smoking when first started

[mwadams]

Don't think there is anything wrong, but had to ask

Use the car everyday, but when she is first started and idling there seems to be a lot exhaust smoke (that's the best terminology I can use), but once the engine is warm/hot none whatsoever.

Any ideas ?, should I be concerned ?

Thanks....... Happy New Year all of you ...... Mark

 

[Andy Roe]

Most likely condensation in the exhaust at this time of year if it's white smoke - steam. If that's the case, then nothing to worry about.

 

[mwadams]

Hi Andy,

That what I think the exhaust smoke is (steam).

The car is used daily (average 30 mile run weekdays) so why so much condensation ?

Thanks

Mark

 

[Dave Wilkinson]

Mark,

As Andy said - it's all perfectly normal. When the engine is cold the exhaust gases - which comprise a large proportion of water vapour - will condense within the silencers, giving rise to the plumes of water droplets you are seeing as "smoke". Once the engine has been running for while, the exhaust system heats up and is no longer cool enough to force the condensation - hence, no water droplets. You can often see liquid water literally dripping out of the silencer. The colder the outside temperature, the more obvious the condensation - hence the fact that it's more noticeable in the Winter months.

This is one of the reasons why short runs are not good for the car since the condensed water in the silencers will accumulate if not heated sufficiently and will ultimately cause the silencer to rot from the inside. Once the engine (and silencers) get to a working temperature any excess water will be boiled off, leaving the silencers dry and potentially rot-free. Your 30 mile run (15 each way?) should be plenty enough to get the temperature up to avoid any problems. I'd guess it's just about enough to get the engine oil up to temperature too.

Regards

Dave

 

[mwadams]

Dave, Andy....

Thanks, just me being paranoid I think and worrying too much.

Yes it is a 15 mile each way trip to work and the car averages 250~300 miles a week total including leisure.

Mark

 

[Melv]

You'll get a lot of that this time of year -the exhaust gas from a 964 seems particularly hot compared to many, hence the white smoke.

Don't want to alarm you, but you will also get a bit from unburnt oil lying in the bores -that's the nature of a Boxer engine.

Mind you, don't complain -the smoke screen laid by my Pajero on cold start would hide the Graf Spee......[]

 

[Guest]

Hi Mark
would have thought you would be safe to assume the smoke is only steam on warm up or could be a bit of oil some times found on start up due to design / nature of 911 engine. poss recomend just checking oil level ( for peace of mind )