Sort of fluttering tapping noise.
 

Hi, I have a 2004 MK 2 Rover 75 113,000 kms KV6 Auto Petrol. Usual inlet manifold clatter which I can live with. Had timing belts etc changed at 85,000 kms. For the last 10,000kms or so has developed more like a back ground flutter tapping noise, hard to describe !!! more audible from inside the car when driving. I cannot really hear when listening to the engine under bonnet due to the inlet manifold rattle. Noise more noticeable under acceleration and less so when I take the foot off the accelerator but still there. Not what I would call a significant noise but over the last 6 months seems to becoming more audible and consistent. No change in engine performance that I have noticed. I am thinking something to do with fuel delivery. Any ideas welcome.
Cheers
Jeffrey
Sunshine Coast QLD Australia.
:shrug:

Crank pulley rubbers are known to fail causing similar noise. See if you have much rock on the pulley. Also check for loose or deteriorating belts which can flap/catch on plastic covers (sometimes caused by failing auto tensioners).

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Thanks Barmy. I will take to my local mechanic, not sure about the crank pulley. You don't think fuel injection can cause a similar noise?

when the belts were changed were the rollers and tensioner pulleys done ? if not then that would or could be a concern depending on their current condition. the crankshaft pulleys on the kv6 are not normally prone to breaking down . that prize goes to the diesels as being the usual casualties of pulley failure. there is also on the kv6 crank pulley a guide washer fixed to the toothed belt drive gear behind the main pulley that can come unatatched and rattle slightly . some members have sprayed water on to a failing pulley whilst running and noticed it quieten down for a while to diagnose this . it quietens down the rubber on the pulley for a while if indeed this is the problem. you could also undo and try running the engine for a few moments without the auxillary belt atatched to rule out compressor pulley and others on that belt. but beware that its removed away from the bottom crank pulley because if it gets caught on the bottom pulley and pulled in .... game over !!! :eek:

:wot:

It won't be fuel injection Jeffrey.

Just developing xsport's suggestion further, the ancillary drive belt also has a tensioner and idler pulley. At the same mileage as your car has covered, my belt developed a crack across all five ribs to the full depth of the rubber which caused a rattling noise.

Simon