[ToniCipriani]

So I took my car in to get its "pre-purchase" inspection (bad mistake, should've done it before I bought it), they found an oil leak.

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Right now looking at a drain plug and an oil sensor and then closely monitor it... Anything else could be a cause for the N20?

[F30ed]

Looks as a leak is from the plug. Could be simply loose or bad gasket, simple replace will fix.
Worse if someone over tightened the plug damaging the thread. It is plastic and needs very controlled hand tight to 18 lb/f (if I remember right). If that is damaged, that you need oil pan replacement. Not the end of the world, but will cost a few hundred I guess.

[ToniCipriani]

Originally Posted by F30ed

Looks as a leak is from the plug. Could be simply loose or bad gasket, simple replace will fix.
Worse if someone over tightened the plug damaging the thread. It is plastic and needs very controlled hand tight to 18 lb/f (if I remember right). If that is damaged, that you need oil pan replacement. Not the end of the world, but will cost a few hundred I guess.

I wouldn't be surprised if someone overtightened something... I just hope the dealer with cover it.

I guess at a few hundred I'm still ahead on what the BMW dealers here wanted for a CPO, that leak and one bent rim were the only bad news out of the PPI.

[ToniCipriani]

So I gave it some thought, this diagnostic replacement order seem to make sense?

Oil Drain Plug + Sensor Gasket -> Sensor -> Oil Pan

I'm actually not too convinced the sensor is bad, it seems to be detecting the level just fine.

[Billfitz]

If it isn't broken don't fix it. The gasket is the likely culprit.

[ToniCipriani]

Originally Posted by Billfitz

If it isn't broken don't fix it. The gasket is the likely culprit.

Hopefully that's it...

Used car lot took it up and gave me a new gasket plus drain plug. It was actually seeping out at the sensor when they took the under shield out.

[Polo08816]

Originally Posted by Billfitz

If it isn't broken don't fix it. The gasket is the likely culprit.

Nothing a light coat of Flexseal couldn't fix.

[ToniCipriani]

So just an update on this... car lot took it up, and gave me a new sensor seal and drain plug. Hopefully that sorts it out.