Turbo whine when cold..

Justintime · 24 Nov 2010 at 17:54

Took a trip with a mate up to Lincoln today in his 530D 55 plate.. i noticed upon a cold start (it was about 1C as well) the turbo produced a siren like whine/whistle for about 4 miles before eventually dying off. I commented on it and was surprised when he retorted that my 320D (06) has this exact whine in the morning too.. i think i got so accustomed to it that it didn't occur to me. I started er up, drove and sure enough it was there, went away after about the same mileage. Is this usual in cold weather or am i looking at turbo issues here? Though, honestly i asked my dad and he reckoned he commented on the siren sound last winter. I do let turbo cool and idle it for about 1/2 minute before shutting down etc.. righteously since i bought it. Oh yes, its remapped to 198bhp btw (this summer).. not felt any loss of power, just the usual diesel letarghy for the first mile or so in the cold, all diesels i owned were like this though.

Cheers!

Justintime · 24 Nov 2010 at 18:11

It goes up and down with revs.. i also only go hard on it when its warmed up (after 4 -5miles). Eventually it totally goes and no whine/whistle is heard.

Justintime · 25 Nov 2010 at 19:56

Takes a little longer for me, usually 3 miles or so, but this is in fairly slow traffic so i doubt the engine really gets up to temp by then. How the hell does one see the engine/oil temp on my car btw?

I listened carefully and the noise is still there when fully warm but much much fainter, almost undetecable if you don't know what to listen for. Drove the car again about 2 hours after i got home and the noise wasn't noticeable as the engine would still be a bit warm and its 2C outdoors now so i guess thats not bad at all, its definetly only when sat overnight and fully cold. On a side note the boost feels like a supercar in this cold lmao.

Justintime · 11 Dec 2010 at 17:32

Well, yesterday was much warmer than most days at 10C, noise lasted about 8 mins from cold when i left work and promptly totally disappeared. So its definetly temp related, likely something to do with oil. Having a look about at a few forums, it seems to be a known issue though theres no definite explanation, has happened on brand new cars as well. Theories vary from dying turbo (though this issue was there last year too so i doubt the turbo is going anywhere), some sort of vane closing under a certain temp, to metal contraction. God knows.