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Stripped oil pan hole

I have changed the oil pan gasket on my 98 wrangler 4.0 and now am the proud owner of a stripped hole in the block for the front left pan hole. Do I need to pull the whole pan back off to tap the hole, or can I go through the current pan if I’m careful. Helicoil or tap? any info is great.


Have you tried using a thread chaser to see if the threads can be repaired?

Ace hardware sells this set.,0&resMode=sharp&op_usm=0.9,0.5,0,0

You wouldn’t need to remove the pan.


You can go through the existing hole if you’re careful.
Tap. If you decide on a helicoil, the hole in the pan may not be lareg enough and you’ll have to remove the pan.

Anytime you run a tap in a sensitive area - oil pan - coat the tap with grease first. It tends to capture the metal chips allowing you to minimize trash in the pan. This holds true for a thread chaser or a heli-coil tap.

Or try the fix outlined in this article;

The oil drain plug threads aren’t stripped.

One of the mounting holes for the oil pan to engine block is stripped.


thanks for the info, I try and not screw it up any more than I already have

This is excellent advice.
“Dry cutting” metal should only be done in very specific and unusual circumstances. Metal cutting tools should always be lubricated. The grease, because it tends to capture the chips, is an excellent way to do a blind hole like this. I might go for a thin grease, like silicone grease (available in any plumbing department).

This article describes the difference between tapping a stripped hole, and chasing a stripped hole.


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Unless a thread chaser works for you, I would simply replace the pan. By the time you spend $40 for a Helicoil kit and appropriate drill bit, you might as well get a new pan for around $55.

Edit: Forget it…I can’t read correctly

I read this as the threads in the block are damaged and the pan is fine.


Don’t you people read these post?

The drain plug threads aren’t stripped!

One of the holes for a bolt on the engine block that holds the oil pan to the block is stripped!



The thread chaser idea is a good one to try first. There’s a pretty good chance it would work. Beyond that, if I had this particular problem I’d take the car to the local auto machine shop. They’d be able to fix it straight-away without any drama and I expect the fee would be pretty reasonable.


Tester, great article…explains a lot for the simple mind like me who doesn’t deal with this often. GeorgeSanJose, i like your suggestion and might be a route I go if the chaser doesn’t work.

Next question: with one screw missing, is it ok to fill with oil and drive? any damage done, or maybe just some leaking?

Please don’t drive the vehicle if the oil pan is leaking. Use the suggested steps above and fix the problem.

It’s hard to say, without knowing how much it leaks. If the engine is run with little to no oil it will be quickly ruined. What you want to avoid at this point is resorting to overtightening any of the other screws to prevent a leak from the missing screw part of the gasket. Don’t make what is now a minor problem into a major problem.

Torquing the bolts is an important part of not screwing up the pan, It will probably leak, may be minimal may be massive.


Unless the pan is warped I don’t see one missing bolt as being critical and causing an oil leak. Drive it a ways and then recheck for any oil leak. Over the years I’ve seen leak-free oil pans, valve covers, and so on that were missing a bolt or two.

As a pure, backyard, stop gap measure you could run a short lag screw into the hole as that is dirt cheap and easy.
Odds are that would be good for the duration but should serve its purpose until when and if a proper repair can be made.


You’ll need to keep a close eye on your oil level.
Engines don’t die or sustain damage because they have an oil leak. They die or sustain damage because the owner doesn’t monitor the oil level and it drops below the level of the oil pump’s pickup tube, causing loss of lubrication. Their lives can also be shortened if they’re continually operated with low oil. A given amount of dilution is more damaging mixed into two quarts of oil than it is mixed into four quarts of oil.

The oil (lubrication) system is not a totally pressurized system. It operates by the pump pulling oil from the “pool” in the oil pan and pushing it through the spaces between the bearings and their wear surfaces. That forcing of the oil through the oil channels causes pressurization of that portion of the system, but once the oil has performed its function it drains down back into the pan to be reused. Pressurization of the crankcase is only a byproduct of normal “blowby”, which comes from combustion gasses being forced past the rings and pressurizing the crankcase. That pressure is normally dealt with by the Positive Crankcase Ventilation system allowing the pressure to be relieved and the gasses reprocess by the engine.

You can run the engine with one screw missing, but you need to monitor the oil level and ensure it doesn’t run low. However it’s always better to chase he hole and repair it. Note while dong that this is a “blind hole”, meaning it’ll bottom out, and not a “through hole”. Don’t force the tap when it hits bottom. You can measure its depth by inserting something into it and marking how far it goes, but consider this only a guide and not definitive. The threads will not go totally to the hole’s bottom, so it the depth measures at .500", it may only be threaded .490", so don’t force things.

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thanks for all the advice. I have a chaser on the way in the mail, which is my first resort.

The barn door is closed now but a thread chaser can be made with a standard bolt. Simply file 2 V-notches 180 degrees apart in the end of the bolt threads and run it in.

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