PD130 - Damaged cambelt, engine ruined?

[PD130TDI]

I have a PD130 Audi A3, but I can't find any information on my specific problem on Audi websites. I know the PD130 is in various VAG cars and this is strictly an engine issue so if you could please shed any light I'd appreciate it.



I recently changed my cambelt, waterpump and tensioners etc. using all the locking tools about 1500 miles ago. VAG-COM said that the timing was absolutely spot on.



I recently developed a problem where if I change into neutral to coast to some lights the revs will just drop to 0 and the car will stall. The car then became very hard to start either hot or cold, it would take up to 10 seconds to finally get it going. When it was trying to start it would show 600rpm on the tachometer. I changed relay 109 to no effect. The lift pump also works absolutely fine.



The car then just died randomly again(I can't remember if I was in neutral). This time I couldn't start it at all. When I tried the cam doesn't move at all. When I tried to turn it over the tacho showed 200rpm, not the usual 600rpm.



I looked at the cambelt under the cover and it is damaged and frayed, but is still in one piece and is still tense.



Is this a clear cut cambelt failure even though its still tense?



Could it be that I've ruined the starter motor and the belt damage is a freak coincidence?



Is it possible that the belt has slipped a tooth hence the non-starting and cutting out?



Does the fact it was trying to start at 600rpm and now at 200rpm have any relevance?



I really need to get to the bottom of this before I spend more money on the car, I can't afford to shell out money to fix it if there's an underlying problem that will make it happen again.



I'd really appreciate any advice or information, thanks.

 

[Nath.]

If the cam doesn't move when you start it i would say that your cam, belt has (although tense) a number of adjacent teeth missing, these teeth will be in the area of the small bottom pulley. The bottom pulley is the one for the crank so i would guess that your crank is turning whilst your cam isn't. This will no doubt have caused bent valves, this will upset the compression and be causing (along with a partially discharged battery) the 200rpm starter speed.

THE REASON THE BELT WITH ADJACENT TEETH MISSING STOPS ON THE SMALL PULLEY IS BECAUSE THE SMALL PULLEY ONLY EVER CONTACTS THE BELT WITH SAY 10 TEETH, WHEREAS THE LARGE CAM PULLEY WILL CONTACT THE BELT WITH MORE LIKE 20 TEETH, IF YOU HAVE 5 TEETH MISSING ON THE BELT ALL TOGETHER IN A GROUP THE SMALL PULLEY WILL LOOSE GRIP ON THE BELT BEFORE THE LARGE PULLEY AS YOUR BELT LOOSES TEETH.

You either fitted the belt badly or you fitted a bad belt. Was it a genuine belt?

Sorry for caps.

 

[PD130TDI]

Thanks for the reply.

I guess I fitted the belt badly. It's the first cambelt I've done (and last after this I think).

Would a slipped belt because of missing teeth also cause the cutting out from higher RPMs when I'd change into neutral?

What's the worse case scenario with this? Is it bent valves at the very least?

Thanks again

 

[Seatmann]

Head off and new valves and followers maybe, you'll need to check the valve guides aren't damaged but it's doubtful, more likely just need valves. You have to be careful though because even if a valve looks staight, if it's hit the piston at all it could break later so I think I'd go for a full set of valves just to be sure.

 

[PD130TDI]

Thanks for your advice Seatmann.

Do you have any ideas on the cutting out when put into neutral? Would that fit in with messed up timing?

Thanks

 

[Seatmann]

I take it the car was running fine before the timing belt job? If so then I'd say everyhting's related to something going wrong with the belt job. Timing, compression etc, you could try plugging the car i for fault codes too incase there's something less obvious in the background but I think it's probably due to the belt being screwed.

 

[PD130TDI]

Before the TB job it was running fine. I'll scan it over the weekend, though I don't think they'll be any codes, no CEL came on when it failed.

It has been suggested that the cam itself has failed, apparently the PD130 and PD150 engine suffered from this?

Thanks

 

[Seatmann]

Yeh but they just cause rough running due to the lobes wearing down, if your cam isn't turning when you crank it's the belt for sure, head off job and new valves. To be honest though that's probably cheaper than a cam job.

 

[PD130TDI]

So new valves, head gasket and timing belt (including tensioners and waterpump) and I should have solved the problem?

I've had a quote of £600 for all this from a decent garage, although they're not VW specialists. I won't be attempting another TB job anytime soon after all this

The other option is a second hand engine for about £500 then £450 to fit it. Is that a more economical option do you think?

 

[cocadave]

Just for clarity, when you crank the engine over the cam doesn't turn?

 

[PD130TDI]

Correct. When I tried several times to start the engine, the cam didn't move one bit. The belt didn't move either I don't believe (though couldn't guarantee it)

Does this have any bearing on it?

 

[cocadave]

sounds as though Nath is spot on, either that or the belt has come loose, either way sounds like the valves and pistons are getting it on...

 

[Seatmann]

sounds like the valves and pistons are getting it on...

Lol dirty engine


Personally I'd go with fixing my engine rather than going down the new engine route unless I really had to, you just don't know what the score is with another engine and there's a good chance you'd have a number of teething problems due to so many things being disturbed. You could check wether it's cheaper to pick up a head though rather than change the valves.

 

[Muttley]

If the engine is turning over but the camshaft isn't moving then you've certainly damaged valves, probably pistons too. But you need to find out what caused the belt to strip teeth - I'd worry that the camshaft has seized somehow, which will need to be fixed before fitting a new belt.

If the car ran satisfactorily after you'd finished your diy cambelt change, I'd guess that you did it right. I think that whatever has gone wrong is unconnected with your work, but in jamming the camshaft has stripped the teeth off your new belt.

You need to get the head off, I'm afraid, and see what the damage is.