Water pump failure: fact or fiction
#16
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Based on the poll from the other thread I'll be going with a new Laso, question is how can my nissan maxima with over 288K still have the factory WP. I guess being run by a chain in an oil bath lets them survive a lot longer.
#17
Drifting
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The PO of my 86.5 was very proud of the water pump with metal impeller he made great effort to locate. It's only been on about 2000 miles, with new timing belt, etc. Belt retentioned after 1500 miles (mechanic actually came to the house because the light had come on...no additional charge). No leaks, but after reading this thread I'm worried about it eating the block over time.
J
J
#19
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I sleep well knowing that I've got a very low probability of catastrophic failure due to the w.p. thanks to OBehave's Engine Guardian W.P..
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#20
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Some interesting posts/views.
I have not heard of that modified version of the pump before. Given that the pump takes very little power to do its job I have often wondered why they built it on the way they did. I know space is tight and maybe they felt they had no choice dimensionally,
What if any advantages does the Laso pump have over stock other than the large price difference?
I also found a web sight that had a pump design with the initials GMB pump- claiming it had improved flow rates over stock? Anyone know anything about this?
I remember John V's engine failure- shame that was- not sure I ever read anything about why it failed.
Regards
Fred
I have not heard of that modified version of the pump before. Given that the pump takes very little power to do its job I have often wondered why they built it on the way they did. I know space is tight and maybe they felt they had no choice dimensionally,
What if any advantages does the Laso pump have over stock other than the large price difference?
I also found a web sight that had a pump design with the initials GMB pump- claiming it had improved flow rates over stock? Anyone know anything about this?
I remember John V's engine failure- shame that was- not sure I ever read anything about why it failed.
Regards
Fred
#21
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My experience also, 12 year old 928 Intl rebuilt with about 30k on it, still on the car, still doing great (TB same age/miles). Will probably replace it soon when I do the belt with new Laso, but don't think they necessarily need to be replaced with every belt change. I'm going to replace because of age, and possible design improvements/plastic impellar.
#22
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that "GMB" pump is a crap Chinese knock off. Please don't consider it. As to the Laso over the Porsche pump, cost yes, but also the impeller and the mods done to the laso were done due to the requests of the community.
#23
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Looking at the history of my 88 S4, it had a water pump change at
68k in 1994
118k in 1996
no memtion of being rebuilt but they were both $209.
163k in 1998
this was a rebuilt pump from 928 Int. @ $99
And then nothing in the pile of invoices I have till I bought the car in 2007 and in 2010 at 285k I did the belt, cam gears etc. I fitted a Laso pump from Roger.
Judging by the amount crud on the front of the engine nobody had been in there for a long time, if that was the case the rebuilt had 122k on it, couldn't see anything wrong with it but with the age and the miles I replaced it.
The best option I had was to put my trust in a Laso.
Just some info and my 0.02 cents worth.
68k in 1994
118k in 1996
no memtion of being rebuilt but they were both $209.
163k in 1998
this was a rebuilt pump from 928 Int. @ $99
And then nothing in the pile of invoices I have till I bought the car in 2007 and in 2010 at 285k I did the belt, cam gears etc. I fitted a Laso pump from Roger.
Judging by the amount crud on the front of the engine nobody had been in there for a long time, if that was the case the rebuilt had 122k on it, couldn't see anything wrong with it but with the age and the miles I replaced it.
The best option I had was to put my trust in a Laso.
Just some info and my 0.02 cents worth.
#24
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I have replaced two pumps so far. Now on my third and recently I saw an item on ebay for a steal. I thought, what the heck, it would be at least a backup if I needed one. It is sitting on a shelf in my garage and I will use it if needed. It has a steel impeller.
As a retired aerospace pump engineer (brag, brag) I believe that plastic impellers are more prone to cavitation damage. We never use them on aircraft pumps. Incidentally, I paid $40 for the pump.
As a retired aerospace pump engineer (brag, brag) I believe that plastic impellers are more prone to cavitation damage. We never use them on aircraft pumps. Incidentally, I paid $40 for the pump.
#25
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Bjbpe,
What you bought was more than likley a Hamburg Technic Chinese knock off - best of luck with your purchase.
Roger
What you bought was more than likley a Hamburg Technic Chinese knock off - best of luck with your purchase.
Roger
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
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928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
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#26
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Laso reacted to the 928 Community and improved there pumps in line with our requirements.
Laso was never the OEM supplier to Porsche for the 928 WP but is the supplier for most of all the other pumps on P cars. They went out of their way to improve there pump to increase (thanks Glenn) MTBF.
The issue with rebuilt pumps is how many times they have been rebuilt. If you know the pump that was rebuilt was a first time rebuild then it is probably OK. I used to sell them until I realised that core return rebuilt pumps were being sent back for another rebuild without any record. The rebuild of rebuilds compromised the interferance fits of seal cartridge and the impeller. The high failure rate of the rebuilt pumps was the final nail in the coffin.
Laso was never the OEM supplier to Porsche for the 928 WP but is the supplier for most of all the other pumps on P cars. They went out of their way to improve there pump to increase (thanks Glenn) MTBF.
The issue with rebuilt pumps is how many times they have been rebuilt. If you know the pump that was rebuilt was a first time rebuild then it is probably OK. I used to sell them until I realised that core return rebuilt pumps were being sent back for another rebuild without any record. The rebuild of rebuilds compromised the interferance fits of seal cartridge and the impeller. The high failure rate of the rebuilt pumps was the final nail in the coffin.
Last edited by ROG100; 11-26-2011 at 01:43 PM.
#28
Nordschleife Master
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I think what Roger is politely trying to say above is that you've likely bought a cheap low-quality Chinese knock-off of the 928 pump, of a "brand" that has been discussed here on Rennlist a fair bit, and which 99% of us wouldn't consider installing.
#29
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Hi all
Other than a few of us on this forum that are seeing / repairing a lot of 928s, it's difficult to make a decision on this issue based on personal experience. I (we) simply don't have enough data.
After looking at/thinking about the design of the whole TB and water pump, I have come to the conclusion that it is simply one of the weakness (maybe design compromise of getting a V8 into such a small space) of these fantastic cars.
In view of this weakness, therefore, I would not take a risk on installing a rebuilt water pump and would only use the Laso pump.
JP
Other than a few of us on this forum that are seeing / repairing a lot of 928s, it's difficult to make a decision on this issue based on personal experience. I (we) simply don't have enough data.
After looking at/thinking about the design of the whole TB and water pump, I have come to the conclusion that it is simply one of the weakness (maybe design compromise of getting a V8 into such a small space) of these fantastic cars.
In view of this weakness, therefore, I would not take a risk on installing a rebuilt water pump and would only use the Laso pump.
JP
#30
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Some intersting points of view/experiences here. I guess what makes me think a bit more is this:
To revamp a water pump requiresthe following logical steps:
1. Receive and handle the old pump
2. Degrease/clean the carcass
3. Remove existing pinion
4. Inspect the carcass
5. Refurbish the carcass [?]
6. Acquire replacement parts/inventory/catalogue/store
7. Reassemble with new components
8. Test the assembly
9. Pack and distribute to resellers
10. Reseller profit margin [10%?]
When looked at in this perspective not sure it can make economic sense from a business point of view if all the refurbisher can recover is $100. If the carcasses are packed off enmasse to a sweat shop in the far east maybe- but what price quality? If the work is carried out in the US how can it be done for that price?
I'm pretty sure I know where my next WP will be coming from.
Regards
Fred
To revamp a water pump requiresthe following logical steps:
1. Receive and handle the old pump
2. Degrease/clean the carcass
3. Remove existing pinion
4. Inspect the carcass
5. Refurbish the carcass [?]
6. Acquire replacement parts/inventory/catalogue/store
7. Reassemble with new components
8. Test the assembly
9. Pack and distribute to resellers
10. Reseller profit margin [10%?]
When looked at in this perspective not sure it can make economic sense from a business point of view if all the refurbisher can recover is $100. If the carcasses are packed off enmasse to a sweat shop in the far east maybe- but what price quality? If the work is carried out in the US how can it be done for that price?
I'm pretty sure I know where my next WP will be coming from.
Regards
Fred