water pump failures

[turbineman]

in the current issue of magazine i read about electric water pumps,

am i right in thinking that mere water pump failure equals wrecked engine?

so it begs the question of upgrades,quite depressing really as this sounds like a job what needs doing.

i am not started any work yet but the more i read the longer the list,any views as to whether this is sensible or not,just that article seems to infer that NEW pumps are well cr^p is this the case or has anyone had good experience with replacement stag pumps orwas this guy (mag article) just the most unluckyman on the planet???

regards john

[Ian Durrant]

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Supposedly the water pump failure problem is over, it was a bad batch of incorrectly hardened pattern pump shafts. Yes if this gear fails it might be fairly catastophic.

However, we only have the suppliers word that the bad batch was just that. If your pump shaft is in good condition, does not look like a recent replacement and looks to have done some miles, then I wouldn't worry about it. Pump failure was not a common problem until non oem parts starting being available and the vast majority of Stag engines do not have a problem, providing the pump to cover clearance is carefully observed, the timing chains are correctly set (tension wise) when fitted.

However if your pump shaft gear is on the way out, try and source a used one in good condition *or* consider some kind of conversion.

As an aside, some people like to modify to EWP or an external pump because their is a slight flaw in the pump design in that it's position is high in the water circuit meaning even a small drop in coolant level can cause the pump to cavitate or even become devoid of coolant. *This is not an issue if you keep the coolant topped up and most of all have no leaks at all*

Hope that helps.

[Guest]

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Hiya John, back in the day, I used to know a good few VW mechanics, I'd always been a fan, still am, but they hated them, unreliable, badly made etc etc. most owners knew differently, but those guys only ever saw the broken ones, never the vast majority which were amazingly reliable and long lived. You could easily apply that philosophy to the Stag forum, we largely discuss problems, but NOBODY is going to suffer all of them - don't worry, Stag paranoia is a natural phenomenon that will go away in time, look after it and drive it, as often as poss Martin.

[turbineman]

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thanks for that, how is this checked i assume by stripping and looking

i know the parnoia thing too well and its growing, but will a healthy pump running ok lead to this failure or like other water pump failures lead to temp rise gasket failure etc or is it engine thrashed?

so is the conversions i have read about worthwhile or should the parnoia be given more FOOD to feed on?

regards john

[Peter Hills]

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John,

As far as the skew gears driving the water pupm are concerned, the guide as to serviceabilty is to look at the shape of the worn teeth. They should be 'flat-topped'. If they are worn until they are 'sharp' they are likely to fail soon. Ideally, the waer points - shown as bright areas where the teeth rub - should be well down from the 'flat top'.

If you put back well worn gears, the next thing you will encounter is the worn gears breaking up and the bits of broken teeth travelling through the engine oil supply. That means an engine-out rebuild - not less than £2000.00!

Peter

[Arbman Al]

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Hi John
There is always Stagdad's external water pump kit. Good reviews so far from those that have fitted it.
Rgds...Al

[turbineman]

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this would never be a job i would take on myself it sounds major compared to changing a belt driven pump,

just wondering if it is something that needs checked or leave well alone or is conversion the best route is this a service item that needs checked at intervals etc.

any idea conversion cost of belt driven pump?

[Arbman Al]

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You'll find the info on the for sale section of the forum.

[Sheepdip]

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Ian Durrant wrote:

Supposedly the water pump failure problem is over, it was a bad batch of incorrectly hardened pattern pump shafts. Yes if this gear fails it might be fairly catastophic.

Ian, the jury's still out on what causes this. I suffered a jackshaft seizure witha hardness tested (it had the stamp and certificate) pump and new jackshaft 3 years ago, itfailed after 1800 miles.Its still a debate whether its the gears failing ("experts" view) or tight chains (my view). Either way it was catastrophic and one reason why I'm going external. The other reason is that while the block has now been line bored with new bearing, I don't have confidence the water pump/gear will be alligned correctly now. The big benefit will be to get rid of that leaking pump!

That said my other engine runs a 6vane and I'm very happy with it! As you say if the bits look right, nice and oily and nothing amiss then refit.

Paul

[Ian Durrant]

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Ian, the jury's still out on what causes this.

Yes, that's partly why I said "supposedly" and why I mentioned chains and pump cover clearance.

[turbineman]

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so is the view that this is best done as modification i have looked at receipts and has
had a water pump fitted in 1989 12 vane.
just would like to hear your views.the thought of failure well really scares me:?.

[Ian Durrant]

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If you car doesn't overheat and has done reasonable mileage since 1989, personally I wouldn't bother modifying it.