Hey guys, had a look at the common faults thread but didn't notice anything.

On idle 600-700 revs there is a consistant knocking in the engine bay, i can hear it through the cabin but when i open the bonnet and stick my head in i can't really hear it,
It only has this knock when it is on idle, as soon as it goes above 1000 revs it completely dissapears.

I was thinking it could be the water pump or one of the pulleys could be loose under low revs?

Any other ideas or which do you think it could be?
02 Ralliart Manual.

Cheers guys, any help i will appreciate.

Could be anything.
Use a long screwdriver, put the metal end on the running engine near parts you suspect, and press the other end of the screwdriver to your ear. You will soon isolate the area of the noise.

Be careful putting the screwdriver tip near running bits!

You sure its not a low oil tapping noise?

i just changed the oil made no difference. ill try give a modified version of what you said madmax a go :)

Bottem end bearing. Same problem with my 3.5 ages ago

Often a big end sounding knock is the ps belt not tight enough, sound from pulley echo goes up the back of the bay and sounds like a big end. Mits did many warranty bottom end rebuilds for this reason, mainly is also heard when warm engine at idle

Thanks alot mal,

i have heard big end bearings that are ruined before, you can usually hear them when you back off the throttle, mine is silky smooth so i dont think that id the case. i will try tightening the belt tensioners

It is a fine line with these from being noisy to over tight, being a flat style belt they need to be very tight, nip them up a little and see if that changes anything and go from there.

Also remember that #6 cams and especially Ralliart / 380 cams can be also noisy in the valve train, will sound like a whole heap of little rattles which often get mistaken for big ends as well.

ah ok yeah, this has only happened recently but i will keep my mind open

Is the big end knock a major issue? My engine has had a knock for years and not gotten any worse. I pulled the belts off and its still there so its not the belts. I narrowed it down to one cylinder and it goes away when that cylinder has it's fuel or spark cut.

its not this is it ? http://www.youtube.com/watch?v=ULAvH4coY0I i had a tensioner go on my vrx

nah this is 100000x quieter and not as rapid.