'04 E53 - Puff of blue smoke on startup 3.0d - diesel
 

On startup, I can see a puff of blue/white (certainly not black) smoke coming out of the exhaust but clears up just as quickly. Is this normal? It does not seem to matter whether it is in the morning (as in cold weather) or later in the day (warmish weather).

I hope it is 'cause mine does the same...

2006 3.0D (M57TU D30) 90,000kms

I put it down, in part, to the poor quality diesel I have to use (no low sulphur here), but I do believe it is normal for all diesels to smoke a little if the engine is not at operating temperature. It is something to do with the fact that diesel does not initially burn clean until a certain temp is reached. The smoke we get should smell like diesel smoke and not oil smoke, if you can tell the difference!

One or more glow plugs have probably given up, they wear out in time. Another cause would be the preheating control box that controls glow plugs. You might want to check error codes to verify this.

I hope not. Start normal and easily. No error codes. Recently uploaded a Bluefin Superchips remap which gave the car a bit more kick and a lot smoother as well. :thumbup:

Perfectly normal for almost all diesel engines. I have owned 7 diesel powered vehicles over a period of 20 years and every one gave a small puff of smoke on first starting with a cold engine because it takes a few moments for the engine to run smoothly and all ensure that all the fuel on every cylinder burns fully. The ECU electronics will initially give a larger dose of fuel to 'help' the engine start. You may also notice your mpg or km/l figure drops at the same time but quickly recovers to where it was.

If it continues beyond a few seconds and it smells of engine oil or your fuel consumption increases permanently then worry about it. Regardless of glow plugs operating or not - most don't if the air temp is above 5deg - you will almost inevitably get a puff of smoke. A warm/hot engine rarely will smoke unless there is a problem. Watch your engine oil levels too - 3.0D units typically use around 0.5 litre/1000 miles.

I believe the latest designs of diesel powerplants (in Europe to meet Euro V regs)) use particulate filters to remove/reduce this.

Spot on. Thanks for the information. :D:D:D:D:D:D

My '05 3.0d will smoke a little on cold start-up in winter (often at or below zero degrees centigrade here) but not for a warm start up.

Just to clarify glow operation in M57N (DDE 5.0/5.1). They actually operate with coolant temperature up to +25C even if you don't see the message on the instrument cluster. Air temp doesn't affect the operation. See quote from TIS below.

My 3.0d puffs smoke at the start and I get error code from all the plugs indicating that the control module isn't working. I'm planning to change that and possibly all the plugs. I'll report if it has any affect on smoke.

From TIS:
Preheating

At coolant temperatures below 25°C, there is a preheating period of 0.5 seconds. The preheating period increases as the temperature falls, reaching a maximum of 2.7 seconds at a coolant temperature of less than -25°C.

Activation of the glowplug system on the instrument cluster only occurs at coolant temperatures below 0°C.

After-heating

At coolant temperatures below 30°C, there is a temperature-dependent after-heating period to improve idling and exhaust emission characteristics.

Start preheating

Start preheating takes place for approx. 10 seconds if after the preheating time has elapsed the engine is not started and the ignition remain on.

My is the same too. Especially more noticable when sitting for more than a few days.

Control module and plugs now changed. I'm happy to report that it had an affect on smoke. Certainly there still is some smoke for few seconds on cold engine (which is pretty normal for diesel as X5Sport earlier explained) but that big puff is now gone.