Generally good to clean the intake

Huge plumes of white oil smoke.

I think I have an AOS replacement in my future.

I should know the symptoms by heart, but I don't. I will pull the throttle body tonight and see what is in there. Are there other obvious symptoms?
Is there a way to distinguish AOS from something else?

I know, I know I should have done it profalactically. But I am an if'n it ain't broke kinda guy..

The only thing that can dump oil into the intake is the AOS. So if the intake manifold is coated with oil, that's your culprit.

Don't run the car at all until you fix it. Replacement isn't that bad, really.



Edited 1 time(s). Last edit at 03/10/2020 06:23PM by Boxsterra. (view changes)

driving the wife's truck today.
Culture shock.....

The oil was all over - actually ponding in places.

It easily took 10+ paper towels to clean the T-section. I have to get the rear cross piece off tomorrow.

So and AOS is definitely in the offing.

You should be able to reach the AOS by taking the right rear wheel off and it's basically right there. Ok, well maybe set in a foot or so.

I think have to get both black cross pipes off the intake manifolds to clean them.
I thought there was a valve of sorts in the cross pipe next to the "T" pipe the throttle body attaches to?

There was oil pooled in the bottom of both intake manifolds. If i do not wipe it out, it will take a while to burn through the engine. no?

It was also in the air intake, so I will clean that too.

I thought you were referring to the cross-braces under the car, which are irrelevant to this job. You can remove the intake tubes by loosening all 4 hose clamps and wiggling them off. The intake manifolds are more challenging as the front bolts (near the cabin) are a little tricky to access.

It isn't totally essential that you get 100% of the oil out, just generally good because the airflow will be disturbed by the residual oil. As long as you get the pools out, there isn't any realistic risk to the engine if tiny bits of oil remain.

Yes, it will take hundreds of miles to burn all of it off.

"It was also in the air intake"? Where, exactly? It shouldn't be anywhere upstream of the AOS tube, which is by the throttle body.

There was an obvious "V" shaped leak of oil through the bottom of the throttle body flap. When removed from the air intake, there was obvious oil in the intake that was visible dark brown to the touch. I did not reach in to clean it up yet, but there is clearly more than a sheen.

Perhaps coincidentally, I was getting MAF codes last week. There was no obvious oil on it when I cleaned the MAF, but I suspect it would take very little to get a code.

I did not really disassemble everything. I was just diagnosing on a weeknight. I would say the inspection fairly clearly points to AOS. Cleaning the throttle body left a substantial oil stain on the driveway. The rubber cuffs on the "t" pipe were drenched in oil. It took multiple towels to clean each one. There was A LOT of oil in there.

I will do the repair after getting the parts and know more.

The entire oil tube would have to fill with oil before the MAF would be affected. The MAF is suspended in the middle of the pipe from the top.

If you remove the intake manifold then it is a good time to replace the 6 rubber seals. Old, flattened ones don't always make a perfect seal when put back.

I submit that with the amount of oil i observed leaking into the intake from the throttle body, there could well be micro-droplets (if that is a word) of oil that could contaminate the MAF. Otherwise the MAF codes from last week are an unusual coincidence with the failed AOS.

I am not going to remove the entire intake manifold. It is simply too big a job for limited benefit. It also has the potential to insert a new problem just by disturbing stuff that has been there 20+ years.

I will have my 11 year old stick her tiny hands into the intake with a rag to clean them out though and I will remove and clean those portions of the intake that are readily removable with jubilee clamps.

Step one - fix the obvious problem.
Step two - figure out what is affecting the MAF.

The codes are likely caused by a bunch of unexpected oil going into the combustion chambers, unrelated to the MAF. I maintain that this problem won't cause a MAF malfunction, though it won't fix one either.

I think these are all MAF codes.

P1117 O2 sensor code, bank 1 - likely caused by burning oil
P1128, P1130 O2 sensor codes - enrichment limit - aka "too much oil in the intake"

Fix the AOS and reevaluate.

It looks like a good way to spend the afternoon.

One of the most unfulfilling jobs I have ever done on a car. It would have been easy enough had the blue clip come off the clamp without disturbing the rubber bellies. But the clearance was so bad....
Three hours later and a trip for a jubilee clip later and I was back to that point.

The job was not hard per se. But the clearance was just awful.

congrats! i’ve done it twice and swear i’ll pay someone next time. no fun!

now it’s time for you to drive around a while...wondering WHEN the smoke will stop.

I remember Maurice helped me change out mine on my old Boxster as a pre-emptive measure at around 50k miles (mine hadn’t failed yet), and it didn’t seem that bad, although he basically did all the work. lol. Glad you got it done and hope that solves it.

Seems to be a lot better. No obvious smoke.
Also seems more peppy. But who knows if that is reality or not.

Really sore forearms.

I agree that getting the bellows and clamp on straight while removing the clip is the hardest part. It's possible to reach in with one arm and hold the clamp down while pulling the clip off. In that case you have to do it by feel since you can't get your arm in there at a good angle and see at the same time.

I should have mentioned this earlier but even when it looks like it's on correctly, sometimes the back isn't on straight. I use a mirror to check the back. If you have codes after a few hundred miles this would be something to check.

Believe it or not, the bellows were kinked in the back here

On my car, there is plastic wire mount in the way. Without the extension hose clamp pliers (purchased for the coolant tank) the job would have been impossible.

The rear portion of the bellows became kinked when I removed the blue clip. It might have held, but I was not willing to risk it. I tried to replace the blue clip, but no luck. I think one needs reverse pliers to spread the hoop side open.
I tried with the remote pliers, but the plastic thing was in the way. I tried to remove the plastic, but there was no clear way to do it - I am sure if'n I could see, that would have helped.

Ultimately, I got a jubilee clamp and used the 90 degree end of an allen key to seat the back. I could reach my pinky around to confirm it was seated. It took several tries to tighten the jubilee clamp, but the ratcheting screwdriver with a socket worked.

5 hours over an open clamshell is doing a number on me today though.

In a related problem, it was a bear to get the intake pipes back on. Ultimately, I had to soak the rubber (?) sleeves in boiling water for 5 minutes in order to get the sleeves to set. They had been VERY hard before. You would think that part would be easy, but not so much.

All in all, a nuisance of a job. NOT one I want to repeat any time soon - unless the engine is out of the car.

[986forum.com]

I did not want to break it, so I left in in and worked around.
I would say that without that plastic connector, life would have been easier. Much easier.

Did you lift the clam shell all the way up vertically to give you more space to work? I need
to do this job, but am somewhat torn on if to pay someone to do the work.

I also did almost the entire job from the top.

One might suggest I should have spent more time on the bottom side, But had the blue clip not slipped, it would have been a 2 hour job - including getting it into service position.
It is only when the clip did not seat properly that the problems arose.

If you are flexible and generally comfortable working totally blind, by feel alone, it is a totally doable job if you have the remote hose clamp pliers. Without that tool, not so much.
It is a total nuisance though.

you do a long job from the top, remove the clamshell. It's not hard to do and saves the back. That said, I've done this job on a bunch of cars and it has always been 90% underneath.

Being short and fat was....