In November 2006, I replaced our '94 FD's Fuel Pulsation Dampener. Unfortunately, during that job I broke the rear OMP line (see far left picture below). I repaired it using 1/8" ID, 1/8" wall thickness Viton tubing from McMaster-Carr (see center and right pics). No problems for one year and 3100 miles. However, last week, I noticed oil smoke sneaking up between the rear of the engine and the firewall. Apparently oil is coming from somewhere and dripping on something hot (haven't looked yet).

This engine has always leaked some oil, not much, but enough to justify kitty litter on the garage floor. The dipstick still reads full, since I topped it up about 200 miles ago. I'm going to try and locate any new leak, but would appreciate any comments you might have as to whether my repair might last a year and 3100 miles and then leak, or if you think it might be coming from the turbo oil lines, etc.

I REALLY don't want to tear the engine down unless I have to, but I can't see any way to check my repair without doing that. Any ideas? Thanks!

 

Considering the location, you should be able to get a bright light in there and take a peek with the UIM off. It should be pretty obvious if you have any oil dripping or pooling under the rack.

 

While you are back in there, replace your lower intake manifold paper gasket with an upgraded oem metal one.

later

 

+1 ^ mine blew because the OMP or something leaked a lil oil in there and the paper gasket just wasnt able to hold up anymore... gave signs of a blown motor

 

Thanks for your replies. I went under the car today and removed the transmission undershield, which was soaked with oil on both top and bottom. The oil had also blown back onto the DP/cat converter mounting flange, onto the cat converter heat shield, and onto the air injection pipe. Forward of that, the engine crossmember at the rear of the engine and its motor mounts were very wet.

The pan was dry, and pan flanges were dry except for the far rear row of pan bolts. The highest point on the engine on which I could find oil was the lower portion of the rear turbo's compressor housing. It almost looked as though the gasket at the rear turbo air outlet port might have been leaking, but I thought there would be only an air leak there. I did check the torque on the two #10 bolts holding that pipe on, and they were at about 82 in-lbs. I had replaced that gasket back in 2003, when I did the vac hose job.

I couldn't find any indication of oil coming from up high on the engine; I could see the FPR from below, and it was dry. But it's really hard to see. Don't want to pull the UIM unless it's absolutely necessary.

The top of the clutch housing and the rear of the engine itself seem to be dry. I have no way of changing the LIM gasket... I didn't even know oil could leak out of there. Can't see it, anyway. Any chance this could be a rear shaft seal leak? Could it somehow throw oil onto the rear turbo housing? Could it be the turbo itself leaking? If so, what is the path? The oil lines are dry, and I see no gasket leaks at their interfaces (the ones I can see).

The engine is stock except for a Bonez S/S downpipe and Viton vacuum hoses. It is the original 1994 engine with 93+K miles on it. I'm pretty much convinced I have to take it to Irvine Mazda and turn Ron loose. I don't know what to tell him to do, though. Replace rear output shaft seal? He can do that by dropping the transmission and doesn't have to pull the engine.

 

Can anyone verify that the LIM gasket is a possible source of an oil leak? The engine runs perfectly, and the LIM gasket was changed by a dealer to a new part number, to end a persistent EGR problem, back when it was under warranty in 1995. Do they leak after long duty?

 

There's really no oil in that location for the LIM gasket to leak.

 

I think I may have a similar oil spray pattern as you with the exception that my subframe all around the pan appears to be wet from oil. My oil pan was resealed 1.5 years ago.

I don't think that kind of spray patter could be caused just by your turbo leaking unless you have a serious leak there. I just don't see how it could push out that much oil to soak things the way you described. Perhaps it is a rear shaft seal perhaps combined with something else... I'm far from an expert on this.

 

why dont you clean off all the oil with engine degreaser and start it up and see if you can find the leak then.just a thought

 

That's what I thought. Between the FWM and the parts catalog illustrations, I think I've identified all the oil connections. But unfortunately I can't see the upper part of the block and turbo on the passenger side... just too many pipes & tubes. And I think that might be where the leak is originating. Good idea, if I could see better. I have cleaned the cat converter shield and the other under chassis parts that were oil-soaked, but I already know they are not the source... there are no oil tracks down the side or rear of the engine that I can see. Would a rear shaft seal leak be able to coat the bottom of the rear turbo compressor housing with oil? Seems unlikely to me. And the lower stuff on that side of the engine is dry.

 

Just had the engine front and rear shaft seals and O-ring, oil pan gasket, oil level sensor O-ring, and oil pan (not sure why that) replaced, and while that was done, a new OEM clutch installed. Labor = $1300, parts = $501, altogether including tax $1840. This is the first time for all this stuff in 14 years, and apparently my OMP line repair is NOT leaking. Whew! Just thought I would close this thread out with results. (Wifey is happy there's no oil on the garage floor anymore.)