Timing Chain tensioners - 150 engine W169

[rangerovering]

Hi Folks,

I have limited experience of what constitutes a healthy chain tensioner and what doesn't, should the plunger be smooth to push in and out when empty of oil? The one I have was replaced by MB 18months ago, we had a freezing night of -15C and when I came to start the car a day later it has a really bad tapping rattle. Codes were crank/cam out of correlation, also a dodgy cam sensor which I replaced - the noise is now still there but the fault now reads "crank/cam unrealistic positioning" or something to that effect, the car does start more easily with the new sensor though. The fear is that the chain is now very worn (146k) or that one of the plastic guides has broken and is causing chain slap.

First hope is that its the tensioner as its easy to replace! I took it out and it had resistance (ie holding onto oil), 4-5 compressions of the plunger and most of the oil was out and there is a notchy feel to it around mid travel although it is not seized.

2007 A150 manual.

Cheers

 

[rangerovering]

Hi Folks,

I have limited experience of what constitutes a healthy chain tensioner and what doesn't, should the plunger be smooth to push in and out when empty of oil? The one I have was replaced by MB 18months ago, we had a freezing night of -15C and when I came to start the car a day later it has a really bad tapping rattle. Codes were crank/cam out of correlation, also a dodgy cam sensor which I replaced - the noise is now still there but the fault now reads "crank/cam unrealistic positioning" or something to that effect, the car does start more easily with the new sensor though. The fear is that the chain is now very worn (146k) or that one of the plastic guides has broken and is causing chain slap.

First hope is that its the tensioner as its easy to replace! I took it out and it had resistance (ie holding onto oil), 4-5 compressions of the plunger and most of the oil was out and there is a notchy feel to it around mid travel although it is not seized.

2007 A150 manual.

Cheers

Bump

 

[rangerovering]

Well some progress I thought I would post up for anyone else working on a W169 as there is limited info going about. Took the power pack out with a mate on Saturday, 3 hours start to finish no fancy tools just 2 axle stands a trolley jack and an old supermarket skid frame with castors on - pretty straightforward and no scary bits.

Found 3 noisy idlers on the tensioner assembly, and also that the aux belt had been incorrectly fitted by a garage in the past . Rocker cover is off and so far I can see a fair bit of slack in the chain. Next step is to get the lower timing cover off.

Does anyone know the torque figure for the cap sprocket bolts?