Rear Crank Seal Question

[Rush]

Hey guys! So the L16 I built for my car has developed a fairly 'eager' oil leak. I cleaned everything up under the engine to try to find the source of the leak and the only spot I see a small drip is on the bottom of the lip of the bell housing so it seems to be between the tranny bell housing and the engine. Most likely the rear crank seal, but I'm just guessing.

I bought a new seal (OEM this time), so a couple questions; am I better off pulling the engine or dropping the tranny? I haven't got a lift, just ramps and jackstands. Also, please toss up any tips for this job you feel would be helpful as I've never replaced a crankseal without the engine being on a stand. And, if you know if there's a more likely culpirit for the leak, please let me know.

[BEO 510]

Transmission or engine oil? You can smell the difference.
Another option is you was unlucky with the rtv and side seals at the main cap?
Then why do a new seal failure, groove in the crank?

[Rush]

It's definitely engine oil. I'm guessing either the seal itself was subpar (it was a Felpro kit) or more likely, I simply didn't install it perfectly. I may have pushed it back a little too far or something like that. I don't know if there's a groove in the crank, but I didn't notice anything when assembling, however, that was 10 years ago so details are a little fuzzy in my head.

[510rob]

It would probably be less work to {get the driveshaft out, get the trans out, get the clutch off, get the flywheel off} to have a look at the rear main seal before you try to pull the motor out.

[BEO 510]

Agree with 510rob.
The reason i mention the side seals and rtv, i know a guy who replaced a "new seal" but was still leaking.
At the end the rear main cap was pulled and side seals done again, leak stopped.

[Rush]

Thanks, guys! Beo, I'll definitely check that. Thanks for the tip!

There's kinda one last 'show' I want to take my car to on the 21st. After that I might start on the leak problem. Really not looking forward to it.

[510rob]

While you have the motor out, start measuring the engine bay for triplechargers and nitro nozzles and whatnot :O

[Rush]

Lol! Yes! Me

[510rob]

ha ha ha!

[Rush]

Well, I finally started on this dreaded project yesterday. Dropping the tranny is such a nightmare alone & this is my 2nd time doing it. Yuck. I just got it out yesterday & today I'll take the clutch & flywheel off and have a look at the leak situation. I really hope I can repair it in place without removing the engine, too!

Still open to any tips you might have!

[datzenmike]

Can't see the engine plate. Is it there?

No one has mentioned a bad oil pan gasket.

[Rush]

Is the engine plate the 2 sheetmetal-like dividers between the engine & tranny? Those are there.
About the pan gasket, I couldn't really tell if it's the problem but I bought those steel L shaped pieces that are supposed to support any waviness in the pan caused by the bolts so I'm going to install those while I'm under there.

I was able to get the seal out fairly easily, thank god. The seal spring was out of place, just hanging around the crank. I don't know if I knocked it out with the screws I used to remove the seal or if it was just out of whack to begin with. I cleaned up the crank and the block/cap with a little lacquer thinner and made sure there are no burrs or anything to damage the seal so I think I'm ready to slither back under there & install the new seal. I'll put a little grease on the inner surface & try to get the seal on squarely and flush to the cap/block. There don't seem to be any grooves on the crank. Fingers crossed!

Here are a few pics from today:
Before cleaning


After cleaning

[datzenmike]

They are L shaped and Nissan only put them on one corner at the back. I had an extra. You have to trim one as they overlap.

If there are a lot of miles on the pilot bushing and the release bearing, now's the time to replace them.

[Rush]

Ah! Ok. I actually bought a set of those but I didn't know what they were called. Pilot & release are new, thankfully.

Progress report: Seal, flywheel, clutch, slave, and tranny are all back in, and oil pan L dealies are installed. I just need to put the driveshaft back in, and fill the transmission & I'll be finished! Yay! I rewarded myself with a new patch I made for my shop romper! I think I've earned it.

[Rush]

Good news to finish this out: No more leaks! We had an unseasonably warm day here on the frozen tundra (50º!) so I started the Datsun, pulled it out of the garage & took a few runs down the driveway and back. Not a drop leaked! I'm so glad!

Also, while I was taking the car apart for the repair, I found out that the mystery vibration I had right before I put the car away for the season was probably caused by the TWO missing driveshaft bolts! Not only that, the remaining 2 were fingertight! THAT could have really been a bummer! I bought new bolts, lock washers, and nylocks! They should stay put now. I also adjusted my clutch slave & that feels great, too.

Even though this job is awful, especially by yourself, problem solved so, YAY!