Why 12 month oil change on low use vehicle?

That sounds like the obvious age related failure mode.

Oh, I've seen that one, but that's not caused by wear on the teeth.

I changed a cambelt in a Scirocco I bought years ago: it was 7-8 years old, 55k miles. In thise days, VW didn't specify a change interval, and I remember having to take a grinder to the crank pulley bolts (they were allen head and rounded out). The belt was cracked though 50% of the thickness. Since then, I've made sure belt changes happen at least

Now we're getting somewhere. Chris Whelan might be helpful with the "something's broken, how do I fix it?" questions but he's rather awkward when it comes to underlying matters.

However, this leads to another question...

When Ford fit a belt they suggest it can last 10 years whereas VW reckon it's a bit manky after 4. Now, I can understand different engines having different mechanical loadings but if it's a chemistry issue, surely someone must be wrong?

Yes, but you seem to be speaking for yourself and I'm guess you're not someone that does an unusually low mileage.

"Duncan Wood" wrote

Good enough round numbers. If some people see 200K in 10 years, it's not compulsory.

There are plenty that prefer the convenience.

When I changed my Citroen BX (at recommended mileage) the corners were radiused compared to the new one. I'm not suggesting "wear" has to mean they were trapezoidal.or reduced in height.

Though bear in mind that the discussion is about the point of changing things at low mileage. I don't doubt that a mileage is specified for reason. It is when dire warnings are given about exceeding time limits where matters get horribly muddy.

Actually, the last 2 VWs I owned were on 8 year changes - but sensible people did it on 4-6 years, due to a few known issues of belts snapping early.

Same applies to the Ford 10-year change. You may be lucky - or you may be unlucky - but as it's only £200-ish for most belt changes with my local mechanic, I'd prefer not to take the gamble - and would do it on 5 years max.

I have several vehicles - some are changed on time, some on mileage.

My Ducati (bike), for example, is well under the mileage limit - but is coming up to the 2 year recommended change this spring.

So I read that you're suggesting that Ford are being optimistic. If we can assume that VW are pessimistic, then your rubber ageing mechanism has credence.

On top of the additional cyclic loading due to the higher revs, the power transfer is probably higher than directly proportional (might even approach a square).

The service manager of the local Ford dealership is a personal friend. (I went to school with him over 50 years ago!)

When my last Focus was about eight years old, I asked him if I should consider changing the cambelt. He said they had never seen a premature belt failure on a Focus, so I would be wasting my money. He also told me that tensioners on early models sometimes failed, but in every case the owner had agreed that it had got noisy before failure, so could be predicted.

When the belt was changed at 10 years, and around 96K miles, it was difficult to tell it apart from the replacement.

Chris

Have you ever analysed the value of your posts?

Chris

Well it's risk to benefit, if you think owning a car is worth spending that much on for the convenience then risking it dying altogether as you wanted to save 0.5% of the cost by doubling your cambelt changes seems mad. If you're just going to scrap it & buy another old wreck it makes perfect sense.

There are occasions when an exchange occurs when I indicate I should like to understand in greater depth. A reply is written but it does not scratch below the surface. Prompting causes offence. Knowledge is not increased.

In view of previous attempts, I quite deliberately went for "please be technical" straight off on this occasion. Even this didn't work. If you claim to know something, then expect your answers or reasoning to be challenged (particularly when it involves repetition of motoring lore). Questioning does not imply possession of and holding back contrary facts.

OK, I'll rephrase that.

Have you ever considered if any of your posts actually help any of the posters you are replying to?

I've looked back at some of your old responses, and when replying it seems to me that you only ever question what help others have attempted to provide, without adding any significant knowledge to the thread.

Might it not be a more appropriate use of this group, if faced with something you feel is not correct, to find an alternative answer elsewhere, then post that information?

That way, you would be increasing your knowledge and that of others, without appearing quite so rude.

If you genuinely require more in-depth knowledge, you need to look elsewhere; it's not what usenet is about.

For my part, I freely admit I don't have formal competencies in motor vehicle technology. However, in addition to an interest in cars going back over 50 years, I have a lot of free time to find and bookmark online resources, and access to things like Autodata and Ford TIS, and I also have friends and relatives who work in various aspects of the motor trade. (Some of whom I've pestered late at night in order to provide a quick response to someone with a broken car.)

I also have a genuine desire to help others, and in that respect I'm willing to bet that I've provided valid solutions to many more posters here than you ever have, or ever will.

Chris

That depends. If people accept what a poster provides at face value, then attempting to expand the answer only affects the poster.

To be precise, one previous occasion.

Let me remind you, yet again, that you responded to my "please be technical" request. In your second reply you could have remained factual or just said "I don't know" rather than muttering "your usual pseudo techno-babble".

It is not necessarily that. When someone posts an answer, it sometimes needs to be examined. So the first port of call is to try and prod the person that provided the answer to explain how their answer came into being.

As I said earlier, if the question is "it's broken, how do I fix it?", then no argument.