I have an oil leak on my '76 that seems to not follow usual patterns. The leak only occurrs when the car is warming up. It doesn't leak when it's just sitting and it doesn't leak near as bad (almost not at all) once the car warms up. It drips off the oil filter, but I can see the oil dripping from the oil cooler above, onto the filter. At it's worst, it drips about a drop a second. I suspect the oil cooler seals, but, wouldn't that leak all the time, not just at warm-up? And it certainly seems like the drip wouldn't slow down when the car is warmed up if it was the cooler seals. I also kept an eye on the oil pressure sensor and didn't see any oil leaking in that area.
Thanks in advance for your thoughts,
Tom

I'm troubleshooting an oil leak myself and had a drip from the same general area. I had drip problems at all times though, so it may be different. I'll tell you about my findings, which may or may not be helpful to you.

So as in your case, the oil was coming from above. I first checked the oil pressure sender as it is easily fixed and a likely cause. It seemed okay, it wasn't leaking from the top, as apparently is common. So I figuered it must be the oil cooler. Not wanting to drop the engine, I did the seal replacement job. My seals were old and were a little cracked, but after putting in the new seals, the problem was still there. By the way, the oil cooler seal replacement job is not fun... Its right up there with putting the resevoir tubes into a new master cylinder.

A few weeks ago I enlisted the help of a couple friends to help drop the engine. After dropping the engine and removing all the tin, manifold, throttle body, etc. etc. I noticed that the pressure sender had some kind of plastic wrapped around it, and that this plastic went beneath the cooler and seemed to be very hard. I think what happened is the guy who installed the sender didn't realize that part of the packaging was still on the sender... Either way, it looks as though thats where the leak was coming from. I'm taking my oil cooler out to be tested tomorrow, so thats the deciding factor.

My reccomendation is check out the pressure sender, by taking it off and putting it back on, or even replacing it (it's cheap) and then do the seal replacement as per the pelican article, and if that fails, drop the engine and check the cooler. Beyond that I understand there are a couple other things that can go wrong up there, but those are the major ones.

-Tony

This item from the Eastwood Company http://www.eastwoodcompany.com may be helpful. (The "fluorescence-enhancing glasses" could be cool too).

Alfred

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I know one thing that helps is to get some spray brake cleaner and really clean off everything in the area and then get under the car as you are warming it up and see if you can spot where the leak is comming from.

And from my experience I would rather drop the engine to rr the oil cooler seals than try and do it below the car...plus then you can have the cooler tested...I have had one blow on me and it is not a fun mess to clean up...

good luck...

oh one last place to look is the seal around the dizzy shaft, if it is not up to snuff I have seen some oil come from there, but usually not very much...

Tony

I was looking in the 914 tech manual, and on page 210 of the engine section it describes what I believe is my problem. It says, "If the pressure relief valve is stuck in the upper end of it's cylinder, cold, thick oil may cause a leak in the oil cooler."
That would explain why my car doesn't leak when it is just sitting and also doesn't leak when it is warmed up. Anyone know anything about the "oil pressure relief valve" and how to check/repair them?

See the big slot-head screw thing on the lower front corner of the engine case? That's the cover for the oil pressure relief piston and spring. Remove that and take the piston out. Check the bore as carefully as you can, check the piston, and make sure everything moves smoothly.

--DD

pressure sensor and cooler seal leaks appear at the back of the cooler, obviously where the seals are. If oil is dripping from the coolers center, front or far right then the cooler itself is probably leaking.

No leaking when stoped - no pressure.
slower after it warms up could be from heat expansion making a crack in the cooler tighter. Maybe ?

Mike D.

Warmer oil is thinner and gives you lower pressure, as well. Could be that the leak is only under lots of pressure.

--DD

Well, I dropped the engine, replaced the oil cooler seals, and the oil pressure switch. (Also, while I had the engine out I cleaned and/or painted everything I could, adjusted valves, changed shift bushings, replaced the impeller, etc., etc.). Then engine went back in friday night - Thanks to the BS Chairman, and Hawk. I got everything connected back to it today, crossed my fingers and started it up. I let it run for about 15 minutes, and no oil leak. WHEW!! Thanks, everyone for your advise
Tom