This happened to me. Changed oil about a month ago. Oil usage about "normal.", but a few days ago I noticed about a tablespoon of oil on my garage floor. Cleaned floor and same result after an overnight park. Bought a new oem aluminum drain plug with crush washer; and returned to my indy mechanic. He R&Red the drain plug. Old drain plug has a crack around one third of the rim. No doubt this was from over-tightened or possibly a casting defect. I've used this indy for fifteen years with no comebacks whatsoever until now. There was no charge for the R&R labor. I'm not sure the cause was over-tightening as the threads on the old plug look new without any distortion.

 

lucky the threads didn't strip! You don't need to tighten all that much - but it's annoying because if you go just a bit under it can leak too. Spec is something around 20ft-lbs, which isn't much.

 

It would have to be shocking over tightened to crack even an aluminum drain plug. More likely it was simply reused too many times and experienced too many heat cycles. I believe the aluminum drain plugs are technically considered a service item, and generally even for those who skip an oil change (or like me, change the oil on shorter intervals) you really shouldn't reuse the drain plug more than 2-3 times.

Paul

 

I had the same experience after my first oil change on a 2 year old CPO car. (oil drips)

I changed the AL crush gasket and torqued to spec -- no leaks initially but after a 900 mile trip the next day to Kansas -- it left a pretty good puddle on the in-laws driveway and a mess on the underbody cover.
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Turns out the plug had been overtorqued sometime in its previous usage --- was able to see the difference when put next to a new plug -- it was slightly stretched at the head/thread interface.

New plug, washer and oil at about 1000 mile interval done in driveway fixed the problem

I now change the plug every other oil change. (they are relatively cheap and I hate leaks)

 

Copper washers switch?

 

I do not use copper crush washers in this application for 3 reasons:

1. They are harder than the aluminum ones and do not crush the same as the AL washers at the same torque on the plug.
2. Trying to avoid dissimilar metal galvanic cell corrosion at the oil plug / sump / washer interface. (even though the bottom of the sump is painted, the threads are not)
3. Sticking to OEM recommended part (they are not that expensive) - and I do use a new one every time I remove the oil plug.

 

I would not have guessed copper harder to dent than Al.
Changing every oil change is definitely a must though.
Thanks.

 

Just changed the oil in ours. 30Nm for the plug (8mm hex, replace the aluminum gasket M18 size), 25 Nm for the filter cap, but the cap has an arrow from the 25Nm to SW 36 or some number close to that. Wonder if that means anything? 9.5 US quarts A40 0W-40 ('13 GTS if that matters), drove around some checked level on cluster and it's perfectly centered between Max and Min. Shear guard and large black panel damaged, going to pick them up Wed. hopefully.

 

I added a very light "smear" of silicon gasket maker to the threads of the oil plug, even though Porsche does not require this. No doubt this adds friction to the plug resulting in perhaps a distorted torque value, but I don't care. I have been changing oil on cars for over 65 years, and have never felt the need to use a torque wrench, even with cars that have aluminum pans. I tighten the plug to "snug", which has always worked for me. My drain plugs do not leak, seep, etc. one drop....