2008 Porsche Cayman S - Loud bang and white smoke!!!

Hi all, I'm new to this forum as I am seeking help with my 2008 Porsche Cayman S Automatic. I was driving on the way back home under 30mph and I stopped at a small roundabout. When I hit the accelerator I heard a large bang from underneath the car and then the exhaust started billowing out huge amounts of white smoke with a nasty burning plastic smell. I thought the car had caught fire and I turned into a local road quickly had safely whilst bursting my two left tyres on a kerb because it seemed like I lost control for a second and I wanted to get it away from other cars and people on the side of the road. I got the Cayman picked up and delivered to a garage that did work on her recently. They fixed a leak from the transmission and I am thinking could these issues be linked? I didn't have any problems with the car before that work. Any help or ideas would be much appreciated. Z

Let’s see the video

AOS ?

No video exists.

Could be. It’s in the garage and hopefully I’ll find out later and report back to you. Fingers crossed it isn’t too serious.

You may want to read the article about the cam plugs shooting out. Don’t know if it relates to your popping sound but definitely something to look into. Sent from my iPad using Tapatalk

Sounds like AOS . There is a youtuber that took his 987.1 to a track day at Laguna Seca and there is in-car and spectator video of his AOS blowing while going around turn 1. I forget the youtube channel but its an asian guy in Cali.

I’d agree AOS , might be a good thing that blew because I’ve heard of the IMS seal also popping for the pressure (my Indy shop claims)

Thankfully, AOS swap isn't a big deal. Apparently easy enough to do on one's own, so it should be fairly inexpensive for your shop to do it.

I just did my AOS a few weeks ago. It went out under heavy braking at an autocross event. I was able to drive it home ok, as it seemed like a minor AOS event. It didn't really smoke at all other than right after it happened. I was driving the car pretty gently until I was able to get it changed. It took me about 2 hours or so, though most of that was trying to get the bottom hose clamp slid over to the left. I could do it in half that time if not for that one headache. Changing to a hose clamp that tightens with a screwdriver would make it much easier. My car was also overfilled on oil (thanks to the dealership). So far I have removed about a quart, and it is still reading completely full on the digital guage. I have heard that you should have the oil level reading 3 or 4 out of the five marks on the guage. It is supposedly bad to run it at 5 of 5. My AOS was changed only 3k miles ago (3 years), according to the maintenance paperwork that came with the car. I think the overfilled oil can definitely trigger the AOS failure. It seems strange to me that yours happened under such a low stress driving condition.

I’m not gonna lie it was scary especially with so many people around and all the other cars… I thought the car was on fire. I guess I won’t know for sure that it was the AOS until the garage swap it out for a new one. I’d love to do all this stuff myself, but I currently don’t have a private drive or a garage.

The AOS is very easy to access. You don't even need to lift the car. I just kneeled/crouched in the hatch. A step stool makes getting in and out of the hatch easier. It could probably be done while parked anywhere. Provided that you are fine being parked there for an hour or two. The car being a bit warm, but not hot can make the hoses a bit more pliable. A few fliers and a few screwdrivers are probably all that you would need. I changed the small bottom hose at the same time. It was about $30 US for the hose and $120 US for the AOS , this was from FCP euro .

it’s deffo something I could most probably do. I just don’t like doing things outside my house. When I added a tracker and changed the headlight lightbulbs & foglight bulbs, I went to a local car park when it was empty… I have proper nosey & jealous neighbours.

this is why I suggest every 987 owner keep a $120 AOS in their car at all times. I was once out exploring twisty mountain roads in a deserted part of California, petrified forest, and my AOS blew. Pulled over, zero cell signal, and no traffic to speak of and the nearest town 30 miles away. I've went through 2 AOS in 100k miles. They fail if you over fill and hot oil burns through the rubber membrane or from pushing the car HARD and oil sloshing back over said membrane. Better off underfilling the cayman 2 bars to the top, never the top. Had I had an AOS and did the AOS test by putting the hand over the oil fill hole, I would have known it blew and swapped it on the side of the road. Even if you don't do it yourself, at least you have it so when you are towed to podunk middle of nowhere 1 gas station town, you have it for a mechanic to swap in.

So, I got her back today and she’s running like a dream just like before the AOS issue. It wasn’t a cheap job, AOS repair, Bore score check, two new original tyres and alloy wheel repairs and it cost me just under £1.3k. The moral of the story is don’t overfill your engines with Oil. That was one expensive mistake 😭

I've done a lot of oil changes, on many vehicles, and am always concerned about over filling. So i add a little bit less than needed, start up the engine, run it for a few minutes and check for leaks. Shut it off, leave it sit 5 minutes, and then check the oil level. Its easy to add a half liter if needed.

I ended up removing approximately 2 quarts of oil from my car after the dealer overfilled it before I took the car home. It likely caused my AOS failure. I am now at 4 out of 5 bars on the digital guage. I plan on adding a deep sump oil pan with baffles at my next oil change. Like Breanna said, I think a good way to go is add a quart to a quart and a half less than is called for. Lower the car and let it settle for a bit. Check the level cold if possible. It is always easier to add oil than remove it. I've heard that sometimes the oil doesn't drain as fully as you would like. This could cause an overfill if you add the listed amount. Make sure that the oil level is where you want and up to temp before really giving it the business.

I started her up for the first earlier today and I had no smoke on startup which is extremely positive. The garage did well here, I have to admit 👏🏻