What would be the solution to fix it? I have classical, easy to open it, when I'm opening drain bolt. The former owner torqued the drain bolt so tight I needed helper to open it for the first time. Now when I torque drain bolt to normal torque, I can open it back without any force. I have to add a quart of oil per month and I can see drops of oil below the drain plug and on the floor. How much I found there are five solutions

1) Try threads chaser M14-1,5 but I guess there are not many threads left.
2) Oversized drain plug M14-1,5 . How much I see problem with those is that they cut little of threads every time you pull them out and in for oil change.
3) Tap new thread of new size
4) Time-serts or Helicoil
5) New pan

At the moment I'm with nr 2. If it does not work can try nr 3.

 

??

what is normal torque?

The specified torque is 29LB-FT.

You also need to use a new aluminum crush washer every time you remove/retorque the drain plug. Are you?

Try that first before doing anything crazy.

A 3/8 torque wrench is $9.99 at harbor freight last I checked.

If you use 29LB-FT and a new crush washer, you'll find the drain plug pretty difficult to remove the next time you do an oil change. That is due to the prevailing friction caused by the crush washer. The plug is also steel going into an aluminum pan. Being difficult to remove is normal.

I'm pretty sure what you're doing is tightening it just barely snug or something. That's not how its designed to work.

There's probably nothing wrong with your threads.

 

^^^ Old owner overtightens it. Maybe he had an oil leak there since he overtightens it. Now I have enough threads to hold plug on but not to stop leaking. Can try longer bolt to.

 

I тap а new thread for the M14 bolt, it was enough for 5 oil changes, and it fell off again, maybe some special tap is needed for AlMg, I don’t know. The only thing that helped me was torch and press

I tightened it, measured how much oil was drained when changing it, and I don’t touch it anymore. Now during an oil change, I change the oil filter, then I pump out the old oil through the dipstick hole, about 3-5 fl.oz. remain in the engine, it suits me, it's still better than replacing the oil pan.

 

Ok sounds good.

 

I would tap it bigger and then install a fumoto valve of appropriate sizing

 

This is how I'm sure that it is bad threads in pan for drain plugs. At the beginning of the video, the guy talks about how drain plug open easily even if it is tightened properly. Exactly case at my Acura.


How much would it be worth to buy a longer bolt? The idea across Internet is that actual housing for drain bolt has more treads than drain plug and if you buy longer, you can catch threads dipper in pan that are not used so far. If true anyone knows how long is housing for drain bolt and how long bolt can be used.

 

One of the tricks it to get the mercedes drain plug. Same thread size but longer, so it will engage those 2-3 threads left. However that won't work for long, even if being religious with torque wrench.

Best to replace oil pan, second best are thread inserts like heli-coil, easiest one is to get one of those ~$30 kits from Amazon with M15 bolts. They come with tap, bunch of plugs, and gaskets.
Only issue about retapping to M15 is that when you strip those threads then probably only new oil pan is left and you have unusual size of gaskets. Helicoil gives you stronger threads than factory plug, and you can still use factory sized gaskets.

I don't like any of those cone shaped, self tapping, or rubber plug type repairs. A lot of them are more of temporary fix.

 

I replaced my pan, mine wasnt leaking but had one of the plugs that has butterfly drywall anchor that secures in the pan.

 

Great idea, poor execution, this rubber plug does not inspire confidence, it is interesting to read reviews after several years of use.