TDI 90 Cambelt Snapped

Halduck

Member
Just brought a second tdi 90 yesterday. Driving along the motorway hapily at 2000rpm when suddenly lost power. I immediately dipped the clutch. Stupidly i let go of the clutch to see if it was a momentary problem, still no power, so coasted up the motorway slip road with the engine having stopped itself.

Im guessing its fairly terminal as the ATL engine has interference valves?

Any advice eagerly received!!

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Just brought a second tdi 90 yesterday. Driving along the motorway hapily at 2000rpm when suddenly lost power. I immediately dipped the clutch. Stupidly i let go of the clutch to see if it was a momentary problem, still no power, so coasted up the motorway slip road with the engine having stopped itself.

Im guessing its fairly terminal as the ATL engine has interference valves?

Any advice eagerly received!!

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Bad luck is all I can say
Take the head off and have a look what damage has been done, Hopefully only a few bent valves
You will not have done it any more damage by letting the clutch out again, when the belt snaps the cam stops, if pistons are going to shack hands with valves then it will happen immediately, valves will be bent and/or holes punched in pistons crowns. Letting the clutch out and therefore spinning over the bottom of the engine will not do any more damage over and above the damage already done
 
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Oh my, sorry to read this.

If a private purchase and sold as seen you are indeed now in a world of pain.

Very, very unlucky, but yes, these things do happen.

Verify the cambelt failure by removing the cambelt cover.
Not much point in saying, but don't turn the engine over any further.
Unlikely, but possible, is that further cranking of the engine could snap a valve, drop it into the combustion chamber, and as the piston comes back up the broken internals could hole the piston.

Even if you undertake the repair yourself it's around £1000 to get it running again.

Sorry to read such bad news
Jeff
 
Maybe not. if the cam belt breaks the engine stops almost instantly with a loud clattery sound if its an interference engine. If non interference then it will continue to turn being driven by the road wheels.
Just loosing power could be a sign of many things. Dont go for the worst option.
Simon
 
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When I had a golf the timing belt went and it was a really loud bang ?

Hope it is not as serious as you think and good luck on the repairs
 
I concur with the optimists here - the first diagnostic would be to unclip the top of the cam belt cover and inspect whether the belt has actually gone. I must say, I've not heard of a TDi 90 snapping and my last 2 belts have been changed at around 75K miles (6 years) and 55k miles (7 years - dare not leave it any further) and in both cases, the belts removed were pretty much perfect condition.

You may well be lucky and have a lesser issue to deal with. Look on the positive side until you know the worst.
 
Don't lose heart here, similar thing happened to Project X before I bought her (as an eBay project). Marcus at WOM managed to fix her up for about half what was quoted above.

Have a read of the thread by clicking on the link below. I'm sure Rob or Marcus will be able to give more technical details.
 
Hi all, just got home after a long day! The cambelt has definitely gone. I noticed this morning that there was no cover on the cam belt which I thought was weird! When I pulled over, took the bonnet off and saw the cambelt in shreds wrapped around the pulley :(

I managed to get the AA to recover it 30 miles to my work rather than 8 miles to home as I have access to a full workshop with lifts and tools rather than nothing at home!

Hopefully it is fixable, as it would be a shame to break it if its too expensive to repair. The body work and running gear is in very good condition.

The cambelt was changed at 60k miles and 120k miles 2 years ago. It is currently at 133k miles. According to the service history it has been serviced 17 times since new in 2004.

I do have a bmw i3 battery pack sitting in my garage so maybe it could be converted into a 4wd rocket!

The car was sold as seen unfortunately so no redress :/

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I have an endoscope you can borrow if you want to take a look inside the cylinders without having to remove the head. I’m sure if you remove the injectors or the glow plugs it’ll fit down the opening, it’s only 9mm diameter
 
Hi all, just got home after a long day! The cambelt has definitely gone. I noticed this morning that there was no cover on the cam belt which I thought was weird! When I pulled over, took the bonnet off and saw the cambelt in shreds wrapped around the pulley :(

I managed to get the AA to recover it 30 miles to my work rather than 8 miles to home as I have access to a full workshop with lifts and tools rather than nothing at home!

Hopefully it is fixable, as it would be a shame to break it if its too expensive to repair. The body work and running gear is in very good condition.

The cambelt was changed at 60k miles and 120k miles 2 years ago. It is currently at 133k miles. According to the service history it has been serviced 17 times since new in 2004.

I do have a bmw i3 battery pack sitting in my garage so maybe it could be converted into a 4wd rocket!

The car was sold as seen unfortunately so no redress :/

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Strange that it has snapped after on 13k and 2 years of service , why would that be ? Poor quality belt or has the job not been done correctly ?
 
could be a bit of both, but I'd lay money on the job not being done right, unless a tensioner as failed or the water pump as seized
 
could be a bit of both, but I'd lay money on the job not being done right, unless a tensioner as failed or the water pump as seized

I'm not sure that our water pumps can seize in this way - the impeller is designed to spin on the shaft or break its fins before seizing and there's also a pressure bypass hole built in too. I'd imagine it's not been done correctly especially if the cover is missing entirely.
 
I was keeping my fingers crossed that something else was the cause, clearly not though.

2 years and 13K miles in I'd not expect this to be poor installation. The records are either false or I suspect that only the belt was replaced, and a tensioner or water pump bearing has colapsed, throwing the belt off the pulley teeth.

The only piece of reasonable news is you're obviously in the trade with access to lifts and tools, so a top end rebuild is likely labour-free for you.

I replaced my head gasket (TDi 75) as a preventative measure early last year and took the opportunity to refresh the cam-train (valves, lifters, springs, cam bearings, etc).
Seemed worth it for me as my car is a keeper.
Head skimmed was the only professional service I purchased, and all in my work cost just short of £1100 (so almost all of that was spent on parts).

If you'll keep the car once repaired I think it's false economy to teardown the top end and only replace the damaged parts (hopefully only valves), as the rest of the top end might as well refreshed while all the effort of a head-off and teardown is taking place.

Good luck whatever you choose to do.

Cheers
Jeff
 
Just got back from a week car testing abroad so this was the first chance I had to inspect the car. I thought I'd update this thread as I go along.Took the engine cover off and the belt is obviously shredded. The cam hasnt seized (asumming it is still in one peice) as I can turn the pulley +-10deg. I think that rules out the top end seizing and thowing off the belt as a result of that. Points me more in the direction of the tensioner not being replaced at the last cam belt change.

Have to leave work now, but more updates after I've spent some evenings next week going over it.

I'm currently leaning towards keeping the car longish term and making a positive out of a bad situation. So potentially porting/polishing the cylinder head or its replacement, egr valve body porting with egr delete, oversized valves, etc, etc.
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I replaced my AMF cambelt recently and noted the instructions have changed and specify new studs and a 'torque + angle' for tightening the nuts on the idler pulley mounting studs.
Previously the studs were not changed and only a torque figure specified for the new nuts.

There have been a few cases of the old studs not being replaced (may not be in the kit) but torque + angle used for the nuts resulting in the stud weakening and either necking off or the nut coming loose.

Just wondered if there are any indications of this mode of failure on your engine

Cheers Spike
 
Diagnosis: tensioner failed and threw off the cam belt. Either is wasnt replaced with the belt or as mentioned above the mounting bolts maybe weren't swapped!

I can wobble the tensioned around its failed/worn out innards.

Time to press on with assessing the damage!
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Those small "crescent" marks on the head look like it is where the contact was made with the cut outs in the piston crown.

It is not easy to see for sure but it looks like much less damage than I would have expected.

Replacing the valves that have hit and getting them all checked for straightness might be enough to get you back on the road.

The big end bearings might be worth replacing (or at least checking) because the engine coming to a mechanical halt like that might have caused some small damage to the shells.

But as I say, it is difficult to be conclusive. Fingers crossed for you though

Steve B
 
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