Why 12 month oil change on low use vehicle?

"shazzbat" gurgled happily, sounding much like they were saying:

I'm not the one that's claiming that the crankcase breather into the airbox is somehow "not open to the atmosphere" when the engine isn't running.

Let's put it this way - it has been on every single airbox I've ever been into.

But I'm willing to be educated. Do, please, explain what engines you've been working on where it isn't - and how it's sealed off.

"shazzbat" gurgled happily, sounding much like they were saying:

Certainly not crankcase pressure, that's for sure.

Which is, of course, complete bollocks.

The breather is on the intake side of the butterfly - assuming there is one, of course, which there isn't in one hell of a lot of engines.

Oh, and I'd love to hear you explain how the engine runs at all if you think the air filter is any kind of effective barrier to airflow.

Sorry, but I think you are wrong here.

There is a wealth of anecdotal evidence of early cambelt failure available online and from the trade; in almost every case, the vehicle usage could well have been a factor.

Doing lots of short trips is *not* "light usage"! In fact, it's this type of use that carries the biggest penalty of wear. In the case of a cambelt, the strain on it during the period when it has to start turning the camshaft(s) is much greater than the running load.

It's not the oil companies who devise service schedules, it's the manufacturers, and as the majority of new car sales are effectively to accountants, it's in their interest to have the longest intervals commensurate with a satisfactory engine life. Remember too that the manufacturer gets little benefit from servicing; it's the franchised dealer who takes the bulk of the profit from that.

Let's face it, oil and filters are not are largest cost of vehicle ownership; from my POV I can't see why anyone who is capable of DIY-ing the job wouldn't stick to the service schedule.

Chris

I seem to recall attempting to explain that an engine at rest was not going to have an access to a sufficient amount of air to cause the ludicrously overexaggerated claim that sufficient amounts of condensation would cause the sump to drop off.

I'm not going to attempt to explain to you the difference between an engine which is running and one which is not, since getting past brrrm brrm is going to be wasted on you. Just try to accept that the sump won't drop off.

Steve

"shazzbat" gurgled happily, sounding much like they were saying:

Indeed. And it's your explanations which I'm trying to explore here, not that particular claim.

True. Your "explanations" would be drowned out by the massed laughter arising directly from them. Your "brrm brrm" noises will be considerably less amusing. And, probably, a lot more solidly based in reality.

Did you bother to read my reply to that specific suggestion? Clearly not.

Anecdotal evidence = pub talk = bollocks.

From the trade = scaremongering to drum up business. Of course they're not going to cut their own throats. You'll never hear a garage proprietor say "It'll be fine", they will always say "Better change it to be on the safe side".

You're an adman's dream. I bet you love those shiny graphics about cold engines and metals grinding together.

Steve

it must have been concidence that 2 litre pinto belts always failed on a cold start (hundreds that I have seen) I have just had to rebuild a focus engine because the belt tensioner failed: recommended is 10 years or 100,000 miles, this had done only 75,000 and was

"anecdotal evidence.....available online..."

I'm beginning to realise Adrian is right; you simply don't read what you are replying to. (This actually makes much of your replies bollocks...)

Incidentally:

a) It's irrelevant where something is discussed; it stands or falls on its merit.

b) I don't go to pubs.

Unlike you, I go into garages other than as a punter. Certainly here in the SE, they have no need to try to increase their trade; they are one of few businesses that actually seem to be benefiting from the recession, as folk keep older cars for longer, and are tending to shun main dealers.

What do you think the average customer would say if told their cambelt will be fine, only to have it break soon after? Any trade is going to play it safe, just to protect their reputation. In that respect, they are right to say "Better change it to be on the safe side".

I also have a stepson who worked for the AA, and saw more broken cambelts in a year than you'd think possible. He often told me that it was never the vehicles you would expect; they were often driven by older folk, and frequently low milers.

I doubt very much whether I am anyone's dream; nightmare, maybe ;-)

Chris

Same difference. :

Yes, if it's pub talk and it's bollocks, it's still bollocks when someone comes home from the pub and posts it online.

Me neither. And?

Stalking; something else you're not very good at.

Certainly here in

In that respect yes, but as you try to avoid, we both know that the garage proprietor will say the same even if he knows full well it was changed a couple of weeks ago.

I was self-employed doing 24-hour recovery for 17 years; my experience is rather different.

Steve

I didn't know pinto engines had a metal belt, thank you for enlightening me.

So it should have been changed at 10 years but wasn't, and failed afterwards, and you're saying it failed early?

Steve

"Duncan Wood" wrote

Why? Please be technnical.

As far as I know only VW specify a time interval; 4 years is nonsense, obviously.

That's Italian electronics for you :)

Pinto belt failure always occurred at cold start, so more cold starts equals heavier use. The Focus was very low mileage for age, once again lots of small usages with lots of cold starts. I have often seen a belt on that engine go to over 150 k without problems, yet on this one low usage wore things out faster.

As has been mentioned several times already, the greatest wear to a cam belt happens at the moment the engine starts cranking, and the camshaft has to be moved from rest. In fact, sometimes with a belt near the end of its life it will jump a tooth; it only ever happens at start-up.

Lots of short journeys means lots of extra starts...

AFAIK, every service schedule quotes x miles, or y years, whichever comes first.

Chris

I came across a very good example of the problem of low mileage belt failure: A Corsa 1.4 16v came to me with belt failure and all the valves bent. It had 30 something thousand miles showing and was 6 years old. Never had a belt from new. Recommended is 40k or 4 years, at 4 years old it had 17k showing. The cause of failure was the water pump bearings had gone, allowing a slack belt to slip teeth. I questioned Vauxhall on this and the top tech at the local place said he had seen it many times on corsa/astra used for short journeys/ irregular use, apparently the water pump bearings get damp and rust leading to premature failure, regular use stops this happening. He said it should have had belt kit and water pump at 17k. Which is rather expensive motoring afaics. Incidentally although the bearings had gone there was not a trace of water leakage, showing that the inner seal was still working, even though the outer one had gone missing along with all the balls.

So now you're saying that lots of people exceed the stated mileage by 50%? I'm not buying that any more than the "low mileage is heavy usage" claim. And the focus belt you referrred to was time expired.

Steve

Not necessarily. Typical grannny driving behaviour is one cold start, drive to the shops, park, one warm start, drive home. 2 starts, one of them cold.

Yummy mummy behaviour would be something like 2 school runs, 1 shopping trip, and maybe a journey in the evening to take little Johnny to scouts. Probably not more than 10 starts in the day.

Typical courier or rep driving may be to drive 100 miles or so 2 or more times in a day, but he will also visit several customers, stop for fuel, stop for lunch, stop in a layby to do paperwork and make phone calls,etc etc. Maybe 20 starts in the day.

Steve

One start per mile, maybe one per two miles if she lives away from the supermarket. Cambelt life limited by time. And the start on the way home probably isn't a warm start, either, as it'll often be more than an hour after she parks up. The car won't be serviced more than once a year, either.

One start per two miles on average. Cambelt life limited by time.

One start per twenty to fifty miles on average. Cambelt life limited by mileage. The vehicle will also normally be serviced more regularly, which should mean that the cambelt will be checked for wear, too.

belt failure often occurs after the car is out of warranty and so the makers are not interested. The focus belt was not really time expired and had not failed, the problem was that the tensioner had fallen apart (plastic roller)

I have seen several N reg mondeos with over 130k before belt replacement in the last couple of years, so they were well over time and mileage.

It is much cheaper, quicker and easier to replace a belt early rather than risk failure.