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My 1999 E36 323i convertible makes a strange rattling / grinding sound when started from cold. It seems to emanate from the engine bay and subsides after a few minutes. The car has only done 42K and is well looked after. What is this likely to be?:confused
 

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Have you got a rough idea of where this sound is coming from ?

It'd be quite hard to say what it was with your description, we need more info really.
 

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Thanks for response. It is quite evident and quite distinctive, when standing next to the r/h (drivers) front wing. If I open the bonnet it tends to merge in with all the other mechanical noise. Based on this I would say front drivers side of the engine bay. Doesn't seem to be a mechanical sound from a pulley or similar. Also if I park the drivers side against a wall and exit through the passenger door, as I sometimes do it is evident from the inside of the car with the windows open, presumably reflected sound. It is almost as though it stops once the oil has circulated around the engine and warmed marginally, say two to three minutes and doesn't seem to happen when the engine is warm. It also seems more noticeable if I park facing downhill. The oil level is fine and the oil is of good quality. supercass:confused
 

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Is it like a loud ticking sound ?

I thought it could be the hydraulic lifters, but I would have thought that after 2 mins, that would have cleared.

Or the VANOS unit.

What grade oil are you using ? If it's too thick, it won't reach the parts until it has thinned out abit !

Next time you start the car, put your ear close to the top of the engine, and see if the sound is coming from inside the rocker cover, or if it's coming from the VANOS.
 

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Is it like a loud ticking sound ?

I thought it could be the hydraulic lifters, but I would have thought that after 2 mins, that would have cleared.

Or the VANOS unit.

What grade oil are you using ? If it's too thick, it won't reach the parts until it has thinned out abit !

Next time you start the car, put your ear close to the top of the engine, and see if the sound is coming from inside the rocker cover, or if it's coming from the VANOS.
Thanks, Ferret and Speerzie for responses. It is more like a grating sound, quite distinctive and unfamilar in the context of a smooth ruuning six. I did wonder about the Vanos, Isn't there a valve to prevent all the oil draining back into the sump? Could this be jammed, clogged or similar? It seems as though the engine is running very smoothly, and this sound is in addition to that, so is not a rough running engine as such if that makes sense! I haven't had the nerve to rev it yet when cold, prefering to wait gingerly until the sound subsides. The oil is a 0W30 long life fully synthetic, which is a thin as it gets when cold! It should really be a 5W40 for UK but should be O.K. for this cold weather, shouldn't it? It was changed with the filter about 5k ago and since then I have topped it up with about half a litre of fully synthetic 10W40 but not of the long life variety. There is no evidence of a dodgy exhast seal, but I will have a closer look. I was wondering about the water pump and associated mechanisms. Do they get dodgy about 40k? Regards, supercass:confused
 

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It's quite hard to diagnose strange engine sounds over the internet, are you able to get a video recording of it ?

From what your saying, I think it might be VANOS, but it's abit odd that the sound stops - Does it stop completely when warm, or just quiten down ?
 

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Thanks Ferret for your response. I'll have another more careful listen when it's warm. Not sure if I could manage a video recording, bit hi tech for me. I get phased out when I don't see vinyl in HMV anymore! If it is the VANOS what do I need to do about it? regards supercass
 

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Regarding the VANOS and what you need to do... Cross that bridge when you come to it.

Let's try and find out for sure where the noise is coming from.

Try putting your hand on the VANOS area when the noise is happening, you might feel it... Have you got a friend that could take a video of it for you ?
 
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