Loud engine "tapping" under acceleration!

[Chris_81]

I've just been driving on the motorway at about 80, when my car had a sudden slight loss of power and a loud tapping sound developed. At first it sounded as though it was coming from the exhaust, as the noise is only there under acceleration. If I very gently apply the accelerator the sound isn't there but anything more than that and the sound is! The car doesn't seem to be down on power or any loss of acceleration.

I got home and popped the bonnet and reved the engine, and the sound is coming from the engine itself! It is a loud tapping type sound and seems to be coming from the top of the engine. :S

My car is a 2002 172 on 78,000. the cam belt and aux belts were changed at 55,000 in October 2007 and I've recently had it serviced at the end of February this year.

Any help or suggestions would be appreciated.

Thanks,
Chris

 

[Chris_81]

Just to add, I've just found out this only happens when the engine is warm!??
Started it up to show to my brother and reved the engine and the noise wasn't there. Let it idle and warm up for a couple of minutes before revving it again and the noise came back. Sounds very "tappy" and the idle is quite "lumpy".

Can anyone help?

 

[Chrisjk]

Coil pack at a guess.

 

[Russ_16v]

depends if the tapping is a metallic noise, can you post a vid mate? its quite hard to diagnose it by a description

 

[Chris_81]

Here's a video of the engine problem. When idleing the engine sounds very "tappy". Under gradual acceleration the loud noise isn't there. But when I "blip" the throttle the engine makes a very worrying sound. As I let the engine settle back down, the idle is very "lumpy" and is almost cutting out before sorting itself out.

Sounds like a feckin diesel! HELP!!:S

 

[W111ALG]

Dephaser pulley is going going and gonna be gone if you don't get it changed quickly!

 

[Chris_81]

What happens when this goes?! Fooked engine!?

Cheers!

 

[W111ALG]

Its the pulley on the inlet camshaft £124 from Renault but cambelt needs to come off to change it so expensive job. Theres loads of threads on it if you search "dephaser" on the forum. I had the same noise (though no where near as bad) and changed it recently when I was doing my cambelt and it now sounds good as new! Think the noise is caused by the bearing in the pulley starting to fail. Yup fooked engine if it fails!

 

[Russ_16v]

agreed, sounds like the dephaser, wouldn't be driving that chap