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Strange engine noise from a V6 ?

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3K views 10 replies 8 participants last post by  Chrisv6 
#1 ·
Hi All,

I have noticed a noise coming from the engine of my V6, which is only apparent on acceleration, normally in a high gear at low speed. It's not a grinding noise (quite hard to describe, sorry), but more of a rattling noise, similar to a loose exhaust manifold heat shield I guess, but it's not a vibrating noise!

For example, accelerating at 2,500 rpm in sixth gear, this noise can be heard. I would say it's more of a scraping noise, definately coming from the engine. It's quite hard to trace, as when the car is revved at standstill or on idle, the noise cannot be heard. I have also tried driving the car at a high speed in low gear, and there is no noise. For example, driving at 60mph in 3rd gear - it sound perfecly healthy - OK it's revving quite high, but there are no nasty noises.

So basically what I am hearing is a scraping noise coming from the engine when accelerating in a high gear. The only real way to describe it is imagining a loose heatshield, that is ever so slightly touching the exhaust!

Any ideas anyone? Are the manifold shields prone to coming loose on these. Haven't had a real chance to look yet, but will have a look sometime this week!

Any help appreciated as always!
Cheers,
Tony.
 
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#3 ·
Thanks mate, but mine sounds perfect at standstill. I have had a cambelt fitted around 5,000 miles ago, complete with new tensioners and water pump etc. I am wondering if it's coming from the belt area - if so, what would it be?

Worth checking what you suggested though, thanks for that! Is it under the heatshield then on the manifold?
 
#8 ·
can you point to where the noise is coming from? (ie. front left, front centre, front right?)

I had a rattle coming from the front left. It sounded the same as if you were kicking an alluminium can on concrete.

It turned out to be a ball joint. There were no steering issues until a few weeks after the rattle began.

Regards,

diego.

PS. Forgot to mention that the noise only happened at certain revs. weird.
 
#9 ·
i had a tapping clacking noise from the front bank of my v6 drove me crazy for months, turned out being a loose cam cap, the one where the lock tool goes, dealer had stripped the nuts from over tighetening and the cam and cap was rattling like crazy, a few nuts later and prob was all solved
 
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