engine knocking when warm(please help)

[j26]

my uncle bought a 172 that is knocking on the engine but only when warm, took for 5/10 minute test drive and no noise.
sounds like a dephaser pulley but heard these only do it when cold
He can leave the car running for 15/20 mins with no noise but drive around for a short journey (7/8 miles) the noise comes on and stays there, lift revs by 200 rpm when stationary and the noise seems to quiet down or go completly?
it is coming from top left hand side of the engine when looking down on the engine
dont want to spend £600/700 on belt kits and dephaser if not this!!! Belts were done 20000miles ago at 60000.

can anyone please help

thanks in advance

 

[MicKPM]

Who did the belts... any paperwork/waranty?

Deffo sounds like dephaser pulley and its an easy enough check: Camshaft endcaps out, top timing cover off, check for play in inlet cam.

Mick

 

[scotty2hotty81]

Dephaser pulley will be noisey when hot, not cold, raise revs noise will go.

 

[Andyrg@ ClioTurbo]

Dephaser pulley will be noisey when hot, not cold, raise revs noise will go.

Would agree here its when the oil gets hot. But hey!!! Its a renault!!

 

[Jamesb172]

My car is doing exactly then same thing sounds bang on from cold then after ten minutes when I pull up it sounds though it's knocking any ideas please

 

[Ol’ Tarby]

Dephaser pulley by the sounds of it