bd42

Hi all,

I am currently an owner of '66 Mustang. Decided it's time to try a different type of an interesting car, shopping for a 987 Boxster.
There's one available for sale not far from me. I am planning to go and have a look at it later this week. Seller claims there's only one potential problem: blue smoke on cold start.
While I know blue smoke means burning oil, I'm not fully familiar with specifics of this issue on Boxsters. Quick search refers to something called AOS?

Basically, my question is -- should this blue smoke on start be a red flag for me and should I avoid looking at the car at all. If that's an AOS -- what price to solve the problem should I expect?
PS: I am planning to take this car to a mechanic for an inspection if everything else seems ok.

A432

Year/model matters. 987.1 S (up through '08) has the potential for bore scoring and needs a scope of the cylinders to identify if that's the smoke cause.
Personally I'd only get an '09+ for the 9A1 engine vs the previous M97, but understand that's out of some budgets. Lots of posts on bore scoring M97/M96 issues here and the 997 forum.

almill13

I just recently changed out the AOS on my car, it is not a bad job and only cost $100 for the part. If the AOS went bad there is a good chance there is oil in the plenum, Take the extra time and clean this out as well. If the mechanic can determine there is no bore scoring and the blue smoke upon start up is from the AOS I would not shy away from the car if everything else is solid.

I have a 66 mustang too and the cayman is the perfect pairing to the old muscle car in my opinion. They are very opposite of each other but both very fun cars.

bd42

Thanks, this particular car is 2006 Boxster S, i.e. 987.1

bredward

For what it's worth, the risk of bore scoring is significantly higher on the 3.4L engines found in 07-08 Boxster S or 06-08 Cayman S, compared to the 3.2L found in 05-06 Boxster S.

Still, I'd recommend any buyer get a thorough PPI including a borescope for good measure. That should give a good indication of what the problem might be. AOS is most likely but in the rare event it is bore scoring, it could be financially devastating!

Schwinn

Like @A432 said, the blue smoke could be due to bore-scoring... I'd certainly have that checked out before buying it.

Spokayman

Along with the suggestions mentioned, blue smoke (oil burning) can also be caused by an overfilled oil sump.
If the smoke on startup is relatively recent (since the last oil change, etc) it is somewhat more likely to be that.

harveyf

If the seller is serious, I would think they would proactively get a PPI done. And when we say boroscope, it has to be done through the sump. So the PPI is going to cost some money. No sense in your paying for it since it is a valid question for any potential buyer. There is an excellent tutorial on bore scoring on the PCA youtube channel. Takes about an hour to watch the 4 parts but it has great info.

The engine is of course a flat 6 so when it is shut down, there is residual oil at the bottom of each cylinder. If the rings are tired or the cylinders are worn or the bore is scored, the oil can drizzle into the combustion chamber and then burns off when you start the car.

My general understanding is that a failed AOS will result in smoke more constantly as the car is running. It stands for Air Oil Separator and when it fails, it doesn't do its separation job and oil mist from the crankcase makes its way into the intake tract, where it is burned off.

There are a lot of Boxsters out there. Unless this one is really cheap and you can wrench on it yourself, I would just move on.

bd42

I had a look at the car yesterday, There was some smoke at the start, it went away a few minutes later.
Overall, the car looks interesting, I am planning to take it to my mechanic next week for PPI.

Interesting. I was looking at this video: (can't comment on how accurate it is)
The author seems to claim that AOS symptoms are smoke on startup i.e. sounds like not constant smoke while running?

bd42

Took the car to a well-known Porsche mechanic in my area. They were confident it's AOS.
Did a full PPI. Negotiate a bit. Shook hands and purchased the car.
2006 Boxster S manual with 120k miles.

"New for me" post coming soon. Thanks everyone for your help!