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Rubber oil drain plug?

Years (if not decades) ago I would sometimes come across a stripped oil drain. I could go to the local auto parts store and buy something that looked like the nipple on a baby bottle (but much thicker) to jam into the drain hole. It came with a special tool to expand the end as you inserted it. It worked great and I drove many many miles with those things.

Does anyone know if they still exist and/or where I could get one? They were a lot easier (and cheaper) than a helicoil. I’ve spent a lot of time googling for it and can’t find anything close.

They’re called expansion plugs and these things should only be used in an emergency until it can be fixed properly in my opinion.

A stripped drain plug does not need a Heli-Coil. Simply run a thread tap through it for an oversize drain plug. Some plugs are designed to even cut their own threads and in the event of a no-tap situation one can take a large Grade 8 bolt with the same thread pitch as the drain plug, grind a couple of V-notches on each side of the threaded end of the bolt, and use that as a thread tap.

Thanks for the reply, but that’s not it. I did come across expansion plugs and that isn’t the item I’m hoping to locate.

It is mentioned here:

When I was young and broke, I’d use these when necessary and drove a long way with them. They made a very good seal, were durable, and did not fall out.

I have seen the rubber stoppers in all the McParts stores on the HELP racks. They don’t seem to be a good repair but I would certainly use one to get me home where I could install an oversize plug.

Yeah they are still available…the most popular application is in the Marine environment… Outside that Sears Hardware ALWAYS has them in the nut and bolt section… They have a threaded rod (actually its a bolt immersed inside the rubber plug) there are external threads and a nut n washer …you tighten the nut and it expands squishes the rubber plug…and it expands uniformly…Work great…but dont use as the final solution. They are best used as bilge plugs

What you need to do when you come across a stripped out Oil pan is to intstall the next size up “Repair Plug”. This type of plug has a tapered tip and special Hardened threads with relief grooves cut into it (to allow shavings to escape) You then install this plug as though you were using a tap and die… It cuts its own oversized threads… 1/4 turn in… then back out…so on and so forth till she seats… This is a permanent repair… You can only do this oversizing say 2-3 X before you need to move to more drastic measures. The first go around should have you fixed up permanently.

Let me know if you need help finding this item… I use them all the time

FORGET about your rubber plug…They are for emergency use…and not to be trifled with as a perm solution.


The threaded-rod-with-some-rubber-on it isn’t what I’m looking for. It’s a gizmo that I put into a $100 Cadillac that I bought in Anchorage, drove down the then-unpaved Al-Can to San Diego, back up to Seattle, to Pennsylvania, and around PA for another year. The frame on the Caddy rotted away but the rubber plug was still in there. I would replace it as meager finances allowed.

I’ll try to attach a picture of it (I drew it in MS Paint).

Thanks for the replies. Since this item doesn’t seem to exist anymore I’ll hunt up an over-sized self-tapper.

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The style rubber plug that you drew in MSpaint is one that I saw used often back in the 70s. I personally used it my car for several years back then. Sometimes you’d get a very slow drip with them and the solution was to either put a new one in or try rotating it a bit.

I would listen to some of the previous replies you got in this thread on more stable fixes.

That device had some catchy name as I recall and was used in emergency (for me) situations. There’s a better solution (the one by ok4450, for example) than this . . I don’t think I’d even use it in an emergency, I’d call a tow truck and fix it properly. DO they still exist? I have not seen one in over 30 years . . . maybe you could follow Blackbird’s advice and look into marine applications. Since you’re here for advice as to where to find one I guess you have already decided to use that device and not solicit advice as to other methods of repair. Look marine. Rocketman

The device that I’m asking after was easy and reliable. Click & Clack agree with that assessment ( But since it’s not around anymore, I guess I’ll go looking for a metal/drill/tap solution.

OH…they exist still…forget what they are called…BUT WHY…do you want to go this route when you can buy one of the self tapping oversized STEEL plugs and be done with it FOREVER…or until you forget your own strength and overtighten it again.

These self tappers are a permanent solution and dont require you to use a tap n die to cut new threads…forget the rubber idea please…there are no advantages to it.

It seems to me that a 5 dollar self-tapping drain plug would be far superior compared to what will likely be a cheap hunk of inferior Chinese rubber.

Some may remember those disentegrating Chinese valve stems that led to some blowouts a few years back.

OK. I gave up and bought a M12 x 1.75 single oversize self tapper ($3), which leads to another question. What torque should I install it to? The original factory manual states 20 NM or 14.5 ft-lbs. Should I set the self-tapper to the same torque, or maybe a little less?

I’m with OK on this. I used one for years till I sold the car with nary a lost drop of oil. If or when it spins, go another size up, don’t be overly oncerned about the torque wrench. Obviously the original was over done. I just treated it like aluminum bolts and only wrist tightened when grounded. They will hold better then regular threads.

You can tighten it to your torque specs… On the other hand just be prudent and you can do it by the seat of your pants…dont over do it. Also make sure you have a nice new copper (or vinyl) drain plug washer installed on it as well.

I agree with everyone that an oversize tap & plug is much better, but the plug that you’re referring to I’ve heard called “boat plugs”…because they’re common on boats. The technical term is, as OK4450 said, expansion plugs. And they can be acquired at marine equipment stores. Although if you live in many parts of the midwest you may have a problem finding a marine equipment store.

Sears Hardware has the expansion plugs…I bought a few to keep water out of my Exhaust pipes when washing two identical Yamaha Banshees… they work like a charm for that…

If oversized plugs are installed with a plastic washer/seal, 8 - 10 ft lbs should keep them sealed if the oversize is a snug fit. Painting the threads with pipe sealing shellac and letting it dry prior to final assembly might assure that there is no leak and no vibrating loose.

I bought a single oversized drain bolt Dorman Brand) to repair a stripped drain plug in a Kia Rio. I have to work under the car and I can’t get the new plug to seat and begin cutting new threads. How do you get these things started?

What kind of plug did you buy? There are plain oversize plugs and there are oversize plugs that are designed to cut their own threads. Just trying to make sure you have the right widget.

The tip if the plug is tapered with four slots 1/8th deep, cut into the end of the plug… I dob,t know if your have to put alot of pressure on the plug while your trying to screw it in. I can’t get much pressure on the plug in the position I am working under the car. After multiple trys to seat the thing I tapped it lightly with rubber mallet but that didn’t help.