Gadwood74

How can you put a 991 on neutral without keys? Car is currently on Park (PDK), need to go to the dealer for a new key (lost mine) but can get it on the towing as wheels are locked...

Update: Check engine went on again. One cat have beed severely damaged because oil went in it (certainly due to the AOS failiure). Dealer in Canada is asking 2,500$ per cat.Found 2 used cat for 600$ (perfect sape, from a car with 40,000 miles on it). Those used cats are impossible to find, at least for the 3.4L. Seems easier for the 3.6L... This means an AOS failiure must be changed rapidely to avoid this.

Thanks all for the comments, very interresting. I just had great news - no coolant in oil. 20,000 pounds less on my shoulders (and 20,000$ securized)... I just need to figure out where the coolant leek. I guess the next step would be a pressure test on the system as I never see coolant on the ground when parked. There's a couple of posts on coolant system testing.

Well, used oil didn't looked like a creamy hot chocolate, thanks god (or please god). I Will still have the oil tested next week. But I think my question was not clear enough: could a defective AOS cause an intermix? Thanks Logray for your answer, didn't thought about oil cooler. I've been driving recent and low mileage cars since the past 10 years, so it's been a while since I had mechanical problems.

Is it necessary or recommended to change engine oil after an AOS failiure/replacement? I've changed my AOS a couple of weeks ago and drove the car for +/- 300 miles. FYI-engine oil had been changed just before the failiure. However, I've changed the engine oil again tonight just in case, not sure if it was necessary. I just went for a ride and had the feeling the car was running better. Is it possible that the AOS failiure could have result into a coolant mix with engine oil?? This is what I was scared about. Maybe scared w/o a good reason!!

To replace my AOS, Isimply used the DIY from Hobbes (in the DIY forum). It was great help!!! As mentionned, I was not able to take the coolant tank out of there. Instead, I've lowered the engine a bit and everything else was easy. There was a coolant hose connector ( 996 106 226 51) that was completly dry... This should be purchased and changed, no question!! I wonder if a small plastic piece form this part going in the coolant would generate a AOS problem... One thing for sure, not too god to have plastic parts in the coolant system!!! Next step for me: abs/PMS lights comes on after a couple of minutes (everytime). I will have this checked, probably a sensor or the brake switch. Hopefully this one will be an easy fix!!

Job done! AOS was the main problem. There was also a leak from a weak hose clamp near the right front rad. So 2 different issues. I feel that engine sounds and runs better now. Didn't go for a ride yet, will do tomorrow. I'm sure I'll have a better feeling vs my first rides in a 911 a couple of days/weeks ago. Still not a good evening for a ride in a convertible; -40 degrees with the wind factor here in Montreal (F or C)!!! Tu t'ennuies du Québec Martin??

6 hours later, almost done. Lots of oil in intake. We've wasted our time trying to remove the coolant tank, w/o success. Then decided to lower the engine, everything became more simple. Let's see what will be the conclusion tomorrow!

I still wonder if I will be able to make it w/o lowering the engine a little. It is a C4 convertible, I think there's a little less room in the engine bay on convertibles. Right? BTW, it is -20°F this morning here in Quebec (-29°C). Not necessarely a good day for a ride in a convertible!!!

It seems that I will have a couple of interresting hours tomorrow night as I will begin the work. Thanks for the suggestions, I'll verify the expansion tank and the blue cap. I drove it to the garage where I'll do the work. The oil pressure gauge was travelling between 2.5 and 4. Check engine light finally came on. The exhaust was smelling a lot all the way (wife followed me, no important smoke though). Let's hope for the best!!

I Will replace the AOS. There is effectively vaccum from oil fill. I may have a separate issue with the coolant, it may not have anything to do with the AOS/smoke. I will have the radiators/hoses verified, I think I may have a small leek... The challenge is now to find a couple of hours to change the AOS!!!

Hi there, first, sorry for my english, I'm one of those from Quebec, Canada where we got over 85 inches of snow so far this winter (french canadian). I've been driving Subarus for +/- the last 10 years (mainly all turbos, Outback, Forester, WRX, Sti). I had LOTS of fun with them. I now decided to try a Porsche. I own a 996 2001 C4 convertible since a couple of days. The car has 60,000 miles (130,000 kms) on it, still in very good shape. Very proud of it, until yesterday. I had a nice small ride with my 2 kids yesterday night (4 and 6, just enough room for them!!). It was the first ride, +/- 10 miles ride. Back in my garage, I've restarted the Porsche and noticed a huge amount of white smoke off the exhaust. I've opened the engine bay. My coolant was down for +/- 2 liters (+/- 60oz). It was full, verification was made before departure. Garage floor completely dry, before and after the ride. I've then decided to look on the net (mainly this forum). I saw many posts about AOS. I'm still however not sure if a bad AOS would consume that much coolant. I expect this to be a more serious problem. Head gasket maybe? With only 60K miles on it, this would be surprizing unless the car would not have been well taken care of before. Engine ran smooth. I've started it up again today. Again, lots of smoke in the garage. Small hesitation 1 second after it was started, ran smooth after for 10 seconds. Not sure if I should drive the car or not at this point. Even to bring it to my mechanics at 8 miles away. Anyhow, I will order a new AOS to replace it after what I read. I hope this will fix the issue. Thanks to all of you for the various DYI, very helpful. Also, thanks in advance for your comments. I will keep you informed once the AOS changed. I hope I will be able to run the car this summer and have fun with it. Feeling is great, so far!!!