I have been hunting down an oil leak originally I thought it was my OMP lines. Thought hey maybe they are broken? Maybe they were maybe they were not? They were broken by the time I started removing them lol. SS lines are installed now. Anyways still seems to be leaking a bit of oil maybe fuel maybe a little bit of both?! I started my car today and got under it and watched and saw liquid coming out from the bottom of the rear LIM runner closest to the trans. To me it looked like oil. So I keep letting the car run wait tell its warm still leaking a little bit. But I notice now my trans is leaking black fluid out of the trans service plate. So I think hmm probs rear main + LIM? But then I notice that I have a nice line of blackish fluid running down between the trans and the irons. As well as on the trans case its self next to the Iron has some fluid running down. I don't smell gas so I don't think its fuel? I noticed trans has a cover plate around the motor so I thoughts well maybe my LIM is leaking and its just leaking **** into the trans thought the plate and out the bottom. I notices that whatever was on the trans seems to have evaporated making me think fuel. Any Ideas? New o-rings and insulators as well as dampener was installed when I put in the new OMP lines It was leaking oil before though. Car runs and drives fine just leaks a good amount.

 

Here Is an image the mix part is just my assumption it may very well just be oil just burning away. Leak section I saw fluid come out of where I circled.

 

The LIM can leak, a smoke test up the exhaust or down the inlet would be definitive, as fluid leaks are notorious for being difficult to pinpoint.

Assuming it's just sitting idling, wouldn't expect a leak there, but the secondary runner walls are soaking wet in use when the injectors come in. The metal gaskets if reused a few times dry, will let fuel run down the block when they die however, I understand the early cars even had paper gaskets, but can't imagine any old ones in the wild still!

 

I think when LIM gaskets let go, you get a small vacuum leak that ruins the cars ability to smoothly idle.
If your idle is okay, I would check the secondary turbo oil drain line. Where the drain pipe meets the block in that area, there's a small gasket that is common to leak.
Although that pipe is not pressurized, usually just makes a mess on the oil pan and motor mount, oil can climb up slowly on dirty surfaces.

 

Idle is fine with my PFC. Originally I thought maybe my drain was bad but as you can see in the pics I have leaks coming from above that drain.

 

I'm thinking it's not from the LIM but a rear main seal leak. A leaky rear main seal will fling oil around the bell housing and with the metal cover there it's getting around that cover and leaking.

Don't know if you can remove that cover and have a look.

Dale

 

Wow, that's only accomplished on a well sorted setup.

Rear main seal may be your culprit. Does the clutch ever stink or slip after hard driving?
You can try removing the clutch inspection plate to check the inside of the bell housing for a oily mess. Use a clean finger or towel.

 

Also the OMP goes straight into the rotor housing, it's nowhere near where it could come back out of the intake port.

Dale

 

In the instance of a failed seal between the manifold and the block here, idle was unaffected...or so insignificant, the difference couldn't be heard, only give-away, the leak through a gap of a few thou.

 

Thanks I set the PFC myself tuned it as well. I have only had the car for a few months 1st rotory. Bought it thinking it was a well sorted car online only to get a leaking mess of oil. Live and learn I guess. Good thing I have been building cars for last 12 years. No clutch mess but there has always been oil in the bell housing. I think your right and it's the rear main or the o-ring on the rear gear.

 

I was unable to remove the cover to many things in the way. But I think your right on the money replacing rear main is more easy then then LIM and it's a JDM 92 FD and has a metal LIM gasket from what I can see so im sure it's been replaced. I did start the car back up after cleaning the oil and noticed that the oil seems to come closest to the edge trans side so makes the most sense it would be flung out and onto the side like you were saying. I will give the rear main a shot and see what happens.

 

If you remove the inspection panel at the bottom of the transmission you should also be able to look up in there with a good flashlight and see if there's a spray of oil between the flywheel and engine.

Dale

 

Yeah seems like a rear main or a bad oring. Waiting on a 54mm to come in the mail. Also seems like my motor may gave been rebuild im assuming that normally oem motors don't have numbers on the case bolts?

 

Yeah the factory didn't number the bolts. Of course at this point it's not common to find a car on the original motor anyhow.

Make sure to get the Mazda orange rear main seal. Atkins sells a brown one that's for the RX-8 - they don't fit right and WILL leak.

While you're waiting I'd get some brake clean and go to town cleaning up as much of that oil mess as possible. That will make it a lot easier to verify you fixed it and also make it possible to track down future leaks.

Dale