Probably wise to check the aux belt tensioner and idler.
I found on my 1998 V70 Tdi (mechanically the same engine as the 2.5D) that the tensioner pulley bearing had got a bit stiff and notchy feeling and the idler pulley wasn't far behind it. They should spin freely.
The aux belt tensioner and idler both use bog-standard industrial bearings sandwiched between a pair of flanges held together by rivets to form the pulleys and if you have the time and inclination, these bearings can be replaced by drilling out the rivets, separating the flange plates and prising out the old bearings then reassembling with new bearings.
I replaced the rivets with machine screws and Nyloc nuts. The bearings should be stuck in the flanges with a suitable threadlocking adhesive otherwise they can fret and wear their way through the flanges. Unhelpfully the bearings used in the tensioner and idler are different.
It's probably worth a good look at the state of the harmonic damper which forms the crankshaft pulley too.
On the plus side, the cambelt is very well protected on these engines so an aux belt failure is far less likely to be the catastrophic event it can be on the later D5 engine.
Assuming there's enough tension on the belt to allow sufficient power to be transmitted to the alternator, power steering pump and the A/C pump for them to operate normally, I'd have thought it unlikely that a problem with the tensioner would cause the problems you describe.
Is the problem intermittent or does it happen every time you hit the 65-70 mph speed range?
It would be interesting to monitor the battery voltage to see what happens to it when the red light comes on since this would provide some clue as to whether the alternator was still delivering current.
Martin,
1998 V70 Tdi auto.
|