Tonight, I took my 2005 997.1 C2 to Gingerman Raceway for a SCCA Track Night In America. I've been there before in a different car, but this is the first time I've ever had this car on track anywhere. (Side Note: I have 13 years of track experience driving a 350Z, Lotus Elise and 944 race car, along with two Skip Barber racing schools.) My 997 has 64K miles on it.

Long story short: Within 2 laps oil temps soared to 260F. I continued the session with short shifting and taking turns in 3rd instead of 2nd gear. This managed to bring oil temp down to a steady 250F. Since Mobil 1 starts breaking down at 260, I thought this was OK to finish the session. After the session was over and good cool down lap, I brought it in, shut it down, and lifted the boot lid to let it cool more. After about 10 minutes, I started it and got a fair amount of white smoke for about 2 - 4 seconds. Then it stopped. I shut it off and let it sit longer. Oil temps were down to under 200F. Started it again after 5 minutes and again white smoke for a few seconds and then it clears up. This kept happening for the rest of the night (I only did the one session).

I have no error codes other than brake sensors from the brake temps - which is fine. So my question is: Do you think I blew a head gasket or cracked a cylinder?

 

Anything anybody could tell you at this point would be purely speculation. It would be my recommendation to get a leak down test.

 

Most likely neither.

You just encountered an overwhelmed AOS which loaded up the intake with oil.

And you may have hastened the demise of the AOS. They don't last forever you know. (My 2002 Boxster is on its 3rd one.)

If so you'll see billowing oil smoke upon cold start and the smoking won't stop. If you observe this then the AOS is gone and you need to shut off the engine and arrange to get the car to a qualified shop to have the AOS replaced.

I would have let the engine idle a few minutes and I would have left the engine compartment lid closed. The engine compartment fan works better to remove heat from the engine compartment if the lid is left closed.

If you track again show up at the track with *fresh* oil. Do not overfill the engine but don't show up a few bars short of an engine full of oil either. High RPMs and high G-forces work to keep more oil in the engine in suspension and this lowers the oil level around the pump pickup. If the level gets too low the oil pump can suck up some air -- more likely just foamy oil -- but still this ain't good.

Take a cool down lap or two and then in the pits let the engine idle until the coolant/oil temps are down to near "normal".

 

+1 on the AOS....seen this twice on 911s (not mine)

 

AOS failure is the most likely culprit. Cheap $200 part but 4X that in labor to swap it.

 

Thanks everyone. I've ordered a bunch of stuff to hopefully address the short term goal of not smoking and hopefully be a little cooler. I'm also interested in the long term goal of not getting above 230F on track no matter what. I've thrashed cars in 95F ambient temp at redline for long periods without getting over 225F, so it should be doable. I've got to believe other 911 owners who track theirs have some solution.

Here's what's coming so far

 

You should probably use a different water pump. The metal impellers will destroy an engine upon WP failure unlike the plastic OEM style impellers.

 

I appreciate the suggestion, but I guess I don't see how. I thought about it and I got the brass one because brass works fine with antifreeze without degrading. The only downside I could think of is rotating mass.

 

Mobil 1 doesn't break down until well over 300 degrees. 260 is expected with many C7 Z06 owners.

Doesn't mean something wasn't wrong, but at 260 degrees you're okay from an oil standpoint.

 

Have you thought about changing to a heavier weight oil? I have never been a huge fan of Mobil 0w40 as it sheers to a 30w oil rather quickly. I prefer Shell Rotella T6 0w40.

 

I'm basing my statement about 260F breakdown temp on this link (and looking at it again, it seems it's 265). The post seems pretty legit, but I admit I have nothing else to back it up.

I have thought about it, but based on that oil performance test I linked to, and on the fact it's what the engineers at Porsche recommend, I'm going with the Mobil1 0w40. Before deviating, I'd have to see some reasonable evidence that the OEM recommendation isn't good enough.

 

See Jake Raby's comments here (Flat 6 Innovations): http://rennlist.com/forums/996-forum...-or-metal.html

WP bearings fail, not the impeller. But a WP bearing failure with a metal impeller can destroy the crankcase beyond repair as the impeller gouges out the crankcase. It then becomes a $25K+ engine replacement problem. This is why Porsche uses a plastic impeller. Go for a better WP bearing if you can find it but stick with the plastic impeller. Or be extra careful and proactively change out the WP again in about 40K to 50K miles.


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You talked me into it. I just cancelled the brass impeller version and ordered a composite one. I hope you're happy.

 

This exact thing happened to me at the track. It was the Air oil separator.

A while back I knew my air oil separator was probably going to need to be replaced. After spirited driving and parking the car I started to get a little smoke from the exhaust the next time it was started. I also started to hear a squeeling/whining sound that I thought for sure was the serpentine belt. Very subtle sound/whining at first as I would come to a stop in traffic. I replaced the belt and put an order in for a new aos. I went to a track day and after some really fun racing and pushing the car hard I came in and did the exact cool down routine you have. Upon next start up the car blew so much white smoke that everyone in the paddock thought I blew up my engine. The aos separator was completely overwhelmed and really on its last day.
While I was waiting for aos to arrive in mail I went for a spirited drive and the squealing sound increased to a point where i thought it was a whining belt sound coming from an old car next to me! The sound only comes when idling at a stop. Goes away when accelerating. So this was a first and interesting to me that some times when the AOS is shot to hell it can also cause a whining/whistling sound when it is really ready to be replaced. I just want to confirm that after replacing the AOS that the sound was gone and no more white smoke.

Hope that is it and you can just chalk this up to a regular maintenance issue and not something more severe. Keep us posted!

 

Install a third radiator