Why 12 month oil change on low use vehicle?

Nope. Start in garage, reverse out, stop to use keys to lock garage. Start, drive to post office to drop package off, stop. Start, drive to chemist to drop prescription in, stop. Start, drive to supermarket, stop. Start, drive to supermarket forecourt for fuel, stop. Start, drive back to chemist, stop. Start, drive home, stop. Unload car. Start, drive into garage, stop.

Total mileage = 8. Total starts = 8.

BTW, cam belt shock loadings occur whether the starts are with a warm or cold engine, and might in fact cause more wear during hot starts.

Even 10 a day would be more than I would consider average. Start car, drive to work, stop. Start car, drive home, stop. Two starts.

For the situation you are describing, a lot would depend if it was the sole family car, possibly doing longer runs at the weekend, or just a local runabout.

Indeed, but for those 20 starts, (s)he might have covered perhaps 200 miles. That's 1 start per 10 miles. versus 1 start for 1 mile for the granny.

Two of the three scenarios you have described show exactly why low mileage vehicles may well need more frequent cambelt changes.

Chris

If belt failure was occurring out of warranty but within the advised limits, you can bet your boots that lawsuits wouldn't be far behind. And the focus belt was time expired. 10 years and a few months > 10 years. QED. Also, if the belt had been changed at the proper time, the imminent failure of the tensioner would almost certainly have beeen spotted. Serves them right.

Steve

No they don't. Cambelts are recommended to be changed at certain time and mileage figures. If they were failing early as you and others claim, it would soon come to the attention of the manufacturers (and their lawyers) and the recommendations would be changed. If certain usage meant that more frequent changes were required, that would be stated, yet to the best of my knowledge it isn't. At least not such usage that would be specific to low-mileage granny.

Steve

Didn't seem to bother Vauxhall a few years ago, when they had belts frequently failing well before the stated interval. They just halved the recommended interval.

Of course, as every handbook I've read states that service intervals are only a guide, and that for usage such as frequent stop/starts, the intervals must be reduced, any lawsuit would have to try to prove that the vehicle hadn't been used outside normal parameters. An almost impossible task, obviously.

Assuming a petrol Focus, tensioner change with the belt is normal.

Chris

Yes they do. Choose not to acknowledge it if you like.

Some years ago, Ford introduced 100k/10 year intervals. Vauxhall responded with a new Astra with 72K intervals. Few ever got near that milage, so the interval was reduced to 36K. Is that not a case of belts failing earlier than the service interval?

"Severe duty conditions:

Short trips of less than 10 miles..."

Chris

Sorry, why would running an engine that's cold & stopping and starting not be more severe usage than Running it at a nice warm constant temperature aznd fairly constant speed? &, unlike you, I've done the engineering & looked at the oil analysis for engines that have done both. Light usage will make the cambelt last ages, but light usage isn't stop start motoring & short journeys, it's cruising down the motorway or holding a nice steady

And of the recommendations being changed. this is stioll nothing to do with granny.

Link?

Steve

You snipped what I was replying to.

You stated "If they were failing early...the recommendations would be changed".

My reply was to show you that cambelts *do* fail earlier than recommended, and manufacturers *do* change their recommendations.

WRT early failure on vehicles with non-standard usage such as frequent stop/starts, in spite of others with many combined years of experience in the motor trade telling you the same thing, you simply don't want to believe it.

If/when you become a low annual milage driver, it's your wallet...

What do you think this:

""

meant?

I don't have a link to the glove box of my car...

I'm sure this information would be available online, but if I went to the trouble of finding it, you would simply refute it on the basis that you can't believe what is written online.

Clearly this thread has drifted wildly OT; FWIW, I tend to support the idea that condensation on the inside of an unused engine would be unlikely to cause the sump to drop off. I think the poster's intention was slightly tongue-in-cheek.

The evidence freely available regarding early cambelt failure on short- journey vehicles is compellingly in favour of it being a cause however.

Chris

I knew there would be something we could agree on :-)

Steve

Ford did the same on belt drive Diesels. 60K in book that came with car. Colleague had his fail shortly after buying the car, 48k on the clock. Got to dealer and was told the was TSB stating 45K change. On going to collect it and being given a £750 invoice he was told 36K.

Has anyone tried to get TSB info from a UK dealer? They won't tell you. Unless they are using it avoid a claim, then they will wave it your face and say you should have known.

Four things can happen to a belt:- failure of the structural webbing through cyclic fatigue, tooth wear, chemical deterioration or indirectly through failure of other components.

You use the word "wear" for your scenario. This cannot be the case.

Not necessarily.

You've posted your usual pseudo techno-babble, but completely failed to provide *your* definition of "wear", making your post pretty much meaningless.

In the context of this thread, I've used it to mean a condition whereby the belt's life if shortened. How does that not meet the things you have described?

No; pretty likely however.

Chris

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "shazzbat" saying something like:

Hmm... I recall the early Escort 1.6D vans - very simple cambelt arrangement that endured much abuse and never broke. Just as well, as the company I worked for hardly ever serviced them. The 1.8D engine, otoh, the belts would break at 60K, give or take a couple of thousand. This was a courier company and the vans were in use almost round the clock, some of the 1.6Ds reaching 250K.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Duncan Wood" saying something like:

Five years or 60K miles for mine. Religiously, according to the manual. I'd expect a low mileage one to be done on a time basis. Gave me a bit of a shock when I inspected the old one - the belt was fine (I suspect the PO paid for a belt only), but the idlers and pump bearings were noisily knackered. Just in time, I think.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "shazzbat" saying something like:

I can see that happening when and if the oil is already contaminated by short runs. A nice cosy little evap/condensation cycle at the lower level. If there's no water contamination in the first place, it shouldn't occur like that.

Oh, silly me. I was under the misunderstanding that motor companies employ scientist and engineers. In future I shall have to bear in mind that they use witch doctors to cast spells and parts need to be replaced when the magic runs out.

I asked for something technical but you jumped in. I have no doubt that patterns of use have significant influence on patterns of wear but some things embedded in motoring lore have disseminated from half facts and Chinese whispers. Some things leap out as needing further examination - to discover whether it is just anecdotal or whether there is any solid basis.

I put the word "wear" next to the word "tooth"...

I'll make it simpler for you. If someone brings in a car for belt replacement at the allotted mileage, the teeth will show sign of wear. If someone else brings in a car at 4 years old that has only done 6K and is scared into spending £300 by a spanner wielder that the magic has run out, the teeth will probably not show any sign of wear.

Such things as "40K or 4 years" might have more credibility if was something like "40K or 6 years". Moderate usage is not "harmful" (by whatever definition you care to choose).

Cars are designed for roughly a 100K/10 year life. If a car only does 2K a year, the fact it might be scrapped 80K short of potential is not a disaster. Maintaining to book on the basis that it could reach 100K is costly and pointless.

In order to establish why something failed, it is first necessary to see how it failed.

It's not all about teeth wear, you know.

It's actually more likely that a little used car will throw the belt off due to the rubber going stiff.

The time limit is there for a reason - because rubber will harden and snap over time.

I'd prefer to change the belt at £300, rather than rebuild the engine at

Yup.

Chris

Err why? Average usage isn't 10k a year anymore.

That's dependent on the car.

Yup, although owning it on that basis would be rather more costly than using a taxi.

Wearing the teeth off is very rarely the actual failure mode of toothed belts,generally either they snap or stretch or the tensioner or driven components fail. In fact I don't think I've ever seen one do that in any application, automotive or otherwise.