987 S big, pass side oil leak...

[masraum]

I have a leak on the passenger's side, and this one is big. Lately, when I'd stop the car at work or home after my commute (84 miles @80mph), I'd notice a whiff of hot oil smell, but I wasn't seeing any drips, drops, leaks, etc... Until... last Thu I stopped for gas when I was almost home and noticed a little smoke coming out of the rear pass side wheel well. I filled up and got home. Now I've got the car up on stands. The bottom passenger's side of the car is covered in oil. It's not on the oil filter housing or drain plug because all of that stuff is dry.

I don't see anything obvious from under the car. I assume I'm going to have to pull the two access panels to see the front and top of the motor.

I don't believe I've been smoking or burning oil, and I think that's the common symptom of AOS issues.

I found a thread online where a guy had a leak on the passenger's side, and it ended up being the plastic oil file pipe was cracked. My car is 17 years old, so I can see how any plastic pipes would no be brittle and prone to cracking.

This is a PITA!

The oil fill pipe does look like it would be a "good" source of oil on the passenger's rear end of the motor if it was leaking.



The green box area is essentially dry. The orange oval above it is wet, but not that wet. The red oval and square on the right are very wet, and then anything behind those areas on that side are also wet.

[DWBOX2000]

Just a guess, maybe something as easy as spark plug tube? Good luck.

[stevej37]

Did that engine have any of the head stud problems like the air cooled 911's?

Just asking because I remember finding the pool of oil under the engine of my SC on one side.
I had all the studs replaced and no leaks after.

[JackDidley]

Look at the oil air separator and its piping.. Pretty common problem.

[masraum]

Originally Posted by JackDidley

Look at the oil air separator and its piping.. Pretty common problem.

I'm just not sure, the big hose that runs from the oil fill port in the trunk is very wet and is essentially above all of the AOS stuff. So from a certain point of view, how would oil from the AOS get up to that hose. But, the stuff under the AOS is wet, and even the stuff to the outside of it (towards the outside body panel) looks pretty wet. It doesn't seem like oil from the fill tube is likely to end up over there.







Regardless, working down through the hole between the back of the top and the upturned body panel that goes up when the top goes up seems like it's going to be a huge PITA!

[JackDidley]

I think you will have to dig into it. Maybe clean it off and start there. The AOS problem is pretty common, thats why I posted. Oil vapors can go up though. I was lucky, my 08 Cayman never had the AOS problem. Sold it at 98k miles.

[masraum]

Originally Posted by DWBOX2000

Just a guess, maybe something as easy as spark plug tube? Good luck.

I don't think my car has those. I think they were specific to 2002 and earlier.

[Jeff Alton]

Correct, you do not have spark plug tubes on your motor.

Cheers

[David]

Transmission cooler or CV joint?

[masraum]

Originally Posted by David

Transmission cooler or CV joint?

I've seen leaking CV joints before on other cars, and it's usually just grease in a circulate spray pattern around a split boot. I assume this should be the same. This definitely seems like an oil leak. I suppose it could be transmission, but I would think that would be thicker, and this seems more like the viscosity of oil and doesn't smell like gear oil.

[onewhippedpuppy]

Very fuzzy but I seem to recall that corrugated hose just under the oil filler pipe is a breather, and I had one crack on a past Boxster or Cayman. That would explain the film on everything but not a large oil leak. I also can’t see where a cracked filler tube would lead to an oil puddle sized leak. I know the AOS is common but I don’t recall it typically being an external leak? Have you closely inspected the hoses that go forward to the front oil cooler?

[DWBOX2000]

Is that large hose the coolant and the pipe below the plastic fill corrugated pipe? It’s weird because from the picture, it looks like the oil came downward since the AOS looks relatively dry. The weird thing is there is nothing above it so my guess is the plastic fill pipe cracked up high or if possible, disconnected. I’ll be curious to the answer. Best of luck.

[masraum]

Originally Posted by onewhippedpuppy

Very fuzzy but I seem to recall that corrugated hose just under the oil filler pipe is a breather, and I had one crack on a past Boxster or Cayman. That would explain the film on everything but not a large oil leak. I also can’t see where a cracked filler tube would lead to an oil puddle sized leak. I know the AOS is common but I don’t recall it typically being an external leak? Have you closely inspected the hoses that go forward to the front oil cooler?

I'm not sure how oil would get to that tube either, but I assume stuff gets around when the engine is busy.

Yes, I have read that the corrugated pipes that go to the AOS get brittle and crack. I'm just not familiar enough with the AOS system to know how much oil it would move around. I think there are 2 of those corrugated pipes for the AOS, and they run about $100 each. I'm considering replacing those 2 pipes and since I'm at it, the AOS. I'd hate to replace the pipes, and then have the AOS go within a year. But, spending $350 on "it could be that" and then not fixing the leak would suck.

[masraum]

Originally Posted by DWBOX2000

Is that large hose the coolant and the pipe below the plastic fill corrugated pipe? It’s weird because from the picture, it looks like the oil came downward since the AOS looks relatively dry. The weird thing is there is nothing above it so my guess is the plastic fill pipe cracked up high or if possible, disconnected. I’ll be curious to the answer. Best of luck.

The large hose that's central in this photo is actually the oil fill hose. It looks like a radiator hose but it's much, much thinner and softer.




I think the corrugated lines are for the AOS.
One is down low/below the AOS with the purple arrow in the photo below.

[masraum]

The three hoses in this screenshot go to the AOS. Two are hard corrugated plastic. I think the short elbow is more like a little heater hose.

[speeder]

I don't know those cars well enough to offer help other than to say that the AOS would be on the RH rear part of the motor on a mid-engine car because it was on the LH front on my 996. Looks like you're ahead of me there, examining the plumbing going to it.

[onewhippedpuppy]

After your last picture I definitely remember replacing one of those corrugated pipes with the SOB squeeze fittings. I ended up butchering it because it wouldn’t come off correctly.

[DWBOX2000]

Thanks Steve. I learn something new everyday.

[masraum]

I went out today, and warmed up the car (sitting idling) and ran it and revved it a bit. There's no new oil from idling and revving. I guess I'm going to top the oil off and drive it a bit to see if I can see anything.

If I remove the oil cap while the car is running, there's what seems like very little suction. There is some, but not much. The car seems to idle and run OK.

I do hear a funny noise when I rev it that sounds like something small and loose bouncing around inside the piping from the air filter or something like that.

Without a reasonable diagnosis, and needing to use it to commute to work, I'm approaching the point where I'll get it back together, test it thoroughly and then run it into town to a mechanic. Crap!

[onewhippedpuppy]

Worth noting, I can’t recall ever seeing a Boxster or Cayman that didn’t have at least a light oil film in the area that you pictured. Never had one that used or leaked a measurable amount of oil, I always assumed they tended to get dirty due to mid-engined airflow or lack thereof.