E90 320i (N43) engine clatter at 2k rpm when cold
Discussion
Hi Guys,
This has started recently and it's getting concerning.
Start car up from cold, sounds fine at idle. Drive down the road, after a couple of minutes, say when in 3rd gear around 2000rpm, a metallic tapping/clattering noise builds up then dies down after a few seconds. Then it starts again after a few seconds and repeats. It's like having an extra engine under the bonnet that sounds like a tappety 80's fiesta engine that is being revved up, i.e the noise is detached from the actual rpm I'm doing. Tested it this morning doing a steady speed, 2000rpm when cold, noise builds up then dies away, repeats every 5 seconds or so. After about 10 mins drive the problem goes away completely.
I'm worried it could be chain rattle, is it possible for the chain tensioner to slacken then tighten intermittently when driving causing chain noise to come and go? are there any common faults that could cause this sort of noise, like auxiliary belt driven parts or tensioner?
No noise at idle or when warmed up. Hoping it's something external on the engine, if anyone can shed any light that would be great.
This has started recently and it's getting concerning.
Start car up from cold, sounds fine at idle. Drive down the road, after a couple of minutes, say when in 3rd gear around 2000rpm, a metallic tapping/clattering noise builds up then dies down after a few seconds. Then it starts again after a few seconds and repeats. It's like having an extra engine under the bonnet that sounds like a tappety 80's fiesta engine that is being revved up, i.e the noise is detached from the actual rpm I'm doing. Tested it this morning doing a steady speed, 2000rpm when cold, noise builds up then dies away, repeats every 5 seconds or so. After about 10 mins drive the problem goes away completely.
I'm worried it could be chain rattle, is it possible for the chain tensioner to slacken then tighten intermittently when driving causing chain noise to come and go? are there any common faults that could cause this sort of noise, like auxiliary belt driven parts or tensioner?
No noise at idle or when warmed up. Hoping it's something external on the engine, if anyone can shed any light that would be great.
Any N43 with over 30'000 miles has potential for chain problems. The guides break up, chain goes loose, jumps etc.
You need to get the cam cover off sharpish and inspect it all very carefully. If the rails are still okay you can change the chain and guides with the sump on. If they're broken up (not just snapped but bits missing) then you need to drop the front subframe to get the sump off. At then time we wondered what could possibly be worse than an N46 - BMW provided the answer!
You need to get the cam cover off sharpish and inspect it all very carefully. If the rails are still okay you can change the chain and guides with the sump on. If they're broken up (not just snapped but bits missing) then you need to drop the front subframe to get the sump off. At then time we wondered what could possibly be worse than an N46 - BMW provided the answer!
Cheers for the replies.
I take it checking the tension at the top of the chain through the oil filler hole isn't a good enough indication of the chain being ok?
Forgot to say it's a 2010 with 75k on the clock, had hoped later models would of had better chain and guides etc.
Typically since the weather has warmed up a bit, it's not making any noise now!
What's involved in getting the cam cover off, do the injectors etc have to come out?
Thanks.
I take it checking the tension at the top of the chain through the oil filler hole isn't a good enough indication of the chain being ok?
Forgot to say it's a 2010 with 75k on the clock, had hoped later models would of had better chain and guides etc.
Typically since the weather has warmed up a bit, it's not making any noise now!
What's involved in getting the cam cover off, do the injectors etc have to come out?
Thanks.
Just an update if anyone reads this, the chain noise was fixed by replacing the timing chain tensioner with a new genuine one 
Engine is very quiet now - the new tensioner fitted was a revised design (visually the same but end of part number is different) so they've obviously had some problems with it sticking or not operating properly.
Engine is very quiet now - the new tensioner fitted was a revised design (visually the same but end of part number is different) so they've obviously had some problems with it sticking or not operating properly.
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