I have an oversized stud kit on my Cosmo motor, and I'm leaking oil from the bellhousing. I thought it might be a bad input shaft seal on the tranny, so I pulled it. The tranny seal looks fine . That means the oil must be coming from either a) one or more of the studs or b) the rear main seal.

I followed the instructions when installing the studs, with correct O-ring placement, and generous use of Hylomar.

My rear seal was included in a new RX-8 stationary gear, and I used Hylomar between it and the rear iron, as instructed by Mazdatrix.

It's hard to tell exactly where the leak is coming from, since everything back there is coated with oil.

1. Any ideas on how to locate the leak?

2. Silicone instead of Hylomar?

3. Anybody else experience this problem?

 

The studs would not leak oil but coolant mainly. Your leak is most probably from the gear. Since you're not using the o-ring due to the rx-8 gear you should have used some sought of sealant other than hylomar.

 

Thanks. Any concerns with pulling the gear while the engine is still put together? I figure I'll remove the gear, clean off the Hylomar, put on some silicone sealant, and stick it back in there.

 

You could probably pull the gear with the engine in the car... but DO NOT turn the eccentric shaft once you get the gear out!!!

 

You can pull the gear in the car, put some sealant around the base of the gear, and set it back in.

 

Yeah, you can pull it while it's still in the car. Just be careful sliding it back in.

 

Thanks everybody. The next trick will be figuring out how to turn that e-shaft nut while the engine is installed. I have one of those long wrenches that I won't be able to swing under the car. I went shopping for impact wrenches today. Has anybody been successful with a 300 ft-lb electric one? I don't have an air compressor, and don't want to start a new tool collection.

 

I've broke a few flywheel nuts loose without air.

On your rear iron, you've got your transmission mounting holes. Grab a small chain, anchor that chain down to the top passenger side hole in your rear plate. The stock transmission bolt will work. Anchor the other side of the chain down to one of your clutch mounting holes on your flywheel. That will keep the engine from turning while you're giving that flywheel nut hell.

Get yourself a good double bicep pump, then rip that nut off. That usually works best for me.

I've got the flywheel socket and breaker bar if you need to borrow it.

 

Yes, the following two will do the job:
Hitachi HW22
DeWALT DW294

Long time ago, I had to rent the Hitachi HW292 and was blown away with its performance, so I decided to buy one. That's when I found the Dewalt!!

When it comes to the flywheel nut or eshaft bolt, I don't even sweat it Both will come out in a matter of miliseconds

 

Some of the advice scares the hell out of me...
I've seen rear irons crack cause of stupid stuff like this, and a good sized impact gun will EASILY take the flywheel nut off.
Why get complicated?
My Craftsman Pro *electric* impact gun always takes it off; if not immediately, hit it with a torch to burn the threadlocker off, and 260 lb-ft always works.

There is only one tension bolt (well, stud in your case) that has oil in it - the left / upper most corner, so I doubt that's the case.

You SHOULD have been able to tell if it's ENGINE oil or TRANSMISSION oil that's leaking - that's #1.
You should be able to tell just from the smell.

Transmission oil would automatically be input shaft seal.

Engine oil will most likely be:
1) o-ring on rear stat gear, or
2) rear main engine oil seal

What's the difference?
Where the oil leak is coming out from...
Oil leaking from BETWEEN rear iron and rear stat gear is o-ring.
Oil leaking all over rear stat gear is from rear main oil seal.


-Ted

 

http://www.mazdatrix.com/getprice.asp?partnum=49-220TB

use that and a long breaker bar. Easy as pie.

 

Speaking of scary advice...

None of the tension bolts or studs have oil running through them. The upper left tension bolt you describe does not run through the upper dowels; that would block off the main oil passage to feed the front irons. In order for oil to leak out of the stud or tension bolt closest to the upper dowel, you would have to have a serious gouge in the iron or rotor and/or a faulty dowel o-ring, which would more than likely cause an external leak at the rotor housing to iron junction, or allow oil to mix with the coolant.

The only tension bolts exposed to oil are the two lowest ones, which should be under no oil pressure.

 

hylomar is great for holding gaskets in place but it does not seal worth a damn IMO.
Right Stuff sealant is the best that i have found and it is not cheap.

 

Did you put some kind of sealant between the bottom of the housing ears and irons? This could be your leak too.

 

Yes, I did seal that area, thanks.

 

Now that I pulled the rear stat gear, I share your opinion. Not only could I see the traces where the oil had blown through the hylomar, but the hylomar had oozed all over the place -- it was even on the inner face of the stat gear, near the rotor. And before you think that I used too much -- I didn't. Only a thin coating in the recommended area aft of the oil supply orifice. This stuff definitely isn't good for high pressure sealing.

I removed, cleaned, and re-sealed with a thin bead of silicone. I was lucky enough to have some of the Hylomar solvent from my last rebuild, so this was fairly easy. Also, I was able to use a piece of pipe on my breaker bar to get the nut off. Wish me luck. Thanks again for all the advice.

 

Good luck, that should work.