Disco 1 300 Tdi auto timing belt wandering problem

[mike123]

The timing belt is walking. At 255,000kms the timing belt was replaced. The old belt had exhibited walking to the point where it was wearing into the front timing belt cover (or the front cover may have been like that before - who knows as I'd only just bought the car then). At the same time all pulleys/gears were replaced along with the back timing belt cover and after much time/cost it was supposedly fixed. So I was expecting 80,000kms from it. However,10,000 kms later on 265,000kms at the rego inspection the mechanic noticed black rubber fluff somehow. Low and behold the timing belt is wandering again and wearing. The main pulley was already the upgraded one to stop the belt wandering.

So the timing belt is replaced again after only 10,000kms along with the two top pulleys (the ones that are the same as each other but installed back the front in one spot and the right way around in the other).

Interestingly from the fix the first time (at 255ks) the Disco was a little sluggish on take off but I put that down to not knowing how it was to suppose to perform as I'd not long owned the car. After the 265k fix it seems more responsive than before.

So the question I'm wondering is what could cause it to wander in that short time (6 months)? The first mechanic is a LR specialist, the 2nd mechanic handles LRs and a selection of European cars. The reason for going to the 2nd mechanic is he fixed an earlier unrelated problem at short notice and did a good job as well as being a lot closer to my work than the first mechanic.

Any clues appreciated as I don't want to be changing belts every 10,000kms.

thanks,
Mike

[Blknight.aus]

theres 3 kits available.

if you mix up the bits of the kit the alignment of the idler and the tensioner will be off.

the specific instructions for the kits state there is no longer any requirement to wind the engine over by hand and recheck the torques.

FAFF.

put a paint mark on the cam belt and the crank pully pull the glow plugs back the valves off and turn it over by hand till that thing has aligned again... is the belt perfectly aligned? NO... fix it.

you may also not have the IP installed correctly or the mounting plate bolts for the cam gear may not be incorrectly torqued up so its skewed

The front engine case may also not be correctly mounted, torqued down or damaged, if this is the case the idler, tensioner and the IP gear will not be in alignement with the crank and cam gears.

[mike123]

Dave,

Thanks for the advice. It sounds like there is plenty of room to get this wrong and it appears this is what has happened. I'll talk to the second mechanic on Monday and make sure he has done as you've recommended. I suppose the moral of the story is to do it yourself and you know that is it done right.

thanks,
Mike

[Blknight.aus]

theres plenty of scope for things you're not expecting to go wrong to go wrong.

lets be fair to your greaser he has to make a profit.

as Im pretty much not for profit (not where I'm aimed but thats where I'm at) I can spend my sweet time sinking into a problem to find a route cause for a one off. if it takes me 3 weeks to find a cause to a symptom Im not out of pocket and you're just down your car for 3 weeks. Imagine the end result of a proper paid for mechanic trying to pull that off and then stinging you the bill for everything involved..

[rick130]

I agree with Dave, and if I can add the main issue with these things is the belt tension.

Do not do it as tight as the manual says.

There was a revised tension released in a TSB, IIRC it was only 11Nm maximum. (I'll double check that)
[edit] yep, 11Nm maximum.

It appears that most problems were caused by the initially too high tension spec, even after the revised kits were released.

Also try and use the one piece bottom pulley (as supplied in Bearmach kits)
The factory pulley sports spot welded ears.
These have a habit of falling off, you can imagine the consequences of that.

[redrovertdi]

It might also be worthwhile dropping the sump to check the thrust washers, floating crank will chew out the belt-just a thought?
Richard