Engine leaks only when running
 

Alright, so I just took the time to replace my crank seal and cam seals. Engine still leaks real bad. I even bought the FM installer tools to make sure they went in right, so I think I can eliminate the possibility that there's a problem there.

Today I parked the car and didn't have any oil drip out after shutting it off, maybe something small. Upon starting the engine and letting it idle for a couple min, there is a visible drip coming smack out the middle of the oil pan in the front. There's even a 1/4-inch wide 'stream' going right down the middle.

Discounting the possibility that I installed /another/ bad oil seal, and with the FM tools it's pretty obvious that they were installed correctly, is there the possibility that I have a bad oil pan seal? I replaced it when I put together the new motor, but I think I could have had a "new old stock" seal that's too old and doesn't seal well.

I don't believe RTV is to be applied to the oil pan gasket, correct?

The rear of the engine also leaks. At first I thought this was because I forgot to put thread sealant on the flywheel bolts or maybe I had a bad rear main seal, but considering the front AND the rear of the motor are leaking, the evidence further points to the oil pan seal again.

I'm considering pulling the motor AGAIN just to pull the pan and replace that gasket, as well as the rear main just to be safe. While I'm doing that, I might do a new clutch and 6-speed transmission. Yossi is selling a 3.6 and 6-speed set in the classifieds and while I don't want to pull out the checkbook again, it's looking very tempting.

yes you do apply it

Did the factory even use an oil pan gasket? IIRC my NA8 was just siliconed on. I think that's all I used when I put it back together as well.

There are the half moon seals on the front and rear of the engine.

On the motors I've taken apart, none of them had RTV on the gaskets.

Oooooh those little guys. They gets the sealant as well.

WHELP, maybe that's where I fucked up

But how come Mazda gets to get away with not needing to put sealant on those, but we have to?

My oil pan was glued on tight, with grey sealant from factory. It was a bitch to even get all the old sealer off. Used rtv all the way around when going back on. Don't know if the half moon seals are supposed to get it or not, but they did, and it's not leaking.

Well, here's my old engine, no RTV on the gasket except for the edges where it met the pan.

https://cimg2.ibsrv.net/gimg/www.mia...16a706cb39.jpg
https://cimg6.ibsrv.net/gimg/www.mia...76ba5278b4.jpg

Yes. What year oil pan? There are two different sized gaskets.

2002, I ordered it off of RockAuto and I got the right part number

For NB2, I always use OS30631R from rockauto. I've had others be the wrong size, even though they list it as compatible.

I had ordered Mahle OS32096. Is this the problem?

EDIT: Additionally, I recently ordered Fel-Pro OS30631R to replace the leaking gasket. However, realistically I need to pull the motor to do the gasket. It can be done with the engine in place, but it's such a pain in the ass I'd rather pull the motor and put it on a stand. Plus I can do the six-speed and clutch upgrade while I'm at it.

I've never ordered that brand, but I've had problems with beck arnley being the pre-01 gaskets, so I just stick with the one I know works.

Completely agree on pulling the engine.

For any crucial gaskets like that (really any gasket at this point) I only go legit OEM mazda. Its never worth gambling on saving $8 or whatever the difference is if I have to end up doing the job twice.

These half moon pan gaskets are a bit of a mine field.
There are 2 variants of these gaskets: with a cut-out for the MBSP and without the cut out.
The official Mazda part numbers are these:
Half moon front (01-05 MBSP): B541-10-427
Half moon rear (01-05 MBSP): B541-10-428
Half moon front (94-00 w/o MBSP): B6F4-10-427
Half moon rear (94-00 w/o MBSP): B6F4-10-428

The ones with the cut outs are often said to be compatible with a 94-00 motor, but I think you need a bunch of RTV on the corners to make them seal correctly.
If you google the part number you can see the difference. If you want to play safe I would order them directly from Mazda. If you go aftermarket make sure to double check the style of the gasket.

I have a feeling that my oil "leak" may have been from excessive crankcase pressure pushing oil out the oil pan gasket or front main seal. Granted it's just been idling, but after making adjustments to my catch can setup and enlarging my PCV ports, I haven't noticed much oil coming out the front. I'll blast things off with a can of brake cleaner and see what happens.