Hi

Over the last couple of really cold morning starts my 330D E90 107k miles, i have noticed what seems to be a split second loudish crank knock immediatly the engine starts but this only lasts for about 1/2 second, then the engines sounds as smooth and quiet as usual.

Am i being paranoid or is there wear in the engine? The motor is sweet and uses almost no oil.

Your feedback/help would be much apreciated.

Thangs

Haguey

I'd just put it down to a cold start.  They can make a right racket starting when cold, my neighbours 520d used to wake me up every morning without fail last winter when it was starting.

You could try changing the oil, make sure its a quality brand and the correct spec.  When was it last changed? 

Thanks Andrew,

The oil was changed approx 8k miles ago.

I think i will change it.

Bye the way how is your 545i?

Your oil is probably about half way thru its life, if your condition based servicing is anything like mine.  Has the starting improved or have the conditions worsened out your way?  It was minus 5.5 out my way last night.

bananas wrote: Bye the way how is your 545i?

It's a beast!  Goes like stink and can return an average of 28.5mpg.

It needs a light right foot with all this snow about.  Took me half a dozen attempts to get out of my street this morning, but I got there and got to work only to find that the meeting I battled to get to has been cancelled!

Its strange, but the temperatures have not been as severe probably - zero and not minus 2 and the knock seems to have gone!

I have started to switch the ignition on and leave it for 20 secs or so before turning it over. Dont know if this makes a difference with warmer fuel on the cold  start reducing diesel combustion knock.

bananas wrote: I have started to switch the ignition on and leave it for 20 secs or so before turning it over. Dont know if this makes a difference with warmer fuel on the cold  start reducing diesel combustion knock.

I'm trying to remember from when I was inflicted with driving a 520d for 9 weeks but do you not need to wait for the glow plug light to go out before starting the engine?  I must have shut that bit out....

All the Ford diesels have a glow plug light, this comes on (at ignition position II) then goes out once the cylinders have reached the right temperature and then you can turn the key to ignition position III to start the engine.  Do the oil burning BMWs have this?  I can't for the life of me remember and I've driven several different kinds....

A failing glow plug will hinder cold starts and possibly it would contribute to the noise.  I suppose if the cylinders are warmer after leaving the igntion on for a few seconds more, will make the engine easier to start and less noisey.

I have come to realise that the knock i am certain is diesel clatter when i wasnt waiting for the glow plugs to heat sufficiently.

Each morning its recently been -10 i have waited for 20 sec with the ignition on and it starts with no knock at all!

I have read somewhere that if you crank the engine before the fuel has been warmed, the management system can initialy alter the fuel injection timing to compensate and cause the excessive knock

Certainly sounds a plausable explanation.