the flyin' scotsman

The facts:

'90 GT, recent import from Japan, no maintenance history.

antifreeze solution was weak...........very pale green in colour.

the WP was replaced at some time; from my experience the 'new' pump is a Laso with the shaft sleeve and metal impeller (see pics).

the block had been 'rubbed' at some point in time by the WP.

there's no evidence on the installed WP impeller of contact.

Question: should the WP be replaced?

NoVector

Malcolm - If you don't, would you wait another 5 years to replace it?

I'm doing the TB/WP on my GTS now due to a "noise" coming from the water pump area. I just got the belt off an hour ago and will take the WP off when the new one arrives. It looks like it's pulley for the impeller--it has a lot of play and I have very fine glitter all over the smooth side of the belt. Personally, I'd spend the $$ for the piece of mind. Had my pump froze and it popped the belt... wow.

DR

Is the shiney part on the very outer edge of the impellor vane at 9:00 glare from the camera, or ????

Mrmerlin

Malcolm if the there is a slight resistance on the bearing while its being turned, and the pump has no side to side play, and its not leaking coolant then it can be reused

Lizard928

As Stan implies, it is determined on the bearing carrier more than the pump.

Maybe take some playdough and stick it to the face and check to see how much clearance to the block you have.

the flyin' scotsman

Thx all..............I relooked at the WP.

Dave, the shine seen in the pics is from the camera flash.

Stan, Colin.............do either of you have a new Laso pump to compare? I ask as the impeller is not flush with the end of the shaft but is toward the block by a few mm's. Not sure if it should be flush.

I have a pic of a new Laso pump somewhere.

blown 87

This is just me, but I am never going to put another "Stock Type" cast impeller WP in my car again.

To many possible failure points that can end up with the impeller into the block.

ROG100

Malcolm,
I have 6 Laso pumps sitting here what do you need to know?
The shaft and the outside edge of the impeller should be flush.
Looks right in your picture.
Roger

jcorenman

Malcom,

From the pic's in post#1, that looks like the "new style" Laso with a bushing between the impeller and shaft. See Roger's post here.

If that is correct then it must have been replaced since that post date at the end of 2008.

From Roger's pic it looks like the shaft is a little below flush, but only a mm or so?? Clay would tell the tale...

It is also hard to argue with Greg's comment on cast impellers... What are the plastic impeller choices these days? Porsche rebuilt's?

blown 87

Is there any ETA on the Lasso pumps with the plastic impellers yet?

SQLGuy

But the plastic ones come loose on the shaft and then your car overheats. There has to be some better choice than a slippling plastic impeller or a chewing the block metal one.

Giovanni

If it overheats you turn it off... if the metal impellers comes loose it will also overheats, the only thing it that it will be too late then and your block will need some extensive repair.

ROG100

The plastic impeller Laso pumps are made but will not get into the supply chain until the existing stocks are used up. My main Wholesaler has about 15 in stock with another 20 arriving next week.
I will have a visual done on one of the 20 to see if it is plastic or not.

Only choice at the moment for a new pump with plastic impeller is Porsche Factory. My current price is $1011 OUCH! Price went up in March.
I will not touch a rebuild.

the flyin' scotsman

Many thx Jim...........thats what I wanted to see. Indeed the shaft is a little below flush in Rogers pic and on the WP thats on the GT......they are identical

From these observations I conclude that the marks on the block must have happened with the old WP, the installed WP is the newer Laso version and appears in good shape.

I have tugged and wiggled the impeller and pulley; there's no movement so I'm inclined to put it back on.

Roger, please add a WP gasket to the package.........the Porsche WP will have to sit on the shelf.

SQLGuy

Not exactly. The reason for the metal impeller chewing into the block that I have seen is migration of the shaft, not a loose impeller. If the impeller were loose it wouldn't have torque to chew into the block. My block chewing '85 water pump didn't leak and didn't overheat. It was just replaced as SOP by my mechanic at the time who then noticed the damage.

Roger, has the reason for either of these problems (shaft migration, slipping plastic impellers) been identified/addressed by Laso?

Does Porken have an outboard electric pump retrofit for the 928 yet? ;-)

Thanks,
Paul