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      05-03-2012, 09:49 AM   #21
335i E92
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Drives: 335i E92 SE
Join Date: Mar 2010
Location: Manchester

iTrader: (1)

I’ve always used the same oil, Castrol Edge 5w 30w so I donĀ’t think it’s that.

Thinking about it logically:

What is causing white / blue smoke on start up only? Can’t be turbos as Creepy pointed out as they would smoke constantly and wouldn’t be hot enough to cause smoke on cold start up anyway.

This is has definitely got to be something that collects in the combustion chambers over night that’s ignited and instantly burned off once the engine is started. All of my injectors have been inspected and replaced so it’s not that and in any case the injectors wouldn’t cause the loss of ¼ litre oil in 400 miles.

The question is, is it possible that a faulty PCV system can cause smoke on start up only? I don’t fully understand how the system works tbh, is it possible if a PCV system is faulty that its dumping oil or blowby back in to the cylinder chambers over night, leaking down the intake maybe?

Trying to quantify where ¼ litre of oil goes in just 430 miles with no trace other than a little smoke at start up. If you break it down the has car probably seen 35 – 40 cold starts over 430 miles so it’s more than possible that its burned ¼ litre of oil on start ups alone.

Last edited by 335i E92; 05-03-2012 at 10:05 AM.