Re-tapping Oil Pan

[atalarico]

Hey all,

So I've found a lot of decent info on what to do when you strip your oil drain plug and realize that the threads in the oil pan may be damaged. Not all of them are damaged because I've always been able to get the plug back in tight enough not to leak, but there is a point at which the plug would end up just spinning once it got to a certain tightness.

There seems to be less consensus about re-tapping. I got a M12x1.25 plug tap and double-checked with the company (drillsandcutters.com) that it will work for my 97's oil pan. I *really* don't want to take my oil pan off because it seems like a bigger job and I've been reading different ways to re-tap the threads without dropping the pan.

A few methods I've read in order of what I feel might actually work.
1.) Pour the oil you just drained out back through the engine to wash out the shavings (not turning your engine on in the process obviously).

2.) Grease the threads of the tap to catch any metal shavings and back the tap back out after every few good turns.

3.) Use a powerful magnet to draw out any metal shavings or a pen magnet to go into the drain hole. I'm less convinced of this one, but I'm not totally discounting it either.

What do you guys think? Any other people have any experience they'd like to share?

Also, was I supposed to buy a larger size tap (like an m13 or 14)? Am I overthinking this and can I just use something like this M12x1.75 self tapping magnetic plug? I know our plugs are m12x1.25, so that's why I didn't really consider any 1.75 options, but I suppose .5" (is the length measured in inches or mm?! It would make sense if it was mm considering it's a metric, but that's definitely not a 1.25mm long bolt...because that would be tiny) longer isn't going to kill me, right?

Thanks!

 

[nevada]

Hey all,

So I've found a lot of decent info on what to do when you strip your oil drain plug and realize that the threads in the oil pan may be damaged. Not all of them are damaged because I've always been able to get the plug back in tight enough not to leak, but there is a point at which the plug would end up just spinning once it got to a certain tightness.

There seems to be less consensus about re-tapping. I got a M12x1.25 plug tap and double-checked with the company (drillsandcutters.com) that it will work for my 97's oil pan. I *really* don't want to take my oil pan off because it seems like a bigger job and I've been reading different ways to re-tap the threads without dropping the pan.

A few methods I've read in order of what I feel might actually work.
1.) Pour the oil you just drained out back through the engine to wash out the shavings (not turning your engine on in the process obviously).

2.) Grease the threads of the tap to catch any metal shavings and back the tap back out after every few good turns.

3.) Use a powerful magnet to draw out any metal shavings or a pen magnet to go into the drain hole. I'm less convinced of this one, but I'm not totally discounting it either.

What do you guys think? Any other people have any experience they'd like to share?

Also, was I supposed to buy a larger size tap (like an m13 or 14)? Am I overthinking this and can I just use something like this M12x1.75 self tapping magnetic plug? I know our plugs are m12x1.25, so that's why I didn't really consider any 1.75 options, but I suppose .5" (is the length measured in inches or mm?! It would make sense if it was mm considering it's a metric, but that's definitely not a 1.25mm long bolt...because that would be tiny) longer isn't going to kill me, right?

Thanks!

they sell repair plugs for just this situation. they are upsized slightly, and meant to be used if the hole gets stripped out. ive used a few on different rigs over the years with good results. I imagine any decent auto parts store has, or can get them.

 

[atalarico]

they sell repair plugs for just this situation. they are upsized slightly, and meant to be used if the hole gets stripped out. ive used a few on different rigs over the years with good results. I imagine any decent auto parts store has, or can get them.

Good to know. I get the feeling that's what the plug in the link I posted might be for, no? It's self-tapping, magnetic, and says something about slightly oversized threads.

Let me know if that'll do the trick and I'll just go pick that up instead of messing around with this $15 tap I just bought. If it is, and it is magnetic, I'm going to screw it in once, back it out and clean it off, and then see if a regular plug will go back in.

 

[Fermin4Runner]

I have purchases an oversize plug from aftermarket for a Silverado I have and worked perfect for many years.
Looking for a tap just a little bigger on the same range of threads and re-tapping will work perfect and grease or any other method for the chip will work fine. Just do not blow the chips in with compressed air.
A friend with a lathe can make a plug from a bigger screw with same threads per inch and customize to you size in the oil pan. Takes time but it works. I have a lathe so I have done this also myself.
Good luck, Wilson

 

[MStudt]

You can also place a magnet on the tap itself, and it'll hold onto the chips.

 

[atalarico]

Crap, I realized that the second number of these bolts is the thread pitch not the length, right? So using the oversized plug that is m12x1.75 instead of a 1.25 is not a good idea, right?

 

[JohnJMonroe]

Crap, I realized that the second number of these bolts is the thread pitch not the length, right? So using the oversized plug that is m12x1.75 instead of a 1.25 is not a good idea, right?

Yes the 1.25 number is thread pitch. You need a bigger M number.

 

[atalarico]

So, I went ahead and tried the tap anyway. I greased the threads of the tap, was very careful to keep the tap level, and started turning. Oil was pouring down the little flutes in the tap, along with metallic shards. I went in about as far as I thought the drain plug normally goes and then backed off. I got some good resistance toward the end, so I knew it was working.

I took a pen magnet and picked up the metal bits from inside, but I think the oil coming out did most of the trick.

Not sure what to expect, I started threading the new drain plug in (normal m12x1.25 not the 1.75 one I got) and it went in well and tightened without issue.

Pretty happy this worked. The tap I got from drillsandcutters was about $15 shipped, and the tap handle was about $10.

Thanks for the help everybody!

 

[jd_adventuresquad]

So, I went ahead and tried the tap anyway. I greased the threads of the tap, was very careful to keep the tap level, and started turning. Oil was pouring down the little flutes in the tap, along with metallic shards. I went in about as far as I thought the drain plug normally goes and then backed off. I got some good resistance toward the end, so I knew it was working.

I took a pen magnet and picked up the metal bits from inside, but I think the oil coming out did most of the trick.

Not sure what to expect, I started threading the new drain plug in (normal m12x1.25 not the 1.75 one I got) and it went in well and tightened without issue.

Pretty happy this worked. The tap I got from drillsandcutters was about $15 shipped, and the tap handle was about $10.

Thanks for the help everybody!

just came across this same problem.. so what size tap did u use exactly. sorry I'm not to mechanically inclined.. right now I'm just using silicone to stop the leaking

 

[atalarico]

just came across this same problem.. so what size tap did u use exactly. sorry I'm not to mechanically inclined.. right now I'm just using silicone to stop the leaking

Hi! I used an M12x1.25 tap from drillsandcutters.com. I made sure to do the tap while there was still oil draining, and I think it worked out well, as the oil acted as a cutting oil, and I watched the metal shavings come down the flutes of the tap itself.

I then followed up with a pen magnet and bent it a bit to reach around the inside of the oil pan as best I could. I pulled out a fair amount of shavings the first few times.

Obviously it's best to pull the pan off to do this, but I'm not convinced it's not entirely necessary if you're extremely careful to get all of the shavings, and you're not really cutting new threads and just cleaning up the existing ones.

Cheers!

 

[atalarico]

Interesting, maybe concerning, update;

I was topping off my front diff and decided to check my oil pan drain plug. It definitely was a bit looser than I recall. I retightened it, but I didn't use my Craftsman click torque wrench because I hear they lie, and a oil pan drain plug isn't exactly super critical to be exact.

That was last week, so I'm going to check again today and make sure it's still snug. I haven't noticed any drips or puddles underneath, so it was probably just not tight enough the first go around because I was afraid of stripping it again.

If it is lose again, what should I be concerned with? I vaguely recall reading there is a nut at the end of the threads in that bolt hole. Does that maybe have something to do with it?

 

[gamefreakgc]

Interesting, maybe concerning, update;

I was topping off my front diff and decided to check my oil pan drain plug. It definitely was a bit looser than I recall. I retightened it, but I didn't use my Craftsman click torque wrench because I hear they lie, and a oil pan drain plug isn't exactly super critical to be exact.

That was last week, so I'm going to check again today and make sure it's still snug. I haven't noticed any drips or puddles underneath, so it was probably just not tight enough the first go around because I was afraid of stripping it again.

If it is lose again, what should I be concerned with? I vaguely recall reading there is a nut at the end of the threads in that bolt hole. Does that maybe have something to do with it?

You could always add a washer. I think the original drain plug has a soft aluminum or copper washer. If you are not excited about torquing it enough to bend a metal washer go down to a NAPA store and get an O-ring rubber gasket to fit over the bolt. Tada!

 

[atalarico]

You could always add a washer. I think the original drain plug has a soft aluminum or copper washer. If you are not excited about torquing it enough to bend a metal washer go down to a NAPA store and get an O-ring rubber gasket to fit over the bolt. Tada!

I have to double-check, but I'm 99% I didn't forget to replace the washer. It's part of my standard op procedure with changing my oil. Ya never know though...