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My water pump has failed in a way that I haven't seen mentioned in Rennlist or elsewhere.
Hearing an unusual noise on starting the 928 a few days ago I checked under the bonnet to see the water pump pulley apparently attempting a daring escape via the front engine cover...
Caught mid-escape!
On removal of the front cover, this is what I found:
Back of cover Pulley at an unusual angle, belt barely hanging on
The timing belt and the front cover were all that was holding the pulley in place. Once the belt was removed, the pulley simply fell off the shaft.
Anyone seen this before? Any idea how it could have happened?
BTW it was a metal impeller Laso, installed in 2009 (around 20k miles since then). I replaced the timing belt (but not the WP) with a Continental belt just over 18 months ago (only about 6k miles since then) and rechecked tension as per schedule - no issues at the time.
WP bearings are fine, the shaft still turns smoothly, has almost no play, and the rear impeller is fine. No block damage, and no overheating, but the change in tension at the WP pulley must have been retarding timing on the 1-4 bank. It didn't appear that any cam teeth were jumped, despite the belt being much looser. As this is a 1982 car, it doesn't have a belt tension warning light, so no warnings until noise at startup.
Presently waiting for new WP, tensioner rollers, timing belt.... as this is a Euro, not sure if there would have been valve and piston collisions should the pulley have fully exited via the front cover.... possibly bullet dodged!
Never seen this one before. Looks like you got away with it and the block has not been damaged.
I used and use LASO for more than 25 years now on friends Porsches and mine too. No issues....
Let us know what else you find (or not hopefully)...
Was the timing belt running forward on the cam gears?
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Wow...that could have been a real disaster, on a Euro engine!
Just before 928 International quit selling rebuilt water pumps, this became fairly common on those pumps. I had several that failed exactly like this. (Which is why he quit selling them, I believe.)
Simple matter of there not being enough of a press fit of the front pulley onto the bearing cartridge.
When it comes to low grade water pumps:
"If it can, it will."
There's a client's car on one of our lifts getting a new timing belt, as I type this.
It's been 16,000 miles and 11 years since the belt was changed and a new water pump installed.
He paid $900 for a factory water pump and $100 for a factory timing belt (11 years ago), so we planned on it just needing a new belt.
The water pump was a "Leaking Laso" [in a new (*see below), possibly different way] and the belt was a Gates. (Selling a Laso at factory prices is the same as stealing, in my eyes!)
(*) Normally, we get to see aftermarket pumps which have a bad bearing (for no obvious reason) or an aftermarket pump with a coolant leak. This particular "Laso failure" is a bit different.....Maybe!
There is grease coming out of the weep hole in the pump, not coolant!
And the bearing is noisy.
Apparently, the seal on the bearing which retains the grease has failed and enough of the grease (there's not very much to start with) has come for the bearing to fail.
So the Maybe! part:
Is this a normal/common failure? Do I only get to see these pumps after the bearing has completely failed and the seal (on the "water side") fails? The hot steamy water would wash away all traces of this grease....and remove the clue of the real cause of the failure!
Could this be the real cause of all the failures I see and hear about?
To answer Roger's question, the cam belt had moved somewhat to the forward edge of the 5-8 cam, not so much the 1-4 cam. The belt itself was largely undamaged, but I'm replacing it anyway of course.
Greg - AFAIK this was a new Laso that was installed in 2009, not a rebuilt unit (PO paid more than $AU500 for it, not including installation, by Australia's most reputable 928 specialist at the time). I had heard of rebuilt units failing like this, but not new ones. This pump wasn't leaking at all when the pulley and shaft parted company.
As it happens, I'm replacing this Laso with another new Laso (plastic impeller rather than metal being perhaps the only difference). I haven't recently priced a water pump from Porsche here in Australia but last I heard they were in the vicinity of $AU2000, so Laso is next best it seems! Anyway, I now have a new "observation window" in the front cover so I can keep an eye on the pulley from now on... ;-)
To answer Roger's question, the cam belt had moved somewhat to the forward edge of the 5-8 cam, not so much the 1-4 cam. The belt itself was largely undamaged, but I'm replacing it anyway of course.
Greg - AFAIK this was a new Laso that was installed in 2009, not a rebuilt unit (PO paid more than $AU500 for it, not including installation, by Australia's most reputable 928 specialist at the time). I had heard of rebuilt units failing like this, but not new ones. This pump wasn't leaking at all when the pulley and shaft parted company.
As it happens, I'm replacing this Laso with another new Laso (plastic impeller rather than metal being perhaps the only difference). I haven't recently priced a water pump from Porsche here in Australia but last I heard they were in the vicinity of $AU2000, so Laso is next best it seems! Anyway, I now have a new "observation window" in the front cover so I can keep an eye on the pulley from now on... ;-)
David
Apparently, from what Roger says, I have a collection of the world's most unlucky customers. I haven't seen a Laso last over 20,000 miles in so long, I simply can't remember one.
You are lucky. You have the ability to do this job yourself and apparently you don't drive this car very much/far.
So, if the pump lasts another 10 years...you probably won't care.
Here in California, most of my clients apparently drive their cars a bit more than in other places in the world.
If I tell most of my clients that their new water pump will likely not last for 20,000 miles, most of them would have a fit, since that may be less than a couple of years of use.
And here, the price difference between a Laso and a factory pump is less than 50%. (You can't buy two Laso's for the price I charge for one Porsche pump.)
And the 50% difference, in price, won't pay for half the labor involved.
Plus the fact that after 2 years, the warranty on the Laso will be over....and the client will need to buy another one!
Except in rare situations, selling one of my clients a Laso water pump is not only a "false economy" move for them, but is contrary to my moral values.
I've just received the new replacement Laso pump. I'm now wondering though if the failed pump was a new one as I had believed (fitted by PO's tech, so I don't have any direct knowledge). Here are comparison pics of old and new pulleys. Old failed pump.
New Laso
What's interesting is the peening on the face of the pulley around the shaft of the old pump. New one doesn't have this. Is the peening an indicator that the old pump was actually a rebuilt unit, or have Laso simply changed their manufacturing processes in the 12 or so years since that pump was originally fitted?
If it's an indicator that the old pump was rebuilt, then that does change the nature of the failure - would seem to be a rebuilding failure (as you originally suggested Greg) rather than a design or manufacturing fault.
The old pump is not OEM LASO, this is IMHO certainly a rebuilt. Whoever did this tried to increase the pulleys pressure on the WP shaft.
Below two pictures of OEM LASO pumps both pictures are about 15 years old. One pump is for a 951 the other one shows my GTS. 951 pump My GTS 2006 new LASO and 1st gen PorKensioner (so going strong with no issues).
Agree with Schocki - a definite rebuild.
This was at a time when rebuilt water pumps were considered the norm by most owners. Then we began to see rebuild of rebuilds and the failures started.
I will not sell rebuilt pumps and have not done so for a number of years now. We have two choices of new pumps with plastic impellers - Laso at $350 and Porsche $1100 - you pay your money and takes your choice.
Sounds like the verdict is in then - rebuilt pump fail. Good to know, in a way, that it was not a new pump that failed in this way. Anyway, I have the new Laso installed now and I have high hopes for it lasting longer than Greg's 20,000 miles benchmark!
I've just received the new replacement Laso pump. I'm now wondering though if the failed pump was a new one as I had believed (fitted by PO's tech, so I don't have any direct knowledge). Here are comparison pics of old and new pulleys. Old failed pump.
New Laso
What's interesting is the peening on the face of the pulley around the shaft of the old pump. New one doesn't have this. Is the peening an indicator that the old pump was actually a rebuilt unit, or have Laso simply changed their manufacturing processes in the 12 or so years since that pump was originally fitted?
If it's an indicator that the old pump was rebuilt, then that does change the nature of the failure - would seem to be a rebuilding failure (as you originally suggested Greg) rather than a design or manufacturing fault.
David
1982 S Manual
I'd be willing to be the farm that those peen marks did not occur at Laso.
Or at any reputable rebuilder.
On top of that minor detail, that pulley appears to have a Porsche "stamp" on it.
Laso would not be able to do that.
I believe that a Laso at $350 is a discounted price.
So, to compare apples with apples,
I think you'd need to compare Sunset's price on a factory water pump at $683.66.
Basically twice the price, but 10x the quality and 4-5 times the average life span.
This whole "water pump thing" is the true definition of "false economy"....
And it is not solely a "German water pump thing".
The same exact scenario occurs with American water pumps....
But a factory GM water pump for a Suburban and change it every 120,000 miles, whether it needs it or not.
Buy a Pep Boy's water pump (1/3 the price) and change it every 30,000 miles.(If you are lucky.)
......And if you talk to a German about a Laso pump, you find out that the brand has about the same reputation, in Germany, as a Pep Boy's water pump, here.
There's a saying that says "You gets what you pays for".
Not always true, but especially true about water pumps....
......And if you talk to a German about a Laso pump, you find out that the brand has about the same reputation, in Germany, as a Pep Boy's water pump, here.
There's a saying that says "You gets what you pays for".
Not always true, but especially true about water pumps....
I think I'm qualified to comment on this statement. No, LASO is not known in the Porsche 928 community as cheap or Pep Boys quality. Most 928 owners use them and we have close to zero issues.
As I stated before I have used them now for over 25 years in my Porsches and friends 928s without a single problem.
08-19-2021, 02:35 AM
Unusual water pump failure?
George Layton March 2014
