hi all, i have a 1999 porsche 996. i noticed the car blows blue smoke out the drivers side exhaust when i start it then it goes away quickly. it only does this when i start it. does anyone know what this could be? thanks, karl

 

I had a new one that did that very occasionally: one big puff that lasts a couple of seconds one start up and then nothing. When warm but not running these engines can apparently leak down a bit of oil that then gets in the exhaust upon starting.

Mine only did this when parked overnight or for a long period of time, not if, say, driven to the store and then restarted 20 minutes later -- if that occurs frequently you might have it looked at.

 

thanks for your response! ill get it looked at

 

Yes, completely normal to smoke for a few seconds out the exhaust after sitting with a horizontal engine. Oil seeps past the valves into the combustion chamber and immediately burns off on start up. If the car smokes for 30 seconds or so, then typically the OAS has gone bad.

 

thanks for your reply, Doc. since im a porsche newbie please explain what an OAS is. when i start it up in the morning after it has been sitting all night theres a huge blue cloud, and like u said it goes for about 20-30 seconds. every once in a while even after the car has been warmed up ive noticed if i punch it i can see a small blue cloud in rear view mirror. it is indeed always the driver side, passenger side stays nice n clear. the car has 83k and i was wondering if theres any way a cylinder could be gone or if i might need a valve job. im dreading a huge repair bill. are there any other things that could be making the smoke? the big cloud is something that just happened out of the blue, before that i never saw anything.
could any certain types of oil make the car smoke???
i appreciate your help, karl

 

The OAS is the oil air separator. It is a black cylinder looking thing on the front driver's side of the motor. It has a rubber diaphragm that will tear and allow the car to smoke. I have a coupe of pictures of one torn in my blog (just narrow the posts down by choosing boxster on the right). Different model, but same system.

Since it is smoking more than a few seconds, I would at least start with the OAS since it is cheaper. Hopefully that cures it. If not, then you might be looking at a valve train issue on that side.

 

i have my mechanic looking into the OAS today, thanks for all the help. is it a lot of labor to get at it? is the part expensive? where is a good source to get parts for this car, the dealer prices are expensive. if its not the OAS, and it is the valves, are we talking thousands for repair? have you heard of anyone doing the valves on this car?
thanks again for all your help, i need all the help i can get. karl

 

It is a couple hours to do the OAS, and the part should be less than $150. There are some places online to get parts from, I would hope your mechanic has wholesale accounts to get the parts from.

Yes, if it is the valves, then you are looking at a couple grand to do that job. It will also require some special tools, hopefully your mechanic has them if need be.

 

thanks a lot. ill be looking into all my options. karl

 

hi, another question. does the motor have to b pulled to get at the oas? ive read a few places online that say its a 6.5 hour job that costs around 900 and the motor has to be pulled. thanks