Ed Petry

Hello everyone,

Hope your driving season was enjoyable (yes, I live in snow territory). Mine was great, got my shark on the road after a multi-year nap. Less fire and braking issues, clutch and most safety systems are secure. Now on to other issues.

An old question but my turn to learn about the different impellers. I searched the forum and see various data / opinions / ideas in a number of posts but not a concise discussion. My search tags must not be formed properly (recurring issue for me).

I know the fear is the metal impeller moves to the rear and gouges the block. Not good at all.
The plastic impeller, if it does loosen and move to the rear, is the part that suffers. Better.

From what I read the answer is the plastic impeller type.

Yet,, the metal impeller has better expansion / contraction properties under the difference in temperature and from what I read (elsewhere on Porsche forums) flexes less and therefore pushes more coolant.

I know one block is too many if it's your motor. How many blocks suffered this damage over the years? Was this a common, wide spread issue?

Thanks in advance.

buccicone

Ed:

Which pump did you put on the motor when you did the timing belt. I believe universal consensus is the Laso with the plastic impeller. If you bought it from Roger you are good.

FredR

So many of these things have gouged out the block that Greg Brown invented a repair tool to deal with it! The notion that the metal impeller is better hydraulically than the plastic impeller for want of a better word is nonsense. Put another way Porsche did not change to the plastic impeller to save money.

If one wants to take the risk of gouging the block for whatever reason then said person gets what they deserve if the casing is gouged. Once that happens the block is more or less useless unless and until a repair can be effected. Doubtless many folks will say they have used the metal impeller without issue- perhaps better to ask the [many] ones who were not so fortunate what they think of the metal impeller pumps. For sure I would not entertain one having had pumps that threw the plastic impeller twice- just glad there was plastic in there.

Ladybug83

Laso w/ plastic impeller is on sale now at 928sRUS! (No affiliation)

linderpat

yes; call Roger and stock up. I still have an extra one from his last sale. Great price and the correct water pump.

buccicone

Ordered 2 last night............

The Forgotten On

Porsche went to plastic impellers in 89 for a reason....