Timing Chain Tensioner

[Mark and Cath]

I am sick and tired of listening to the valve chain rattle on my Aygo, It is fine once warm but cold it is sounds like a diesel. it has done 140k and so it deserves some new shims.

My problem is I can't see how you retract the tensioner and get the locking pin in. I have seen the Autodata diagram that says you can but looking down the side of my engine I can't see how. Does anyone have a photo of the tensioner with the engine out or can anyone offer any ideas?

Thanks all.

[Devon Aygo]

I'm assuming you have a 1.0 petrol and not the diesel, if so then there are no "shims" the hydraulic tappets are all individually sized instead, also a cold start rattle is more likely to be piston slap, a more common fault requiring modified : block, pistons & rings. I have never seen an Aygo with rattly tappets yet but have replaced a few blocks to cure the cold start rattles.

To lock the tensioner remove the inspection access plug in the timing cover and :

Insert a screwdriver from the plug hole and turn the stopper plate of the timing chain tensioner sub-assembly clockwise to release the lock, and keep it as it is.

Tech Tips

• The plunger of the timing chain tensioner sub-assembly is locked.

• If the stopper plate is locked firmly, slightly turn the hexagonal portion of the camshaft assembly to the right and left.

[Mark and Cath]

Thanks for the reply.

That is cause for concern that it might be more serious. I will drop the cam cover off and check the clearances cold. If they are OK then it looks a simple swap so I think I will change the engine. After all it is on 140k and that is a fair innings for a tiny engine.

[Devon Aygo]

Official measurements on a cold engine

Intake 0.145 to 0.235 mm (0.00571 to 0.00925 in.)

Exhaust 0.275 to 0.365 mm (0.01083 to 0.01437 in.)