Cambelt Question

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trogedon, Feb 8, 9:13am
While on the subject of cambelts. I need to replace the belt in our Libero (I did it at about 110k kms and its now on 202k kms). I only did the belt (not waterpump, tensioner etc) last time. I was thinking I'd need to do the lot now. Should I or shouldn't I? Some of you were saying you'd know when a waterpump was had it etc and could last say 400k kms

goldilocks64, Feb 8, 9:17am
do it all cheaper than a dead engine if the tentioner craps out

franc123, Feb 8, 9:17am
They are lying. If you want to rely on a 20 odd yo pump with 20 odd yo bearing and seals thats rotated hundreds of millions of times in near boiling liquid under pressure and you consider it should be left there for even more service then leave it there. Its your motor.

ladatrouble, Feb 8, 9:43am
If the waterpump can be done without touching the cambelt and you are doing the job yourself. then your decision. If it means pulling the cambelt off to do the waterpump, and you are doing the job yourself. then your decision again. Just depends on how much work you are prepared to put into your car.

mack77, Feb 8, 9:54am
Definitely do them both every time you replace the cambelt, it's what's called preventative maintenance. I think that the only person that would disagree with my opinion is someone that is desperately short of money.

mechnificent, Feb 8, 6:42pm
At 200Km I'd do it. In my experience you'd probably be lucky to get a third belt's life out of the pump. I'm confident they do over 200, some where near 250 thou a few seem to start to fail in my experience, by 350 I suspect most will have failed. depends on car and maintainence and usage of course.

Changing them with every belt just as a matter of policy is a foolishness that costs the customer and doesn't give any real assurance anyway. And fitting a water pump, including refitting a second hand belt the mileage of which we know. is something we are meant to be trained to do. Then. we are meant to be trained to ascertain the condition of parts. And use our discretion.

The using of our discression. that is the professional part of any profession. it's easy to write legal pleadings or tightem muts and bolts. It's knowing what to do, and when, and why that is the reason we have professional people that are immersed in all the aspects and ramifications of the work, so they can make intelligent, well informed decisions that the customer would never have the knowledge or experience to do.

These days unfortunatly, charging for your services is what is considered to be "in the profession".

charlie4561, Feb 8, 8:34pm
I think the advice on water pumps lasting over 200,000kms, definitely does not apply to a lot of Euros which have waterpumps with impellers made of plastic. These waterpumps regularly grenade long before 200K or even 100K. Always change your waterpump with the timing belt on a Euro!

mechnificent, Feb 8, 9:27pm
So when these plastic impellors give out, and stop pumping the water. is that not a matter of age ? And. does it "grenade" the whole motor ? Or just cause an overheating problem requiring a pump change ?

Are we treating a real problem, or just fear of the problem ?

charlie4561, Feb 8, 9:47pm
It just means overheating that requires a pump change. By "grenade" I was just meaning the waterpump, not the engine. I remember having to pick up bits of waterpump from all over the engine bay when one failed on my E36 BMW years ago anyway - grenade is too emotive a word really, but seems to an apt description as plastic bits flew everywhere.

thunderbolt, Feb 8, 9:51pm
Mechnificent, I have read your stance on preventative maintainance in a couple of threads now, and I don't think you are doing your customers any favours (despite the fact you save them a few bucks)
Joe public treats his car as an appliance. JP most likely wont notice the spike in temperature when the waterpump impellor falls off and will keep driving until the damage has been done.
And if this occurs 6 months after a timing belt replacement where the opportunity was there to replace items like this, are you going to cover the repair costs? Don't think so.
Your role is to provide repair and service to minimise the chance of an issue between service periods, to give your customer trouble free motoring. Your methods simply don't do that.

mechnificent, Feb 8, 9:58pm
Yeah I understood that it was only the impellor. My point was that the shaft still spins, the belt stays on, the belt job does not get destroyed.
It's not the end of the world, and it doesn't justify fitting new parts just as a matter of routine every time we do a belt job. not unless the job is a real bitch to do. which, to a competent mechanic. shouldn't be the case ever. not on most common cars.

mechnificent, Feb 8, 10:02pm
Actuall my methods do do that, and I do stand by my work, and judgment.

I'm self employed and have all regular customers, some of which I've been working for for near forty years, and some of which keep their cars for years. my reputation is very good. I've been told repeatedly, and by service managers and bosses that have employed dozens and hundreds of mechanics, that I'm the best mechanic they have ever known/had.

gmphil, Feb 8, 10:05pm
how often in well do u service that bike aye ?
willing to get mrs trogedon stranded ?
do the whole lot this time

charlie4561, Feb 8, 10:13pm
It certainly is not disastrous if you catch the overheat on time. Anyway I would tend to agree with you about not needing to always replace the pump for Japanese cars, but the water pumps on German cars are such junk that you might as well really.

mechnificent, Feb 8, 10:16pm
Discretion. that is what we get paid for. that is the mark of the professional.

thunderbolt, Feb 8, 10:28pm
You may have overlooked this question:
Joe public treats his car as an appliance. JP most likely wont notice the spike in temperature when the waterpump impellor falls off and will keep driving until the damage has been done.
And if this occurs 6 months after a timing belt replacement where the opportunity was there to replace items like this, are you going to cover the repair costs?

Maybe you are working on older cars and are yet to be swamped with poorly maintained Euros (and Jappas) imported from Japan and Singapore, but I see the results of your old school thinking far too often these days to buy into your methods.

mechnificent, Feb 8, 10:39pm
The scenario you describe has happened to me once if thirty-seven years of repairing cars. on a toyota, and it happened only about a month after the belt job, when the pump had tested as perfect. I suspect there was some catastrophic cause. Rust blob getting into the pump perhaps seizing it up. Some thing that my experience tells me could/might have happened even with a new pump fitted. I've seen that

thunderbolt, Feb 8, 10:52pm
Could have, but would have been less likely as a water pump replacement should be accompanied by a good cooling system flush. In fact I understand there is no warranty on waterpumps in some markets without proof of adequate cooling system cleaning.
The bearing in that waterpump (if cambelt driven) is no different to any other idler or mechanical tensioner in the system.
When you fit a new belt without replacing these components, you are asking an part that has done millions of revolutions to do the same amount again, but under higher tension levels and with old grease trying to lubricate it. You simply cant always get away with it.

mechnificent, Feb 8, 11:23pm
Yawn.

mantagsi, Feb 9, 1:23am
When I did the cambelt in my J30 Maxima I replaced the waterpump, tensioner, thermostat etc as well. Fact o' th' matter was that the parts were so cheap (name brand, bosch etc) that I couldn't justify trying to squeak another 100k out of the existing parts even though I knew the history of the car from brand new, the cooling system was in tip top shape etc etc. I am a sucker, but I'll pay an extra few bucks for the good old peace of mind.

bigfatmat1, Feb 9, 1:35am
people without cam belts dont change the pump every 60-100k or 5 years

dublo, Feb 9, 9:52am
Life is a bit easier with old cast-iron ohv engines: if you see the odd drop of coolant coming from the pump, loosen the fanbelt, whip off the pump (3 nuts) and fit a new or rebuilt one - a 10 or 15 minute job!

tamarillo, Feb 10, 3:26am
Agreed. Some cars need front engine apart to do water pump so best do it while cam belt done. If easy access leave well enough alone and wait till it starts being a problem then fix quickly.

mechnificent, Feb 10, 3:33am
That would be called using your discretion Tamarrillo. Then we just have to come to terms with "easy".

jmma, Jun 26, 6:45am
Do a head gasket, oh may as well replace all the valves while I'm here, they gonna wear out sometime (o:
I'm with you on this one mechnificent !