Composite or metal water pump impellers?

[78F350]

Originally Posted by 78F350

I'll be scrapping the engine that this pump came out of, or selling it cheap to someone who wants to part it or rebuild. Pieces of the composite impeller are somewhere in the engine and not coming out. Driven hard, it dumps coolant, then overheats (The cooling system has been replaced/tested).

Metal or composite? I don't care. Replace them about every 3 years and they should be fine. Wait 'till a failure and you can get bad results with either.

Pierburg makes good pumps, so does Geba, most forum members who are into this stuff will recommend the Pierburg.

By the time it makes noise or leaks it may have already shed plastic impeller debris that can end up in the cylinder heads.. While the majority of the failures that we see with cracked heads come from the 2000-01 engines we have seen this happen to engines as late a 2006. No matter mileage we change water pumps every 3 years, whether or not the engine is running the plastic impeller blades are exposed to coolant.

The metal impeller blades may not fail, BUT if you have a pump bearing failure the impeller "machines" the aluminum housing away and destroys the engine. Water pumps are cheap and easy to replace.
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Jake Raby
Flat 6 Innovations
Inventor of the IMS Solution:
US Patents 8,992,089 & 9,416,697

https://rennlist.com/forums/996-forum/666866-update-thoughts-on-preventative-water-pump-replacement-79k-my-03-a.html#post9051269

http://986forum.com/forums/boxster-general-discussions/60817-use-gt3-water-pump-metal-impeller-2.html