Drive belt tensioner

[Lazzzydog]

The tester at the mot garage located the source of the rattle on the front of my Z’s engine. I thought it was the Vanos but luckily he found some slight movement between the arm and the body of the belt tensioner that was the cause. He gave it a squirt of oil that stopped the squeak but clearly that only masked the problem so I got a replacement from Euro Car Parts for £46 compared to £93 from BMW, both made by INA in Slovakia. The new one has a 16mm lug on the body to use for easing the tension when re fitting the belt but that is the only difference. It comes with the spring released which means that before fitting you have to grip the body in a vice and tension the spring with this lug until 2 holes align which you push a bar through to hold the arm in place to give access to the bottom bolt when fitting to the engine. Once fitted and the belt roughly in place but not over the alternator pulley you use this same lug to take the tension off the bar to allow the bar to be removed, the belt to be slipped over the alternator pulley and the tensioner released to take up the slack.

 

[Lazzzydog]

All very easy in theory but not so easy in practice on a prefacelift 2.8 as access is difficult. On later cars the radiator header tank is at the back of the engine bay but on mine it is at the front alongside the washer bottle and it is fixed to the fan cowling with a top and bottom hose running through the cowling. On later cars you undo the big nut holding the viscous fan and remove 2 push fit plastic fasteners at each end of the top of the fan cowl and then the fan and cowling lift up and off together giving enough room to do the job. Not possible on mine so I removed the air box which gave just enough room to force the fan off sideways without removing the cowling, otherwise I would have had to drain down the cooling system which I was keen to avoid. Fitting the tensioner is still akin to blind gynaecology but at least I don’t have the hassle of getting air out of the cooling system.

 

[Lazzzydog]

The heade tank that makes the cowling removal difficult.

 

[Lazzzydog]

Access with the air box removed and the cowling in place.

 

[Sean d]

To get the belt on just use a socket and bar on the pulley bolt, its really easy when you have access

 

[Z3I]

The belt tensioner is such a good idea. I removed my alternator a few weeks ago to replace it, and this feature made such an easy job of removal and reinstalling.

 

[Stevo7682]

What can I say easy on a 4 pot plenty room .

Although I feel your pain I do things like that every other day where you end up with the feeling of
Who on earth designed this and then who looked at it and went yeah that is a good idea