[AndyVR]

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, ie the noise is detached from the actual rpm I'm doing. Its not incredibly loud and is hard to hear with the radio on. 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? The chain feels taught when pryed at with a screwdriver from the oil filler.


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.

[filiplat]

Did you solve the problem? Anything else happened?

[Donnie2000]

I had a similar rattle at about 2k rpm. Solved with new chain tensioner. 07 n43 60k miles.

[AndyVR]

Just last weekend I fitted a new genuine chain tensioner, so far it seems to of cured it, engine much quieter now when cold, sounds the same as it does when warmed up (75k miles)

The old tensioner wasn't bolted up very tight, it looked like it had been replaced before.

The one that came out was revision -03, the new one was revision -05, so there has definitely been some issues with these tensioners. From the outside they look exactly the same.

It cost £40 delivered from Cotswold BMW. Just needs a 27mm socket to fit.