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[I_want_an_Omega]

Ok, so we know that the belt/tensioner life is 40,000 miles or 4 years - whichever comes first.

I can understand why the mileage limit as that roughly equates to an amount of wear.

So, why is there a time limit as well? What is there in the belt/tensioners that is time critical and could decay to the point of causing a major failure? The 2 cambelts that I changed seemed to be in perfect condition and the tensioners/rollers felt as good as the brand new ones.

I'm thinking about cars that do low miles, why a 4 year limit and not 5 or 6?

I'm not condoning pushing ones luck - just curious as to what actually fails and why.

Thanks - Rob

[Kevin Wood]

The rubber belt can deteriorate with age and the tensioner bearings can dry out whether used or not.

The bearings normally feel fine when changed. The problem is, when they start to deteriorate, they go very quickly indeed.

[TheBoy]

From a manufacturer's point of view, a time limit has to be on the warranty anyway. Thats why everything has a time limit, as well as mileage.

In case of this, does the belt age? Grease in the bearings? Tensioner ages?

[Lazydocker]

The rubber belt can deteriorate with age and the tensioner bearings can dry out whether used or not.

The bearings normally feel fine when changed. The problem is, when they start to deteriorate, they go very quickly indeed.

Hardly surprising when you consider how fast they're spinning

[Andy B]

Vauxhall are just covering their backsides. It used to be 8 yrs/80 000 miles but had some tensioner failures so bottled it & halved the time/distance they should be changed.

[TheBoy]

Vauxhall are just covering their backsides. It used to be 8 yrs/80 000 miles but had some tensioner failures so bottled it & halved the time/distance they should be changed.

And increased it back to please fleet managers, suffered an unacceptable failure rate, and lowered it again.

So its a little more than arse covering, they've done it twice, and got bitten twice.  Its clear that if you ignore the 40k/4yr, the risks, as deemed by GM (who desperately want it to be 80k/8yr), are too high

[Lazydocker]

Vauxhall are just covering their backsides. It used to be 8 yrs/80 000 miles but had some tensioner failures so bottled it & halved the time/distance they should be changed.

Or realised that the revised interval was too long because of failures

You fancy trying your luck going 8 yrs/80k?

[I_want_an_Omega]

Fair enough - that all seems very sensible. Thankyou.

It's interesting that Vx started off with 80,000 miles and then dropped down to 40,000  - so it looked as if something in the grand plan of the design wasn't up to scratch. Any idea what it was?

IIRC there was talk of nylon pulleys desintegrating at the time - but our V6s dont have any do they?

Pal of mine runs a small garage, he recently showed me a Pug 306 engine whose cambelt was only a 1/4 inch wide! One very lucky owner.

[Kevin Wood]

IIRC Vauxhall tried the plastic tensioner route with the earlier C series engines and got burnt there too yet the Ford Zetec has them and the belt on those is pretty reliable at 100k/7 years, IIRC.

The bottom line is that different engines put these bearings through different levels of punishment as they run at different speeds, tensions and different levels of vibration being transmitted to them through both the mounting to the engine and the running of the belt.

As said, Vauxhall would have dearly loved to halve the frequency of this expensive maintenance task, and they tried twice, so the 40k/4 years rule has been tested well in real life and found to be appropriate.

[peteelite]

Lincs Robert

I understand the point of your post is not to try to take your cam belt change to 80K/4yrs,just questioning the thinking behind it,asking questions is a good thing (otherwise forums like this would not exist). but have a look at my post 1st March "24 bent valves"..this happened while my new cam belt kit was sitting on my workbench "waiting for the right moment to be fitted"..well that moment came and went.

Regards. 

[Marks DTM Calib]

The V6 never had plastic idlers.

The 4 pot Ecotec does, the early ones suffered failures due to the use of to much glass in the glass loaded nylon so they were brittle.

You will note that they are still plastic but the 'mix' has been changed.

[Elite Pete]

The owner of this one had a receipt for a cambelt change, look like the belt was the only thing they replaced.

[Abiton]

"Cam belt/tensioner life of 4 years. Why?"

Because they are/were a bit crap underengineered.

[Varche]

"Cam belt/tensioner life of 4 years. Why?"

Because they are/were a bit crap underengineered.

Can't argue with that. I think in this day and age the cam turning mechanism should last the life of the car. Very poor engineering I am afraid.

We had company Vectras a few years back. I asked a guy to go to a meeting in Cardiff in my place. His car was due 80,000 mile service that day. The cambelt gave up at 80,040 miles. Cost just over £1500 to fix.

[feeutfo]

I always assumed the grease in the bearings dried out after a certain time, usually there is grease evident escaping from the seals, and the bearings themselves only lasted so many revolutions....?

But until we can examine a failure who knows.