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Thanks for the reply.
I take it the poly v belt would be the one that drives the alternator, coolant pump, air con etc? I'm not sure about that but I'm pretty certain the tensioner was replaced. I'll ask tomorrow.
I had the cambelt changed at 63k, which I know is well below the Ford recommended interval but at the time I was thinking of selling it and wanted to advertise it as having had that work done. Its now done about 73k.
I've squirted just about everything under the sun on the belt and its made no difference, so I was already angling towards the diagnosis of a pulley bearing. As said above, I'll be taking it to my friendly local garage for a further check.
I do tend to be quite sensitive to changes in the sound of a car engine, which is clearly an advantage if you're good at quickly and accurately diagnosing unusual noises and working what's wrong. Trouble is I'm not, and when I notice something that sounds different to the norm my mind works overtime thinking of the worst possible scenario; and of course the immediate go-to source of information which is the internet can easily lead you down the wrong path. Yesterday I was convinced that my fuel pump was on the way out because the fuel line sounded a bit more "hissy" than usual. Might simply have been because we were stuck in traffic on a hot day for a long period, which is quite unusual for this car.
I've already told my missus that if she catches me looking under the car for oil leaks, something I've been doing a lot of just lately (after finding out that a driveshaft oil seal was leaking and having it replaced three times ) she must gently nudge me in the head with her foot to discourage me from doing it.
Edited by argybargy on 07/08/2016 at 12:29
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Squirting anything on a rubber belt is a totally stupid thing to do. Wd40 is a lubricant, for christ sake. Exactly what you dont want on something transmitting power by friction.
You will have contaminated all your pulleys, and the belt will probably have a much shorter life.
WD40 is only useful for door hinges and its pretty useless at that. Its basically cod liver oil.
Get yourself a loud radio in the car.....
Edited by brum on 07/08/2016 at 13:12
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None of the belt manufacturers would advocate using anything on the belts. The effects of brake cleaner on a rubber or neoprene based belt is certainly not going to have any positive effect.
If the serpentine belt is noisy it probably needs replacing.
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Thanks for the reply.
I take it the poly v belt would be the one that drives the alternator, coolant pump, air con etc?
Yes, and it's as tough as old boots, as is the cambelt. It'll take more than a squirt of WD40, or anything else for that matter, to compromise their longevity, especially if you've washed it off. I fail to understand 'contamination of pulleys'. It would usually have been replaced while doing the cambelt, but quite reasonably might not have been at such a young age and low mileage.
Yesterday I was convinced that my fuel pump was on the way out because the fuel line sounded a bit more "hissy" than usual.
Our Focus is 7yrs older than yours, and for the first time stranded us earlier this year, all for want of a spare fuse for the fuel pump. When it's failing, it apparently blows its fuse as a warning on start-up. I don't know about your model, but I suggest you carry a spare 20amp fuse to get you home if the 15amp blows and it suddenly fails to start. This could happen tomorrow, or in 7yrs time, or never.
I've already told my missus that if she catches me looking under the car for oil leaks, something I've been doing a lot of just lately (after finding out that a driveshaft oil seal was leaking and having it replaced three times ) she must gently nudge me in the head with her foot to discourage me from doing it.
Good advice.
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The poly-vee belt may not have a tensioner.Many of the later Fords have a "stretchy" belt.
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Thanks for the reply.
I take it the poly v belt would be the one that drives the alternator, coolant pump, air con etc?
Yes, and it's as tough as old boots, as is the cambelt. It'll take more than a squirt of WD40, or anything else for that matter, to compromise their longevity, especially if you've washed it off. I fail to understand 'contamination of pulleys'.
Rather than trying to argue with JohnF how about we listen to some professional advice. Run the video here
www.gates.com/programs-and-promotions/auto-blog/he...e
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Ran it. Wasted 5mins of my life. Drones on interminably (like most US videos do) about 'misalignment' - an unlikely occurence in a modern mass produced engine, I would think. Perhaps the 'professionals' here can advise on how misalignment might occur, how common it might be, how to measure it and how to correct it on Ford Focus pulley wheels. I shall continue the occasional use of my belt dressing, which has worked for me so far - I have never ever changed a cam, fan or poly-v belt unless a driven component (e.g. water pump) has required attention.
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If any type of belt dressing was beneficial manufacturers would specify it in their service schedules and charge an exorbitant sum for the work. None specify it as far as I am aware.
If dealers thought they could get away with it they would try and add it into a service just like they do with injector, oil and fuel treatment, snake oils one and all. They would also charge a huge sum foir their kind use of more snake oil.
But the only advuice I have ever seen is if a belt becomes contaminated replace it iommediately. By spraying on the belt dressing you have contaminated it so for your own and any buyers sake replace it now.
Belts are cheap, engines are not.
Are you feeling lucky?
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If dealers thought they could get away with it they would try and add it into a service just like they do with injector, oil and fuel treatment, snake oils one and all. They would also charge a huge sum foir their kind use of more snake oil.
No they wouldn't, because they would prefer to have early failure of replaceable components. That is why during a garage so-called 'service', windscreen wipers are not cleaned, brake and petrol lines are not greased, rusty areas are not treated, brake discs are not de-rusted, springs are not cleaned and lightly oiled, dirty engine oil is not allowed to drain for long......and belts are not inspected, cleaned and dressed.
Are you feeling lucky?
Not lucky, but a certain amount of satisfaction that over several decades my cars and their components have lasted so long without expensive mishap - and with none of the problems that I so often read about on this and other sites which sometimes occur after (usually) well made machinery has been unnecessarily and inexpertly disturbed.
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As a Professioanal automotive Engineer with over30 years experience I agree with Skidpan.
I had proffesional contact with Gates Engineers in the mid noughties. Their advice? Do not spray anything on any rubber belts. If they receive a belt back with a warranty claim they will test it for any kind of chemical contamination and will reject the claim if any is found. Any contaminated belt should be replaced forthwith.
There's a reason Dealers don't try to "upsell" these products. They've been caught out before and it's cost them dear.
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Thanks for all the advice; conflicting though it might be.
I was hoping to get the mechanic to look at the situation again today, but he ain't available so it'll be tomorrow. I'm thinking the noise is almost definitely a pulley rather than a belt, because nothing I've put on the belt (and yes, I've put on quite a lot) has made any difference to the noise. Given the nature of the sound (a whoop rather than a squeal) I think that in my heart of hearts I probably knew already that no spray would make any difference, but I followed the instructions given by the mechanic to be sure.
One aspect of the above conversation does confuse me, being that brake cleaner is detrimental to a belt. I'm happy to accept that, but for me it poses a question.
You spray this stuff on your brakes to clean up the components, and amongst those components are various rubber gaiters and caps. Why then do those rubber bits not deteriorate from the effects of the spray, whereas a belt will do so?
I guess the answer is going to be something along the lines of "because a belt is under considerably more stress than a gaiter which just sits there doing nowt except covering something up", but I'd still be interested to know.
Edited by argybargy on 08/08/2016 at 16:37
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One aspect of the above conversation does confuse me, being that brake cleaner is detrimental to a belt. I'm happy to accept that, but for me it poses a question.
You spray this stuff on your brakes to clean up the components, and amongst those components are various rubber gaiters and caps. Why then do those rubber bits not deteriorate from the effects of the spray, whereas a belt will do so?
Good for you. All progress is made by questioning the dogma of doom-mongers. I too would like to see scientific evidence to support this assertion, which I do not accept.
Brake fluid, unless it's the rarely used DoT 5, is merely glycol ether and is deliberately made to be non-corrosive, otherwise all the flexible seals in a braking system would rapidly deteriorate as you rightly infer. In my view it is highly unlikely to have a significant deleterious effect on either a modern good quality belt or the contact surface of a pulley.
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One aspect of the above conversation does confuse me, being that brake cleaner is detrimental to a belt. I'm happy to accept that, but for me it poses a question.
You spray this stuff on your brakes to clean up the components, and amongst those components are various rubber gaiters and caps. Why then do those rubber bits not deteriorate from the effects of the spray, whereas a belt will do so?
Good for you. All progress is made by questioning the dogma of doom-mongers. I too would like to see scientific evidence to support this assertion, which I do not accept.
Brake fluid, unless it's the rarely used DoT 5, is merely glycol ether and is deliberately made to be non-corrosive, otherwise all the flexible seals in a braking system would rapidly deteriorate as you rightly infer. In my view it is highly unlikely to have a significant deleterious effect on either a modern good quality belt or the contact surface of a pulley.
In pedant mode, the query was about brake cleaner, not brake fluid. Brake cleaner is a fairly volatile hydrocarbon usually applied as aerosol spray.
Years back it was trichlorethylene before such things were banned.
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Yes, it was about brake cleaner, not fluid.
I did some Googling and, paraphrasing the consensus, it seems to be "don't do it, though if you do its unlikely to destroy your belts unless you do it on a regular basis." I did it once, and it does, I think, evaporate pretty rapidly. I rinsed the belts with warm soapy water afterwards, so if anyone is going to get away with committing such an outrage it'll probably be me. ;0)
However...I was idly browsing my Haynes this afternoon and as it happens, my belts are probably due for renewal anyhow, being beyond the stated 8 years of age renewal interval.
I went to a local garage and asked how much (because I know the fitting tools are not really worth buying just for one use) and the answer came back 30 quid including belts and fitting, which sounds pretty good to me.
So I'll probably get that done and consign these poor abused belts to the bin.
Edited by argybargy on 08/08/2016 at 19:49
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