Blowing LOTS of smoke - 986 Forum - The Community for Porsche Boxster & Cayman Owners

grandmasterwayn · 10-28-2016, 07:52 AM

So I was on the highway this morning and my bosxter s started billowing more smoke than a steam engine train. It looked and smelled like it was burning oil and my boss agrees and thinks it may be the head gasket. It was idling funny for a couple of days, not sure if that's related at all. It didn't overheat or anything and the oil said it was still full if that matters. I guess what I'm trying to ask is how ****************ed am I?

Also, Hi! I just joined this morning.

Fintro11 · 10-28-2016, 08:41 AM

Check your air oil seperator

Racer Boy · 10-28-2016, 02:26 PM

Yep, probably the AOS (Air Oil Separator). The part is under $150, but the labor to replace can be a lot higher. Take it to an independent shop that specializes in Porsches. And don't drive it! Have it towed. If it sucks too much oil into the engine, it can hydro-lock, bending the connecting rods. That would mean a new engine.

grandmasterwayn · 10-31-2016, 10:43 AM

So I had it towed to the mechanic and after they looked at it they said I need a new engine. Looks like I'm 12,000 dollars ****************ed.

barkinfool · 10-31-2016, 01:42 PM

is the mechanic a porsche expert? if not, get another opinion.

Gelbster · 10-31-2016, 08:26 PM

You got the answer in Post #2
Forget your Boss and the cylinder head gasket
If you want the names of some Porsche M96 Indies in Vegas ask here.
Taking an M96 anywhere else is umm ....silly.

jb92563 · 11-01-2016, 06:40 AM

Typically an AOS failure does not hydrolock an engine very often, although it is possible.
In retrospect I should have shutdown immediately and got a tow home just to eliminate the hydrolock potential as the cost/risk ratio is too high to take a chance.

I drove a couple miles billowing tons of smoke and there were no serious side effects. It looks spectacularly bad when most cars blow that kind of smoke but is not that big a deal really for a Boxster.

We have all learned to hate the AOS after such an embarrassing event.

When it happened to me I had already read about it so I was not overly stressed and I actually started laughing at the ridiculous amount of smoke I had generated, literally blacking out a good 100' behind me and the terrified look of other drivers passing by.
Lost about 2 quarts of oil during that failure.

I simply replaced the AOS and everything was back to normal.

I would get a 2nd opinion on the blown engine theory from a proper Porsche Mechanic.

grandmasterwayn · 11-01-2016, 07:19 AM

I spoke to the guy again and asked him about the AOS. Dude said they checked that first and it was dry. He wants to start a complete engine teardown to find out exactly what the problem is but just that is gonna run me three grand. The mechanic does a lot of work on european cars and has done work on my porsche before. The things he fixed haven't broken yet.

stelan · 11-01-2016, 07:54 AM

Aos being dry does not mean anything, it means that it had time to drain. It ca still be the aos, check for intermix that is the easiest way to see if its a head. Then check compression that is the easiest way to seenif you have a broken or worn ring(s)
Or if you want to believe your mechanic and want to burn money let him do it's thing

JFP in PA · 11-01-2016, 08:05 AM

Quote:

Originally Posted by grandmasterwayn

I spoke to the guy again and asked him about the AOS. Dude said they checked that first and it was dry. He wants to start a complete engine teardown to find out exactly what the problem is but just that is gonna run me three grand. The mechanic does a lot of work on european cars and has done work on my porsche before. The things he fixed haven't broken yet.

Ask him what vacuum level did he read when he test the AOS; if he says he did not check it, or has no idea what your referring to, be very afraid and take the car somewhere else...........

That986 · 11-01-2016, 08:09 AM

Checked under the oil cap?
Oil slick in the coolant?

Rough idle and then blowing smoke looks like an AOS to me. Mine just got replaced and made a huge difference. The other thing to look for is a filthy throttle body where the oil has gathered.

Gelbster · 11-01-2016, 12:44 PM

"my mechanic works on European cars...." therefore he is smart about the M96 ?

Oh , if only that was the only qualification necessary to be a competent on the M96 !

A "dry" AOS ? That would be a first.They all have some oil residue in them -except when new in the box. Or did he mean water? In which case he is confusing it with a 996.And it is a meaningless test anyway!
Gentle hint: What did the water manometer reading say?
Gentle suggestion: Go to a Porsche Indie who uses one or at least knows the hack alternative test for AOS failure.
Please understand we are trying to help you and save you money here.

jb92563 · 11-02-2016, 12:45 PM

To save money let someone who knows how to test the AOS and other diagnostics take a look first.

Even us DIY mechanics know the symptoms of a malfunctioning AOS and some ways to test it that an indie can do for a couple hundred at most.

When I removed my blown AOS it did not leak any oil.
The throttle body did have some oil residue but not much.

A broken head gasket will cause oil and water to mix and will look like a milkshake on your oil dipstick. If oil got into the cooling system then you would see oil in the coolant and also know something internal to the engine failed.

A compression test will tell you if your piston rings are OK, which is another possible way to blow lots of smoke.

A good mechanic could do all those tests in a couple hours and not even have to open the engine to narrow the possible causes.

So what we are telling you is you have the wrong mechanic who is most interested in your wallet and seeing how much he can extract from it rather than narrowing down the possibilities and investigating the cheaper modes of failure first.

JFP is a mechanic and one of the wisest/experienced contributors here so pay attention to his advice.

stelan · 11-02-2016, 04:08 PM

Quote:

Originally Posted by jb92563

To save money let someone who knows how to test the AOS and other diagnostics take a look first.

Even us DIY mechanics know the symptoms of a malfunctioning AOS and some ways to test it that an indie can do for a couple hundred at most.

When I removed my blown AOS it did not leak any oil.
The throttle body did have some oil residue but not much.

A broken head gasket will cause oil and water to mix and will look like a milkshake on your oil dipstick. If oil got into the cooling system then you would see oil in the coolant and also know something internal to the engine failed.

A compression test will tell you if your piston rings are OK, which is another possible way to blow lots of smoke.

A good mechanic could do all those tests in a couple hours and not even have to open the engine to narrow the possible causes.

So what we are telling you is you have the wrong mechanic who is most interested in your wallet and seeing how much he can extract from it rather than narrowing down the possibilities and investigating the cheaper modes of failure first.

JFP is a mechanic and one of the wisest/experienced contributors here so pay attention to his advice.

+1 on JFP advise (he shares his valuable experience for free here)

grandmasterwayn · 11-03-2016, 10:24 AM

I know you guys are helping me and I appreciate it a lot. I'm pretty new to the whole porsche game and I really don't know engine stuff. I'll call him back today and ask if he did those tests you guys mentioned. Again, thanks for your advice!

jb92563 · 11-04-2016, 06:33 AM

All we ask in return is that you update the status of your issues, good or bad as we all learn from the feedback.

Thanks and good luck!

grandmasterwayn · 11-04-2016, 12:30 PM

So I spoke to the mechanic again and asked the questions you said. He said the engine has low compression and he thinks it's either the head gasket or the piston rings. He also said that it would be about 24 hours of labor to get to those parts to see them. I have some service contract which would cover the rings or the pistons but they wouldn't cover the gasket.

Gelbster · 11-04-2016, 12:42 PM

A competent M96 mechanic(not me - yet !) knows that cylinder head gasket failure is unusual on an M96. "Intermix" ,yes, but that is cracking of the head, not a gasket failure. So I am skeptical about both the diagnosis and the competence of the mechanic on the M96 .
If it really does have a failed gasket, the specific test is simple -no disassembly required.
Cylinder bore problems - Mechanics 101 says do a leakdown test.Cheap and easy. While he is removing spark plugs he will clearly see signs of any cylinder head/coolant/oil leakage.
Cracked bore - borescope in some situations but this is also unlikely.
Pistons seldom fail.
But it seems the Mechanic is flailing ?

JFP in PA · 11-04-2016, 01:09 PM

If you have a failed head gasket, it would be the first one I have ever heard of. These engine's use multilayer steel head gaskets that are actually stronger than the cylinder heads or engine cases.

JFP in PA · 11-04-2016, 01:10 PM

Quote:

Originally Posted by grandmasterwayn

So I spoke to the mechanic again and asked the questions you said. He said the engine has low compression and he thinks it's either the head gasket or the piston rings. He also said that it would be about 24 hours of labor to get to those parts to see them. I have some service contract which would cover the rings or the pistons but they wouldn't cover the gasket.

What compression pressures did he see? He should have given you a table with pressure by cylinder.