piston rings, valve stems or worse?

[bazzobastin]

I know these can give a little puff of smoke lasting a few seconds when they start.... But mine is bellowing out oily smoke for a good 10 seconds after it has been stood for 24hr +

Once the initial 10-15 secs have past the smoke clears and everything is ok..... Just done an oil change, replaced oil with fully synthetic 5w 40 along with new filter. (8.3L of oil)

The smoke was occuring before the oil change, I thought maybe the old oil had broken down and was passing the piston rings?

There is no sign of smoke once the car is running/warm, or if it is started again after a short period.. say 6-8 hrs

Any advice? I intend doing whatever is needed myself as i have a garage with ramps..

 

[Richard_Hamilton]

White-ish oily smoke? If so, it's likely to be the Air-Oil Separator.

Take the inlet pipe off the throttle body, open the butterfly, and look inside. If there is an oily film, it is a sure sign the AOS has failed.

 

[bazzobastin]

Ahh.. Ok Richard, thanks very much.. Is that an easy fix/cheap... or main dealer/expensive??

Thanks for the cruise control info by the way, Ive just got a 4 way stalk off of ebay for £100, so will start shopping for the other bits now. Great write up by the way!

 

[Richard_Hamilton]

Depending on the model, they are between £70-80. It also depends if it is manual or Tiptronic as to how "easy" it is. I wouldn't say it is a DIY job unless you are very keen.

Try looking in the throttle body to confirm it, and I would suggest getting a price from a decent indy to change it, as it would probably be cheaper than an OPC.

 

[bazzobastin]

Mine is a tiptronic....

I do have 2 very capable Latvian guys working for me as mechanics, Last week they stripped and repaired an Auto Box from a mazda Bongo having never seen one before!
The customer was facing a charge of £1500 from the local transmission specialist, so they saved him £1000.

Are there any manuals available online? I see that Autodata does not have any info!!!

If its an engine out job, then i need to investigate why i get a knock on hard acceleration anyway... Think i might have an engine or gearbox mount gone...

 

[Richard_Hamilton]

Believe it or not, there aren't any instructions for changing the AOS in the workshop manual. It is located right at the back of the engine compartment, on the back of the engine, at the top. (You could also call it the front!) I believe that it is possible (just) to do with the engine in place on a manual, but I'm not sure about a tiptronic. You have to remove the airbox, and intake plenum to get access, and it would probably be advantageous to lower the rear engine mountings a couple of inches.

I also think it is possible to change the front transmission mount with the gearbox in place, which sounds like it might be the clonking noise you get.

Try searching on RennTech in the 996 forum for 'separator' and 'transmission mount'. You should get plenty of hits.

 

[Peter_Bull]

If its's the AOS then from my own personal experience I would expect the whiteish smoke to be there permenantly. When mine went in the OPC last December the worksop was filled with smoke!

If it was run for any length of time (seconds) with the AOS damaged and the water went into the cylinders it would hydralisise (not sure what the correct words is here) and cause untold damage to the engine.

Be very careful