Help - Oil leak on top of engine - newbie - 986 Forum - The Community for Porsche Boxster & Cayman Owners

chitowndad · 08-01-2007, 07:15 PM

Hi, I'm a newbie on this board so if I'm posting in the wrong area, I'm sorry. I have a 2001 Boxster S with 8,000 miles and today when I was replacing the air filter with a K&N filter I noticed a very small leak on the top of the engine. I'm attaching a picture of it. I would appreciate any help!

Thanks,
-Steve

wvicary · 08-02-2007, 04:12 PM

Sorry hard to tell from your pics but I think it's from the oil separator.... can you resize the photos?

CJ_Boxster · 08-02-2007, 04:43 PM

I can tell where that picture of the engine is, That oil is right under the AOS oil lines and under the Engine Oil filler Flex Tube.

Looks like i see some oil stuck on the Engine Oil filler tube... Could either be that OR the AOS is leaking oil on top of the Engine Oil filler tube, then it drips down to the engine crevas which means your AOS (Air Oil Separator) is bad. Tell me, Has the car ever smoked for about 20 seconds once or twice during start up since your ownership... if so... AOS is ready to be replaced.

chitowndad · 08-02-2007, 04:45 PM

I have a better picture but it's 600K, which is too large to upload. Can I email it to you? The leak is on the top of the engine near where the engine and the transmission connect so my first thought was that its the rear main seal; however, I have no leakage on the bottom, so I'm confused. It's on the right hand side of the engine block near the rear of the engine block.

Can you describe how to identify a RMS leak? That might help...

Thanks,
-Steve

chitowndad · 08-02-2007, 04:56 PM

I forgot to add that yes, it does smoke on start-up. Scared the crap out of me when I saw it the first time! The car only has 8K miles! I thought is was my 80's Camaro at first (bad valve guides)... So can you replace the AOS yourself?

Thanks,
-Steve

CJ_Boxster · 08-02-2007, 05:11 PM

Whoa, only 8k miles on the car and its a 2001... Well thats typical of a bad AOS. The AOS is basically a One way check valve from the crankcase to the intake manifold... Also it keeps the oil from foaming.

When they go bad, they allow oil to come up into the intake and down into the cyclindars where the oil gets burned, its only when you start the car up after its sat for some hrs that enough oil can sometimes find its way into the engine and smoke for afew seconds during startup.

RMS leaks are simple to find.. if you have no oil anywhere but under the tranny and rear bottom area of the engine block... usually an RMS leak.... thats if your valve covers arent leaking or your AOS or the oil filler tube.

chitowndad · 08-02-2007, 05:20 PM

Thanks, I'll trace the hose and see what else I can find. I'll call Porsche to see how much an AOS costs, etc. I'm pretty handy (restored a 1991 300ZX before buying the Boxster) so I'll try doing it myself first.

I bought the car this past May with only 7,600 miles and it's a 2001 S that's Black and in cherry condition! I paid $28,000, which I thought was a very good price for a flawless car from a neighbor that I play cards with. He was the first owner and only drove it on the weekends between business trips. I'm finding myself doing the same thing, using it to go for the weekend drives only...

I almost bought a 1999 911 with 34K miles for $32,000 but that one got away from me... I wasn't fast enough.

chitowndad · 08-03-2007, 06:24 PM

I figured this one out. There is a tube that runs along side and under the Air Oil Separator hose and it's shaped like a stretched "S". It also looks like an accordion on one of the ends. There's a clamp that appears to be not that tight. The clamp looks goofy and I'm not sure how to tighten it. It looks like I need a special tool (like a crimp tool) to remove or tighten it.

See the attached picture. The screw driver points to the clamp...

I'm still thinking of replacing the Air Oil Separator as well. I found it on an auto discount part store online for $100. Is this part difficult to replace?

How do you disconnect the hoses on the Air Oil Separator?

Thanks,
-Steve

CJ_Boxster · 08-04-2007, 01:40 AM

Well that clamp doesnt get any tighter than it can squeeze on its own, its a normal clamp that you remove with simple pliers. you probably cannot see the other end of the clamp that you'd grab with the pliers cause the AOS lines are blocking your sight. You can get the AOS cheaper from suncoastporsche.com

I sent you a PM about how to remove the AOS lines.

If the Oil Filler tube is the cause of the leak, the best way to seal that leak is to remove that portion and line the interior of the tube with silicone to create a seal between it and the hose it connects to, then place the clamp back on... Dont start the engine till it drys so that it can cure and you dont suck a hole though the seal because of the crankcase vacum.

Rodger · 08-04-2007, 10:27 AM

See how to replace/reseal the oil filler pipe here:

Oil Seperator and Oil Filler Pipe Replacement

FWIW, I'm nearly certain you don't have an AOS problem. It's totally normal for a Boxster to puff a little smoke on initial startup. Since your's does it very infrequently, it's normal and nothing to worry about. If you had a bad AOS, your car would puke a large volume of smoke, and continue doing it for > 10 seconds at startup.

As for the oil filler pipe, you may find that it has been sealed with a piece of worthless fabric tape at the joint where you identified the clamp. Simply seperating the two segments at that clamp and applying some grey RTV may be all you need to correct the leak. The pipes probably haven't cracked.