Boxster/996 Waterpumps

This problem has been popping up on a very regular basis on the Boxster and 996 engines.  So much, that I think I am going to start recommending waterpump replacement at about the 80k mile or 10 year mark as that is about when they seem to be failing. Failure can be leakage from the bearing weep hole, and if that is let go for more than a few days, the bearing and impeller are going to explode. Not a pretty sight.

We had done a full service on this boxster a few months ago. When the belt was replaced, the pump still felt good and tight (check it any time your belt is off). Well obviously she finally let go and threw the 5k mile belt off and destroyed that. Doh!

Here you can see the belt hanging down and the coolant leak.

Waterpump is located on the bottom corner of the engine.

The pulley was hanging off the pump, so I suspected the interal impeller had exploded….I was right. The waterpump impellers are made of plastic, and so it stands to reason that over time the plastic will become brittle due to the heat, and eventually come apart.

Since I had pieces of impeller laying in the cooling system, I pulled the thermostat housing to clear it of any debris and also flush the system of debris

I found a few bearing pieces here in the valley and was able to clear it all out. Then I pulled the hose to the thermostat and flushed the forward lines.

Tomorrow night I will get the new pump installed and back on the road!


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February 22, 2011 at 9:02 AM

Are you replacing with same plastic impeller? Is there an aftermarket “solid” impeller? Maybe I should have this done as well, since I’m at 52k miles and the impeller is approx 8 years old on reman engine.


February 22, 2011 at 9:22 AM

Hey Doug,

I have not found a pump with a metal impeller…yet. The bearing is part of the failure, so I don’t think there will be any advantage to going to a metal impeller as the pump is still going to come apart at the bearing.

Kevin A

February 22, 2011 at 10:01 AM

Still sounds like a real opportunity for one of the aftermarket companies to produce a more reliable substitute pump…bearing and all. But if the originals last 10 years…maybe it’s not worth the R&D/fabrication expense.


February 22, 2011 at 10:03 AM

Yea, the history of german waterpumps is all the same. Replace them every 8-10 years or 60k miles which ever comes first…or they will fail. Turns out the boxster/996 is no different. I have seen these pumps fail with as little as 30k miles on them.

Keith Shoemaker

March 22, 2011 at 11:34 PM

Thinking about buying a 99′ Boxster. Any way I can get service records from dealer on car? Sounds like it will need a water pump if it has not been changed. Any other advice for me.



    March 23, 2011 at 8:14 AM

    Hi Keith,

    Dealers do not have a national database of vehicle repairs. If you can find the dealer (or independent shop) the car was serviced at, you might be able to talk them into releasing the records. Many will not though, as they consider it privacy invasion. Just depends on the dealer. If buying the car from the dealer, then you can tell them they must show you the service records before buying, and of course they will always comply in that situation 😉

      Keith Shoemaker

      March 23, 2011 at 10:03 AM

      Thanks for feedback. Was not sure if it could be checked by VIN or not.
      2 owner car, guy picked up at CarMax auction last month. CarFax is OK, but as you know I want to get it checked out before purchase.

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