Excess smoke on start up - 2.5i N52 engine

C

craig_p

New member
 Dunfermline, Scotland
Afternoon all. I’m looking for some ideas of what could be causing the excess smoke from the exhaust on start up. It generally doesn’t happen when starting from cold but if the car has been running then left to sit for anything up to 30 minutes there is a LOT of grey smoke when the engine initially fires up. Once the car is up and running it appears to be fine.

I’ve also noticed a lot of black specs up the bumper just above the tail pipes and wondered if this is also pointing towards a potential problem (as I have only ever seen this on a diesel car before)?

The car is a 2006 with 42,000 miles on it and I’ve never experienced anything like this on my E46 with 2.5 times the mileage so I have partially ruled out wear and tear as the factor

Since the car is on the variable service intervals it has not had the oil changed since November 2009 (within the 2 years BMW state) and only travelled approximately 7000 miles in this period. Could the problems listed above simply be attributed to the car needing some fresh oil?
 
Do you do lots of short runs? if so it could be a blocked breather because of to much moisture build up,, you have all the symptoms of that, take the oil cap off and see if you have the old gunk problem, that will tell you, if so take it to an independant and it can be easilly sorted, DO NOT go to bmw they will tell you for that problem you need everything renewing, flushed through etc

when i had the same issue - BMW £575 plus VAT, Independant £70 including,
 
Thanks for the reply.

Generally during the week the car either sits in the driveway or does the occasional short run to the train station. The excess smoke (and I mean a lot of smoke, not just a mere puff out the exhaust) seems to be happening after long runs or when it's been driven harder and operating up to temperature.

I've also got a 325ci which gets used for the exact same journeys and had no problems so I thought this was a good base for comparison. I was wondering if the N52 engine had any issues like this in general as the M54 unit seems to be bullet proof?

My main concern at the moment are the cats as I don't want to damage them if I have this coming out the exhaust.
 
Just my two penneth,

quite simple - white smoke usually indicates water, ie head gasket (simple checks such as water loss, pressure test), blocked breathers etc as rusty says, black smoke usually is excess / unburnt fuel. The black spots could be carbon deposits being "washed" through the exhaust possibly and not a cause for concern.
 
craig_p said:
Thanks for the reply.

Generally during the week the car either sits in the driveway or does the occasional short run to the train station. The excess smoke (and I mean a lot of smoke, not just a mere puff out the exhaust) seems to be happening after long runs or when it's been driven harder and operating up to temperature.

I've also got a 325ci which gets used for the exact same journeys and had no problems so I thought this was a good base for comparison. I was wondering if the N52 engine had any issues like this in general as the M54 unit seems to be bullet proof?

My main concern at the moment are the cats as I don't want to damage them if I have this coming out the exhaust.
Click to expand...

Yep sounds exactly the same as mine,, long run, start the engine big plume of white smoke, mine turned out to be a blocked breather, no idea about comparable engine etc
 
You must log in or register to reply here.
Back
Top Bottom