Corner of oil pan leaking slightly
 

Gents,

Happy New Year to All, and best wishes for a safe and prosperous 2020.

The driver's side front corner of the oil pan is weeping a bit of oil. I'm positive it's not the front main seal--the oil is localized. Should I just tighten the bolts in that corner, or should I remove, clean, and put new sealant on before tightening?

Thanks,

Tighten the bolts first obviously.
cuz resealing the oil pan is more of a pain in the peepee than it sounds.

Agreed

Just to be clear, I meant removing one bolt, cleaning the threads, applying new sealant to the bolt threads, installing it and torquing to spec. Then, if necessary, doing a second bolt the same way.

You don’t need to put sealant on the bolts, or at least you shouldn’t have to. You can just tighten the bolts, but there isn’t really a gasket to squish, just improperly installed RTV, which will still be improperly installed. It’s worth a shot but most likely you’ll want to pull the motor and reseal the pan.

This engine is a low mileage part-out and has about 80k on it now. I plan to run it into the ground. I suspect with proper care I can get another season out of her. I have a rebuilt engine waiting in the garage, forged pistons and rods, ARP, Volvo valve springs, etc., but I have decided not to remove the current engine as long as it's still making good power.
The seeping isn't bad. Although it is visibly noticeable, she doesn't eat a lot of oil.

Gents,
I figured this would happen--neither of the bolts in the front corner were actually "loose". They're tight up to 95 inch pounds. Any suggestions on how to proceed? I don't want to make things worse.
Thanks,

You have about 4 options:
1) leave it alone and deal with the leak
2) drop the front subframe and then the pan to reseal it
3) pull the motor out and reseal the pan
4) put your built motor in it now

#2 is the worst option in my opinion but I have done it before to swap out oil pumps.

Thanks.
I choose Alternative 1) for right now. It should be readily apparent if it starts getting worse, which would lead directly to 4).

One question... Did this engine previously have AC? If so, when the cast AC compressor bracket was removed from the block there were 5 bolts, 4 from the side of the block and 1 that passed through the AC bracket, the Oil Pump then into the front of the block casting (this bolt runs parallel to the crank). When the AC compressor bracket is removed, you need to insert a new (shorter) bolt to fasten the Oil Pump onto the front of the block. If you do not, then oil will seep out between the oil pump housing and the front of the block.
I had the same problem and found the above solution in an MT build thread about ~2011 or 2012...

Yes, it did have a/c, and no, I did not add a shorter bolt. I'll check that out. THANKS!

If you search miata.net you can find the exact size you need bolt you need. I have found them at Ace hardware several times without issue. It had just been a few years since I last replaced mine, so I am not sure on the size.

M8x1.25x45mm is what the thread calls for. If I recall, I used a 50mm bolt and put a crush washer under the head. No leaks for 4 years now.

Not my pic but this is the bolt that should be there.
https://cimg1.ibsrv.net/gimg/www.mia...a148a724fd.jpg

Beat me to it. Thanks for the picture!

Here's the link to the thread, if anyone else is interested. https://forum.miata.net/vb/showthread.php?t=407514 .

That's the bolt needed (great choice of photo).

Check you don't have a bolt that is too long or it will bottom out (in the threaded hole) before it has any clamping force on the Oil pump. (the old bolt is too long).

Thanks to 99Racer for this insight.

I just pulled the AC on mine, and did not think about that bolt needing to go back in. I might have caught it when I put the oil pan back on, but maybe not.

And thanks for the thread we were linked to, it mentioned one of the bolts pulled was already the right length, and indeed it was.