Rick's Free Auto Repair Advice

Repair a stripped oil drain plug

Options to repair a stripped oil drain plug

Overtighten the oil drain plug and you can strip the threads out of the oil pan. Once that happen, you’ll leak oil. Here are the four options to repair a stripped drain plug.

Expanding rubber oil drain plug

Several companies make a rubber oil drain plug that rubber oil drain plugfit into the oil pan opening and expands as you tighten the hex nut. They’re cheap, but they don’t last. They’re a temporary fix. Yeah, they’ll get you out of a jamb. Never count on a rubber plug for the long term.

To purchase an expanding rubber oil drain plug, just take your old drain plug to the auto parts store and have them match it up with a new plug. OR, refer to this oil drain plug size chart

Self Tapping Oversize drain plug

An oversize drain plug is a combination drain plug and tap that cuts new threads into your existing oil pan. You simply start the new plug into the old thread and tighten. The tapered end literally

oversize oil drain plug

Dorman Brand Oversize Oil Drain Plug

cuts new threads into the oil pan and the upper portion of the bolt seals against the pan. Does it work? Yes. Does it last? Yes, but only for about 6 oil changes. Here’s why:

1.      To work properly, the oversized drain plug must be perfectly square to the stripped opening. If it’s not, the new bolt head won’t sit flush with your oil pan and it won’t seal.

2.      It cuts shallow threads. To retap a hole properly, you really need to drill out the old threads and use a tap that cuts deep enough into the metal to make real threads. An oversize drain plug simply doesn’t cut deep enough threads. It’s a temporary fix.

Helicoil insert for new oil pan drain plug

A helicoil is a great way to fix stripped threads. You drill the stripped threads out, tap threads into the new hole, then thread in the heli-coil. This method works for most applications. But it isn’t the best solution for oil drain plugs. Here’s why. The helicoil is constantly submerged in oil. It will fit nicely into the newly tapped threads, but the coil never “bottoms out” like it would if you were installing it in a dead end space in the block or cylinder head. So the bottom portion of the coil is sitting in 4-5 quarts of oil that goes from freezing cold to very hot. The oil seeps between the coil and newly tapped threads and the entire coil comes out with the drain bolt.

JB Weld and oversize oil pan drain plug

I see this a lot on forums. Guys use the oversize bolt to tap new threads. Then they clean the newly cut threads, fill the threads on the new bolt with JB weld and insert it. The theory is that the epoxy fills in the gaps. Personally, I think this is a stupid idea. I’d rather fix it right the first time.

Install an insert for a new oil pan drain plug

This costs most than the other methods but provides

timesert oil drain pan plug kit

TimeSert Oil pan drain plug kit

a permanent solution. The kit comes with a drill bit, tap and insert. It’s the same drilling/tapping procedure as a Helicoil, but the insert is a far more secure and permanent solution. This is what I recommend.

Before you can buy a TimeSert kit, you’ll need

to know the size of your oil pan drain plug. See this chart to find the size

Replace the oil pan

This is the best but most costly solution.

Things to keep in mind.

An oil leak from the drain plug can cause your engine to run dry. That will destroy your engine.

If do a cheap fix, you risk destroying your engine.

Do it right or don’t do it at all

©, 2019 Rick Muscoplat

Posted on by Rick Muscoplat

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