[Huskla]

https://streamable.com/c6q9n - E90 2006 M57 330d

Guys, I've had this skkrr skrr'ing sound on initial startup, it stays rough like this for a good 15-20mins. Once car is somewhat warm the sound goes, but it's worrying cause it doesnt sound healthy.

The car is uninsured and parked up atm so I havent taken it to a garage just yet, but any ideas what we're hearing here guys?

After some googling I'm thinking its maybe the crankshaft pulley or waterpump belt? I'm not as handy as you guys who repair your own cars unfortunately.

Any ideas/help would be appreciated.

[rasa bmw]

cannot hear anything,,sounds like a normal car,,vids are pretty hard to pick up noises unless its very loud or strange

[MrSweet1991]

Sounds so rattley :O ti be fair, what we pickup on a video can be a lot different to standing next to it. But to me it sounded horribly rattley, a quick check I would do is remove the belt and spin your pulleys see if any bearings are gone. Crankshaft pulley if gone usually makes a knocking noise I believe and you should be able to see failure from two different things, visible cracks in the surrounding rubber and the pulley wobble on startup.

And is there any reason to doubt the service history, more particularly the oil changes? While it's not a common issue on our M57's the timing chain is at the front, pretty much where your placing your phone and It does sound to me rattley. I'd check pulleys first, then use a screwdriver to listen in on the chain, if it is the chain your quite lucky to hear it and have a chance to fix it while quite a lot of people find out when its too late.

[Huskla]

Originally Posted by MrSweet1991

Sounds so rattley :O ti be fair, what we pickup on a video can be a lot different to standing next to it. But to me it sounded horribly rattley, a quick check I would do is remove the belt and spin your pulleys see if any bearings are gone. Crankshaft pulley if gone usually makes a knocking noise I believe and you should be able to see failure from two different things, visible cracks in the surrounding rubber and the pulley wobble on startup.

And is there any reason to doubt the service history, more particularly the oil changes? While it's not a common issue on our M57's the timing chain is at the front, pretty much where your placing your phone and It does sound to me rattley. I'd check pulleys first, then use a screwdriver to listen in on the chain, if it is the chain your quite lucky to hear it and have a chance to fix it while quite a lot of people find out when its too late.

I'm glad you can hear the rattley/skrry skrry sound (clearly I cant explain a sound very well lol)

But the problem is, I'm not handy enough to diagnose myself so I'd get it to a garage very soon. The service is due and mot etc, but I'm sure that cant be the reason why the rattley sound is there?

I would have to get it in a garage for someone to check the pulleys. The oil changes are legit, as I have full service history. Gearbox had a service a year ago which helps.

Quick question, that belt I'm looking at there in the video. Is the the alternator belt? Starter motor belt? I'm quite positive that isnt the timing chain right? (sorry for the newbie question do bare with me mate)

[rsvr]

Originally Posted by Huskla

https://streamable.com/c6q9n - E90 2006 M57 330d

Guys, I've had this skkrr skrr'ing sound on initial startup, it stays rough like this for a good 15-20mins. Once car is somewhat warm the sound goes, but it's worrying cause it doesnt sound healthy.

The car is uninsured and parked up atm so I havent taken it to a garage just yet, but any ideas what we're hearing here guys?

After some googling I'm thinking its maybe the crankshaft pulley or waterpump belt? I'm not as handy as you guys who repair your own cars unfortunately.

Any ideas/help would be appreciated.

Sounds like a dry v belt. Try rubbing chalk on it when running or talc power or replace it

[MrSweet1991]

Originally Posted by Huskla

I'm glad you can hear the rattley/skrry skrry sound (clearly I cant explain a sound very well lol)

But the problem is, I'm not handy enough to diagnose myself so I'd get it to a garage very soon. The service is due and mot etc, but I'm sure that cant be the reason why the rattley sound is there?

I would have to get it in a garage for someone to check the pulleys. The oil changes are legit, as I have full service history. Gearbox had a service a year ago which helps.

Quick question, that belt I'm looking at there in the video. Is the the alternator belt? Starter motor belt? I'm quite positive that isnt the timing chain right? (sorry for the newbie question do bare with me mate)

Ahh I see, well if you're not too hands on things become quite expensive unfortunately. The fact it has regular oil changed is a good sign because our engines don't really suffer timing chain issues, it can happen but it's not often they fail. I would like to mention though, it could be a few things yet but jts just something to be mindful of as if it is the chain you have the opportunity to avoid the catastrophic consequences.

The belt we are looking at is called the auxiliary belt, it runs a few things including the alternator, waterpump and also spins on the crankshaft pulley and the belt tensioner. This belt can crack and the usual sounds you get from a belt is squeaking due to it slipping for different reasons (oil on belt or tensioner failing) but from my knowledge it couldn't produce a rattle sound. To me I believe this is more likely one of the pulleys or as previously stated could be timing chain.

Now the timing chain is different from the auxiliary belt, the timing chain cannot be seen. It sits behind the metal cover that you can see your pulleys are on, the timing chain keeps the engine in time, so the chain is installed when the piston and the valves are at a certain position, put simply it ensures the piston doesn't hit the valves.. if this chain snaps it quite literally destroys the engine rapidly as the pistons will smash into the valves, bending them and various metal bits can get stuck in the cylinder and score the walls and the timing chain itself can create quite a mess and the velocity once it snaps can break something. But, I would like to emphasize again, this timing chain isn't a common issue on our engines, our M57's are solid blocks! So please don't worry too much I'm just saying as rattles can be a sign of the chain having stretched or guides failing but there's a lot more chance of any of those pulley bearings failing creating a similar sound.

Let us know what the garage says, i have a feeling it's a pulley or having listened again could be the alternator.. I think you'll be fine though