrRod · Sep 22, 2015

And the answer is: the washer on the drain plug was missing. $1 at the dealer's parts department and we are all fixed. Think horses not zebras I guess. Thanks again for your help.