Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - anted

The alternator belt on my 130,000 mile 2.0 CR 2009 Passat failed the other week (at 3,500 revs in 3rd gear).

I am told by three independent mechanics (recovery vehicle man / VW main dealership / my usual mechanic) that fibres from the failed alternator belt then wound themselves around the bottom pulley, working their way behind the timing belt cover and causing the timing belt to slip.

On stripping the head down, my mechanic found the valves to be intact but all 16 rockers had bent to be almost straight instead of curved.

The engine was rebuilt today but none of the timings would align (sic, excuse my ignorance)...further investigation revealed that the lobes on both camshafts had been damaged by the slipped timing belt meaning that these camshafts will also have to be replaced. Apparently they are 'pressed on' rather than cast, meaning they are knocked out of alignment.

Total cost likely to be in region of £2k including labour.

The Cambelt was changed 1yr ago at 120,000 miles by VW a few months before I bought it...but I did not find out until investigating now that they did not change the water pump nor the auxiliary belt. I assumed that with main dealer history they would have replaced parts as necessary - to include the 120,000 mile old alternator belt and water pump.

Q has anyone else heard of this happening? I am shocked to say the least as I thought I was thoroughly maintaining my car.

Q is it usual for main dealerships not to change the alternator belt at the same time as the Cambelt?

I'm particularly disappointed as I saved up to buy the CR model that I knew would not then suffer from the expensive 'rounding off of the oil pump drive spindle' problem on previous models.

Would be great to have your advice, even if mainly to help others avoid this problem.


Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - Simon
From what you have said I guess that whoever paid for the cam belt to be done didn't want to spend money on having the water pump and the alternator belt changed too. There is no real right or wrong answer in my opinion. Yes it may be false economy, but why spend money on something that is working fine at the time.

In your case I think that you have just been unlucky, who could have predicted that the alternator belt was going to fail with such dramatic consequences? I'm afraid you will just have chalk it up to a bad experience, there is no real come back on anyone. Have you worked out why the alternator belt started to shred in the first place?
Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - Collos25

It may have been the other way round the alternator belt broke as a result of the cambelt slipping or he waterpump failing.When did you buy the car it sounds like the garage is trying to get money from you when in reality you should be claiming from them just a thought.

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - Rusty VW

I am finding VW dealers are charging for work not done.

look at

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - injection doc

Alternator belts fraying is common, and yes they have a very bad habit of finding their way into the cambelt dive pulley with horrendous concequences ! When this happens there really is no one to blame and its a horrendous misfortune.

The alternator belts even sometimes when renewed will fray especially if they have been driven through water causing excessive slip and burning.

The pressed camlobes slipping on the camshaft are deisgned that way to prevent further engine damage. In my current role I am seeing an alarming rate of cam lobe slippage.

As sad as it is when this happens there really is no one to blame ! certain cars do suffer from digesting fraying alternator belts more than others !

Just a though, have you contacted your insurance company to see whether they would cover the damage ? as it is damage ?

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - anted

Injection Doc - it is some comfort to hear that alternator belts can fray at any age for a variety of reasons. From what you have said the fact that both camshafts were damaged is small price to pay given that the valves and pistons are not damaged.

I have checked my Direct Line policy that states I am not covered for any mechanical, electrical or computer failure, breakdown or breakage but was worth checking.

Cheers, Anted

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - anted

Collos25, thanks for reply. I bought it over a year ago from independent (autotrader-sourced) garage with no guarantee, but full VW service history at 120,000 miles. I had it recovered to VW knowing the cambelt was done just before I bought it...they took the cambelt off, and fitted a new one before giving me a full diagnosis. Then told me it might need a new engine at £5950!! Exactly what I paid for the car, within a few pounds. My independent guy then looked at it but it was too late for him to see the shredded alternator belt and give his own full diagnosis. I was somewhat scared off by the main dealer 'new engine' conversation so decided to have VW take off the new cambelt (for free) and towed it to my independent garage who have done the rest of the work. I'm not expecting to succeed with a warranty claim but thanks for the thought.

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - anted

Thanks Simon.

Regarding the reason the alternator belt might have failed, about 3 weeks before it failed I had paid my local independent garage to do a full service - he used all genuine VW parts (no reason to doubt this, he is a one man band and showed me the purchase boxes) to include all new filters. The fuel filter is a cartridge type and he re-used the old seal on the outer casing that then leaked spraying diesel over the area including the alternator belt.

I discovered the fault after about 2 weeks/400 miles and he fitted an over-sized seal to the outer casing that stopped the fuel leak and cleaned up the area.

I was concerned that the diesel could have caused the belt to fail. After much discussion and diagnosis he persuaded me that the diesel would not have caused the belt to rot and fail for the reason that he has seen it happen many times before on high-mileage taxis and none of them has had an alternator belt failure within three weeks after diesel leak.

Anyone heard of the leaking fuel filter seal causing belt failure - or any other failures? Being about to spend £2k on the car I am keen to deal with any other small risk points while I can.

Thanks - anted

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - elekie&a/c doctor

Contamination by engine oil and especially diesel will most certainly cause a poly vee belt to disintegrate.On most VW models where the fuel filter housing is situated very close to the belt run,it is very important that the filter sealing rings create a total seal to prevent leakage.It is not an unknown problem on these.hth

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - 659FBE

This is indeed a sorry tale - with many facets to it.

1. Putting drive belts next to and below a fuel filter is just plain stupid. Thanks, VAG.

2. Euro legislation now forbids throwaway filter cans. This leads to contamination of fuel systems when the casings are opened, shortening their lives and also the increased likelihood of leaks. Thanks, Eurocrats.

3. Any service outlet working on these cars needs to be competent. Not renewing an old aux belt and assembling a filter housing with a leak (despite the unbelievably poor design) represents crass incompetence. Thanks, Service outlet.

Getting good service out of a modern diesel engine requires care, but it also requires attention to detail design and a good measure of common sense. This seems to be lacking in the case of the three organisations detailed above.


Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - anted

Hi elekie&a/c doctor & 659, thanks for helpful comments.

Would you have expected my independent guy to have tested the fuel filter seal for leaks after fitting it given he 'regularly sees the problem'? He described it as a fine mist. Would you guys run the engine for a period of time to test for a known fault like this before returning the car to a customer or doesn't it work like that in practice? I don't normally [need to] lift the bonnet more than every 2-3 weeks but became suspicious after about a week at the smell of diesel when walking past the car. I found diesel to have pooled in the top of the filter housing and on all components in the vicinity. I also couldn't understand why, when knowing there to be a problem with the thin filter seal he didn't fit the oversized rubber seal as a matter of course. Then, maybe none of this would have happened.

I noticed the tell-tale slight twitter of the alternator belt about a week after he had fitted the over-sized seal and cleaned off the area with some sort of solvent. I'm no mechanic but had an aux belt almost fail about 15 years ago and remembered the noise...but thought no more of it having convinced myself that it had just had a full service and forgot about it due to busy family life. Goes to show that instincts are often right! anted

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - 659FBE

I'm afraid that I would judge the failure of a service technician to check absolutely comprehensively for leaks following a filter change, to be a sign of utmost incompetence.

Fuel system leaks are intolerable and your service operator should know this. He should also know that diesel fuel leaks can be lethal to following traffic (motorcycles) and that the positioning of this filter on this vehicle above the belts, makes consequential damage highly likely in the event of such a leak.

Finally, having presumably worked on similar VAG vehicles, he will be fully aware of the stupid design of this filter housing - prone to both leaks from the cover and to fuel system contamination as the element is removed.


Edited by 659FBE on 17/03/2013 at 18:14

Passat 2009 CR Bluemotion2 - Aux belt-->Cambelt--> Rocker-->Camshaft failure - catchhster


Sorry for a really late response and I had a very simillar issue of alternator belt snapped and damaged the engine. I drive a same car same year and this happend exaclt like yours. the fuel filter was not fitted properly on servic and drove with fuel leak for exactly 400odd miles three days then i got it fixed. Exactly after two weeks of the service my alternator belt snapped. I think this is not just coincidece.

I am about to spend a lot of money now to fix the engine which i think it is not my fault

Would you like to talk to me about this? please contact me.




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