Having read quite a few threads on "oil leak" I didn't come across anything that looks like the one on my wife's '94 PEP. 82001 miles, stock except for Bonez DP. The first pic is looking up toward the bottom of the oil filter mounting pedestal. Note that the iron block surface to the rear of the 2nd rotor housing is oil-saturated. The second pic is looking down (obviously) on the filter; again note the oil on the engine side of the pedestal. I'm quite sure the filter O-ring is NOT leaking (see how clean the bottom is in the first pic). So that leaves the interface between the mounting pedestal and the boss on the block, maybe the oil pressure sensor, or something else in that area. The car does not leak when sitting in the garage, only after running, so I think it's in the high-pressure area of the oil path. But I would like to request opinions from this august group. Has anyone had leakage problems with the filter pedestal/block interface? Is there a gasket between the flanges or just sealant? Thanks for your time!

---- Bill

 

There are two rubber o-rings between the iron block and the aluminum oil filter pedastal. Replace them and el leako will be el fixo They are a known problem area.

 

Thank you, DamonB! I appreciate your response. Will get on it right away.

---- Bill

 

Found the 2 O-ring's mounting locations in my 1994 RX-7 factory manual. I'd like to replace these with Viton O-rings, but don't know their dimensions. I could order new ones through Mazda (looks like I have to order that triangular gasket for the air tube anyway), but would prefer just to have the dimensions without having to remove the oil filter pedestal first, which downs the car until I get replacement parts.

Any help here? Thanks!

---- Bill

 

Honestly the stock ones are going to last another 10 years before they leak again. I wouldn't bother.

 

DamonB,

OK, thanks; I'll consider and maybe do that. I came up with these P/Ns for the replacement:

O-Rings for pedestal: 99541-01601
Large "O" ring for triangular seal at air tube/throttle body interface: N390-13-W69
Washers for high-pressure banjo connection to pedestal: 99562-1800

Is this replacement possible without any more purchased parts? And can this be done without removing the oil pressure sensor for wrench clearance, or do I have to take that off too?

Thanks!

---- Bill

 

I'd also do another test as well. Get a can of brake cleaner, and hose all the oil off with the brake cleaner so it's somewhat clean down there. Start the car and run it at idle - watch for leaks. Rev the engine up a little as well - that increases the oil pressure.

I had a VERY similar leak this week - turned out the rubber gasket on the crappy Fram oil filter that came with the car was bad, and was leaking BIG TIME. Saw it clear as day when I revved up the car. New oil filter, problem solved.

But, yeah, it's definitely either the oil filter or the 2 oil filter pedastal o-rings.

Dale

 

dcfc3s,

Thanks for your input. Any comment on my last questions?

---- Bill

 

Update... the leak was definitely the two O-rings under the oil filter pedestal. After I removed the pedestal it was obvious: the entire flange area outside the O-rings was wet with oil. The O-rings were permanently flattened into "washers," and were not very flexible. I did have to remove the oil pressure sensor to get wrench clearance to the rear pedestal mounting nut. Replaced the O-rings, remounted the pedestal and the OP sensor. Now waiting on the banjo union washers and the air tube O-ring; that O-ring was $19.88! (I did use OEM O-rings rather than order Viton replacements.)

Noted that the lowest throttle butterfly is dirty after 82K miles. Upper ones are clean. Will probably use paint thinner to clean off the butterfly and slightly into the throttle bore. If anyone has suggestions on the best way to do this, please let me know!

---- Bill

 

Everything is back together. While the air tube was off, I cleaned the throttle butterflies and throats with a rag dipped in paint thinner. Lots of black gunk in there. For maybe that reason (?), there is no longer a miss going up through 3000 rpm, which has been there since about 20K miles on the car. Idle at first run (after warmup) was quite high; I reduced idle speed to about 800 rpm with "TEN" jumpered to "GND" in the Diagnostic Connector, a la Miata standard idle adjustment. Seems to have fixed the high idle. There are still a few drops of oil on the garage floor. (I'm hoping that is just residual from pooling in the chassis various places.)

---- Bill

 

Wow. I had the same issue. Good thing you brought this up before me. If you find out anything else. post it up. thanks.

 

good thread! i think i may have the same issue as well. i've had oil leaks for the past year, and i've resealed my oil pan 4 times! but it's still leaking...i thought i did a near perfect job in resealing the oil pan this time so i didn't understand why it was still leaking...but i noticed that picture by the oil filter where the oil is looks very similar to mine...thanks for posting all the part #'s for the o-rings.

 

Wow, I think that if I had to reseal the oil pan four times (and with the motor in the car no less) without fixing the problem I would have put my head in the oven by now

Way to hang in there

Also, any more pics of your car, and where in NJ do you live?

 

Hahaha...true...but i'm quite good at removing the oil pan now...and it's actually fairly easy now after having done it so many times.

i'm in central jersey by Rutgers University. There shoud be another pic of my car in the "post money shots or you car" thread under the 'Interior & Exterior' forum.