Clank at cold start

[pbrennan10]

Starting my 93 525i results in the same thing every morning. A fast clunking that goes away after a few seconds...It's something in the engine but i dont know what. Is this a serious problem, will i need to replace something soon?

[Blitzkrieg Bob]

pop the hood, start the car get out and listen for the sound and where it is coming from.

It might be something simple, or not. but you have to indentify the source first.

[pbrennan10]

It's in the engine, one of those things down in it. It's synonymous in pace with the engine revs.

[NovceGuru]

I also have a 93 525i (9/92, m50tu) that does the same thing. (198k miles) I replaced the cam chain and all tensioners/gears at 181...made it quiet down a bit, but still nice and clanky at a cold start. i've been told by some its oil canister, some that its rocker arms, some that my car doesn't have rocker arms....etc. Honestly I have no clue what it is. It would be nice to fix but I don't know where to start. *DRIVES ON*

NovceGuru

[Kalevera]

Bob's got the idea down -- need to do a bit more to identify the source.

My first inclination is to suggest that if the noise is prominently heard in the cabin, the starter solenoid is hanging, thereby leaving the starter engaged (guess who did two starter replacements last week).

best, whit

[NovceGuru]

It sounds like its all along the valve train.

[pbrennan10]

It's heard outside just the same. It's just like hearing the engine, except instead of a hum hum hum you have a crack crack crack. It surges at startup just like the engine does, then when regular idle begins it goes away.

[Kalevera]

Hi Patrick,

That's a much better description of the sound.

I'd guess that it's the hydraulic lifters losing oil pressure. Fairly typical on cars with higher mileage -- the car sounds terrible on startup; once they pressure up, it's fine. Still freaks me out when I get into a car and crank it to hear that -- "oh man, is this thing broken or what?"

best, whit