Help! oil in throttle body and tuner pipe

[frenchy2001]

Hi there, I'm new to the forum and am wondering if I can get some help? I have a 2000 boxster s 6 speed, and the initial problem was that the rpm's were hunting at idle. So I pulled the throttle body off and noticed that there was a carbon and oil buildup in the throttle body. I investigated further to find that the oil sluge made it all the way to the tuner pipe (the one with the butterfly) and intake manifold:( It looks like the oil is comming from the crank case venting tube which is connected just after te throttle body. I have since cleaned the sluge off everything that I could reach without taking off the intake manifold, which made a huge difference with the throttle response and idle.

So the big question! Is it the oil air separator? or is it that PVC type valve where the crank case hose comes from? or is it something else?

I don't want this to go on and make the problem worse. Plaese, any help would be greatly appreciated.

frenchy

[Rodger]

It sounds very much like the air/oil seperator has failed. It's about $100 to replace if you DIY.

[frenchy2001]

It sounds very much like the air/oil seperator has failed. It's about $100 to replace if you DIY.

Thanks for your quick reply Rodger:) I was just looking at the service manual and noticed that the oil suction pipe will need to be removed and the bolts holding it will have to be replaced. The 2 bolts that need to be replaced are hexagon-head bolt M6 x 20 (micro-encapsulated). Do you have any idea what micro-encapsulated is? Do you think I could reuse the bolts although it says not to. If they need to be replaced where could I find the part number. Also can I use any high heat silicone?

thanks again:)

[Loren]

Do you have any idea what micro-encapsulated is?

Micro-encapsulated means the bolts have a sealant on the threads that once used they can not be reused. You should always replace these type of bolts whenever they have been removed.

[frenchy2001]

Thanks alot Loren. Now I've added the new term to my mechanic vocab. I guess loctite won't work then? I'll take some pics along the way to make it easier for the next guy to do the job.

cheers :cheers:

[Rodger]

Loctite should be fine.

I'm going to replace my AOS very soon (probably next week) since it's leaking at the o-ring (not the bellows) and I'll probably replace my oil filler pipe at the same time, since it's cracked.

[frenchy2001]

Rodger or anyone else who might know, I was looking for the air oil seperator and I found this PVC part called the oil seperator (attached pic). Could this be the faulty part? I wouldn't take the oil pan off if I don't need to. The oil is comming directly from the breather hose off the oil seperator. What do you think?

[Rodger]

That's the air/oil seperator. I just ordered one for my Boxster from Sunset Imports in Portland, OR.

It looks easy to replace from above if you've got thin arms and can reach the two bolts that mount it to the engine. You've also got to have a razor blade to cut off the old bellows, then it's just a matter of wiggling it out of the engine bay.

If you remove the protective plate covering the transmission, you can get quite a bit of access from below.

[frenchy2001]

Rodger, thanks for the input. I was looking in the service manual and the air oil seperator is inside the engine. So I guess the oil seperator is on the outside of the engine. I was just wondering how serious my problem is...... I'll recap.

When I removed the throttle body there was some carbon but mostly a sludge (oil and carbon) build up which was mostly damp with oil in the tuning pipe and manifold. The build up was so great (about a 1/4" thick) that it it was blocking the vacuum hoses attached to the rubber sleeves of the tuning pipe. However the sludge was wet with oil closer to the crankcase breather hose connection / throttle body.

Now I've been driving the car for a couple days and removed the throttle body to find a light spray of oil where the sludge was. The car doesn't puff any white smoke on start up or under heavy acceleration. Should I still be concerned about the oil? Given my knowledge about engines I would say that oil going into the combustion chamber is not good. Any extra thoughts?

Thanks in advance.

[Rodger]

The quantity of oil in the intake is going to be relatively proportional to the amount of blow-by occurring in the engine. If you've got a fresh engine and the clearances are still tight, I would expect the amount of oil to be minimal. In a very worn engine, there may be significant blow-by, which would put more oil into the intake. Most engines use a simply check valve-type device to control crankcase ventilation. Because of the design of the boxer engine, a complicated oil seperation device is needed in order to seperate the blow-by gases from the oil vapor that may be present. Either that, or Porsche likes to over-engineer PCV parts. As the AOS internals start to fail, you may see more and more oil in the intake.

Considering the relative ease of changing the AOS, and the cost (about $100 from Sunset Imports), I'm changing mine simply for the peace of mind. I have absolutely no evidence of failure (internally), just some oil leakage around one of the o-rings at the base.

When the AOS fails catastrophically, massive amounts of oil may be dumped into the engine. Also, some cars have the bellows fail at the base of the AOS, which causes CEL codes similar to a bad MAF.

You may change the AOS and still find oil vapor present in the intake. I don't know what the standard is for blow-by, but I suspect some oil is acceptable.

Side note: after I replace my AOS, I'm going to cut it open to see how it works.

[John V]

No need to remove the lower chassis plate. I did my AOS this weekend in about an hour, working from above and below.

1) Remove the hose going to the throttle body at the AOS.

2) Remove the two bolts from below.

3) Cut the bellows

4) This gives you enough wiggle to pop the AOS loose from the engine at the o-ring.

5) Remove the "middle" hose

6) Move the wiring harnesses out of the way and pull out the AOS.

Messy, but not difficult.

[wdonovan]

Side note: after I replace my AOS, I'm going to cut it open to see how it works.

Rodger, you could clear up some of the vast mystery surounding this part if you found

the kindness to snap a few digital shots of this highly offensive part and post them here.

What thinks?

[Rodger]

I've got my bad one handy, I just need a dremel to cut it open. I guess I know what today's project is.....

http://www.renntech.org/forums/index.php?showtopic=13963

[Rodger]

I cut it open! See here:

http://www.renntech.org/forums/index.php?showtopic=14000