mr brightside
New member
The water pump for my 924s cost £350, presumably it was a porsche part but it was fitted by my indie. It is cast aluminium not plastic.
water pumps
- Thread starter mr brightside
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sawood12
New member
OK, ever since i've had my car it seems to be the case that you should change the waterpump every other timing belt change. Why? I've never known the waterpump to be a consumable item on any other car i've ever owned and it doesn't appear anywhere on any Porsche service schedule i've ever seen. Also both indies i tend to use (one was Porsche trained and worked for Porsche for years before going it alone) don't seem to think it is necessary, they just check the waterpump bearings for play when replacing the timing belt and if they feel good and run smooth then it should be good to go for another run. There isn't much to a waterpump so I can't see why it should deteriorate so quickly. Is this one of those urban myths, or is there a real reason necessitating such regular replacement interval? Has anyone suffered a waterpump failure as a result of not replacing the waterpump at a timing belt service they should have?
Scott, Very good Q - I have wondered the same. My suspicion is that there is quite a lot of "It's a Porsche" around, and therefore some kind of black magic is meant to overcome normal engineering principles. This black magic not only determines over-frequent water pump replacement, but also shrouds the process of changing a cam belt in mystery, amongst other things. If you come up with a more sensible answer, I'm all ears. Oli.
Diver944
Active member
I think it's one of those over cautious preventative things that sprung up after a lot of failures many years ago. Whether it's still worth doing is debateable as the pumps have obviously improved and do not fail as regularly ( I haven't heard of one for years [&:] ). However if a pump does seize then it will generally snap your belts and then you are looking at major engine damage. I'm always more than happy to pay £300 to prevent spending thousands or having to get rid of the car
sawood12
New member
Sorry to hear that David, must be frustrating, however I wouldn't classify a leak as a failed waterpump, unless it turns out to be a cracked housing or something of that nature. In fact replacing something frequently like that actually increases the chances of problems as you are disturbing seals and gaskets and there is always a risk of seals not seating properly and causing a leak, or being damaged upon re-assembly. Hope your leak is something as meanial as this rather than the pump itself - or worse. I suspect the waterpump in my car has never been changed. Though the timing belt replacement has never been missed, i've not seen an invoice for a waterpump in the whole history that came with the car, that dates back to when it was new. And when the timing belt was last changed by me at my specialists, he checked it out and it was declared perfectly serviceable as far as he could tell. Oh well, i've got a timing belt change due this year so i'll see what he says this time round.
944 man
Active member
Sort of: although it isnt unknown for the water pump to fail, seizing and stripping the drive belt. The reason that the 'advice' came about though, was due to the cost of the belts and rollers and the cost of dealer labour charges. If the water pump needs to be replaced between belt changes then the belts have to be replaced also (along with the rollers at most OPCs too...). Water pumps cost (then) about £200 (reduced to £100 at one point) so this made them a 'consumable' item when you compared this to the overall cost of the front engine service. Now a good independant will only replace whats neccessary and if a fault does develop with the pump then replacing it, along witht he belts, wont break the bank. Simon
sawood12
New member
Thanks for that Simon, i'd not heard that before, though most cars waterpumps are driven off the timing belt so still no reason for a 944 to be treated any differently - unless there is a recognised weakness in the waterpump and I certainly havn't heard that specifically, though it is implied by the regular replacement rule of thumb. I will probably err on the side of caution this time and replace the waterpump on the basis it looks like it hasn't been replaced before. One specialist did tell me that the thermostats on 944 turbo's (not sure about other models) seem to have quite a short life and mine has been replaced. I wonder if dodgy thermostats is what has caused incidents of waterpump siezures by allowing water temps to get too high and siezing pump shafts against bearings, or something along those lines.
stjohnsmythe
New member
I've just had the belts changed on my Lux by RPM. They have followed the same procedure as you stated above, checking the water pump bearings for play. I certainly haven't had any car in the past that 'has' to have regular water pump changes so can't see why the 944 would be any different.
craig2105
New member
Looking at my water pump a couple of days ago, there was the tiniest droplet of water on the housing that seemed to indicate a little bit of a leak. Will investigate further on Saturday when I can get the car on my mate's ramp at his garage, but what's the likely prognosis, chaps? Am I in for fitting a new pump do you think?
TTM
Well-known member
In one of their maintenance bulletins Porsche reckoned a "slight leak" is not a reason good enough to replace the water pump. The water pump on my turbo was original when replaced last year and at 170k miles it was leaking a bit but was otherwise working as it should. Here is how the place looked like when the pump/belts/gaskets were replaced ; green coolant can be seen on the upper edge of the balance shaft housing.
ChasR
New member
Some cars can be dodgy on waterpumps. My Peugeot 306 GTi-6 had a new waterpump fitted when I changed the cambelt, but the old one was perfectly fine. Conversely, a guy who had a new one put in 4 years ago had his corroding a little internally. On quite a few cars, changing the pump when changing the cambelts is recommended (however, pumps only cost £25 for them, only being £35 tops for a genuine item for a dealer). My theory on why waterpumps last longer is simple. Antifreeze technology has moved on alot. Red/Purple antifreeze (or any other OAT antifreeze (Blue and green are not OAT)) generally have better rust inhibitors in them in addition to having superior lubrication properties of the waterpump. My dad's Mondeo (which I had off him) did over 380,000 miles on the original waterpump. That's only ever been ran on Ford's 10 year antifreeze. When I broke the car, the water pump was still in perfect condition. When I went to PCT in Coventry, and EMC, both said the pumps were generally fine and best left, but PCT said to leave the tensioners claiming that they would make themselves known, although EMC did say that the tensioners on the cambelt can go awry.
Indi9xx
New member
The waterpumps can fail at any time... Its just very unusual for them to fail in under 80,000 miles, which is 2 cam belt changes... Typically they fail mechanically between 100,000 and 120,000 miles from experience... but there also seems to be an issue where they begin to leak with time... normally between 10 years old and 12 years old. The reason most experienced indi's recommend their replacement every second cam belt is that the failure point seems to be often half way through the life of a 3rd cam belt and we have a duty of care by law to advise the customer based on experience as well as following a schedule... If an indi tells you there is no need to change the pump at the same time as a 3rd belt change, the technician could be held liable if the pump failed early causing as little as a leak, or more worrying, caused an engine failure. Failure modes tend to include... Seizing - causing cam belt failure, bent valves and a good change of terminal engine failure. (normally occuring around 100,000 miles) impeller detatchment - often slipping when hot causing the car to run hot, when cooler it seems to act as normal - age related (possibly caused by heat cycling) Excessive movement - causing the belt tension to loosen, can cause a overheating due to lack of friction drive, or jumping teeth causing belt valves (see above) Leaking - Age related again - sometimes this can happen within 3000 miles of the 3rd belt change , probably due to increased load of a newly tensioned belt. Don't hate me, just saying it as it has been observed. I import the pumps direct from the manufacturer or from Porsche in Germany (often playing the two off against each other.. so tend to get a good deal!) PCarsGB tend to be non negotiable and therefore less likely to give a good deal.
Indi9xx
New member
You should not be getting 944 waterpumps with plastic impellers. AFAIK I normally get mine in bulk from Stuttgart direct and the last batch of 2.5NA, 2.5Turbo and 3.016v ones all had metal impellers. I know in the USA you get some iffy waterpump sources for the 944, often sold by NAPA.. not sure if its these ones which have plastic impellers. Also our waterpumps are new not the Porsche exchange ones, so maybe its the exchange ones which have plastic impellers?
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