Cambelt problems on Golf
Discussion
I've never done a cambelt change before but I thought I'd give it a go on my 1994 MK3 Golf Driver (1.8 8V SPI petrol, code ABS, power steering, no air con). However.....
Actually everything went well except for the first time I think I got the intermediate shaft one tooth out so it ran badly. I re-did the job and engine ran fine, except for a 'whirring' noise. I've traced this to the cambelt rubbing on the alternator pulley that bolts onto the crankshaft sprocket. I've tried another new belt and have also changed the tensioner, no joy. I've turned the engine without the alternator pulley attached and found the belt moves right up to, and past, the edge of the crankshaft sprocket so about 2 mm of the belt is sticking out - hence when the pulley is in place it is rubbing on it. I did not undo any of the crankshaft, camshaft or intermediate shaft sprockets so I can't understand why this is happening. I've even fitted the original belt back on and this is still happening. HELP!
Any ideas much appreciated, my pregnant wife is not enjoying the walk to the station and getting the train to work.
Cheers,
Doug
Actually everything went well except for the first time I think I got the intermediate shaft one tooth out so it ran badly. I re-did the job and engine ran fine, except for a 'whirring' noise. I've traced this to the cambelt rubbing on the alternator pulley that bolts onto the crankshaft sprocket. I've tried another new belt and have also changed the tensioner, no joy. I've turned the engine without the alternator pulley attached and found the belt moves right up to, and past, the edge of the crankshaft sprocket so about 2 mm of the belt is sticking out - hence when the pulley is in place it is rubbing on it. I did not undo any of the crankshaft, camshaft or intermediate shaft sprockets so I can't understand why this is happening. I've even fitted the original belt back on and this is still happening. HELP!
Any ideas much appreciated, my pregnant wife is not enjoying the walk to the station and getting the train to work.
Cheers,
Doug
I've come across this with the 2.5TDI engines as fitted to the Audi A6 and some Volvos. Alledgedly, there is some wear or missalignment caused by one of the pulleys. It is probably the crankshaft pulley which is throwing it out, but check them all. It may be wise first of all to ensure there is not incorrect seating of the tensioner pulley. Remove this and clean it and the seating surface, and refit.
Failing that, I'd go for the crank pulley itself. This is the one which sets the path of the belt. The other pulleys allow the belt to float and should not really influence the path of the belt- unless one is not fitted squarely. Good luck!
Failing that, I'd go for the crank pulley itself. This is the one which sets the path of the belt. The other pulleys allow the belt to float and should not really influence the path of the belt- unless one is not fitted squarely. Good luck!
Alfa Mad said:
I've come across this with the 2.5TDI engines as fitted to the Audi A6 and some Volvos. Alledgedly, there is some wear or missalignment caused by one of the pulleys. It is probably the crankshaft pulley which is throwing it out, but check them all. It may be wise first of all to ensure there is not incorrect seating of the tensioner pulley. Remove this and clean it and the seating surface, and refit.
Failing that, I'd go for the crank pulley itself. This is the one which sets the path of the belt. The other pulleys allow the belt to float and should not really influence the path of the belt- unless one is not fitted squarely. Good luck!
One comment on this based on my experience of Mk. 2 Golf engines - the tensioner pulley has lips on it so does not allow the belt to float. Don't know if this is the case for a Mk. 3, but if so then it re-inforces Alfa Mad's suggestion to check the seating of the tensioner.
Failing that, and if all the sprockets are in the right place, then the only other explanation that I can think of is a worn sprocket that is slightly conical and forces the belt to shift.
Hope you can get it sorted.
dougisaacs said:
I've never done a cambelt change before but I thought I'd give it a go on my 1994 MK3 Golf Driver (1.8 8V SPI petrol, code ABS, power steering, no air con).
Thats exactly the same as my car!! -not that that'll help you much
However, I have done the cam belt on mine (at the same time as head gasket), no prob's.
You problem does sound like one of the pulleys is not alined right, and as the tensioner is the only one you have had slack, it points to this.
Make sure that the bearings in the pulley are ok, and that the bolts that hold it on look like they are centred in the holes that mount the pulley and nothing looks mangled or deformed, otherwise it could be holding the pulley at an angle, hence the belt moves across it.
Pete
Thanks for your suggestions guys, I have already replaced the tensioner when I first got the problem and there is only one nut and stud holding it on so I don't think this is it, but I'll have a look.
Nel is right and there are lips on the tensioner although there is enough room for a small amount of lateral movement of the belt as it runs over it.
If it is the crankshaft sprocket i can't understand why as I haven't removed it?!
Nel is right and there are lips on the tensioner although there is enough room for a small amount of lateral movement of the belt as it runs over it.
If it is the crankshaft sprocket i can't understand why as I haven't removed it?!
Are all the sprockets nice and clean?
Are you putting the timing belt on in the right orientation? They have an arrow to mark rotation direction.
Other than these silly questions I'm at a loss - the only other explanation is sprocket wear as stated earlier. Failing all else, put it together with the belt rubbing and drive it to a friendly mechanic who can suss it out.
Are you putting the timing belt on in the right orientation? They have an arrow to mark rotation direction.
Other than these silly questions I'm at a loss - the only other explanation is sprocket wear as stated earlier. Failing all else, put it together with the belt rubbing and drive it to a friendly mechanic who can suss it out.
I've played with the tension and no joy. With the crankshaft sprocket itself, it is wide enough to allow some lateral movement, on one side of to is the engine block, the other the alternator belt pulley and this is what it is rubbing on!
The only explanation I can come up with is that while undoing/doing up the bolts for the alternator belt pulley from/onto the crankshaft sprocket I have managed to somehow damage the sprocket itself so it does not run true, but i can't quite see how this could be done to a solid metal sprocket which is presumabley bolted very tightly to a very solid crankshaft???
The only explanation I can come up with is that while undoing/doing up the bolts for the alternator belt pulley from/onto the crankshaft sprocket I have managed to somehow damage the sprocket itself so it does not run true, but i can't quite see how this could be done to a solid metal sprocket which is presumabley bolted very tightly to a very solid crankshaft???
dougisaacs said:
I've played with the tension and no joy. With the crankshaft sprocket itself, it is wide enough to allow some lateral movement, on one side of to is the engine block, the other the alternator belt pulley and this is what it is rubbing on!
The only explanation I can come up with is that while undoing/doing up the bolts for the alternator belt pulley from/onto the crankshaft sprocket I have managed to somehow damage the sprocket itself so it does not run true, but i can't quite see how this could be done to a solid metal sprocket which is presumabley bolted very tightly to a very solid crankshaft???
Agreed - hard to believe that you could put the crank sprocket out of true that easily. How did you immobilise the crank when undoing the crankshaft pulley bolts? You didn't jam a srewdriver against the crank sprocket I hope? If so then just maybe you have managed to damage the sprocket, though it seems unlikely. Problem is that I can't see any other explanation...
When you fit the belt, does it seat in the correct position on the crank sprocket and only move forward to touch the pulley when you turn the engine over?
Have you looked (with a mirror) into the housing around the crank sprocket to mverify that there are no obstructions/dirt in there?
Sorry, only questions, but am stumped...
Thanks for more help. I didn't use the aforementioned screw dirver method, I put the car in gear and got the wife to push on the brakes and used the resistance of the crankshaft itself.
Yes the belt does seat properly at first and takes a good few revolutions of the engine before it moves across to starting touching the alternator belt pulley.
I haven't had really close inspection of the crank sprocket so I will do, only problem is with the weather and dark nights, and an impeding holiday it may be week or so til I get the chance.
thanks again for the help, any ideas appreciated.
Yes the belt does seat properly at first and takes a good few revolutions of the engine before it moves across to starting touching the alternator belt pulley.
I haven't had really close inspection of the crank sprocket so I will do, only problem is with the weather and dark nights, and an impeding holiday it may be week or so til I get the chance.
thanks again for the help, any ideas appreciated.
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