HenryPcar

Now that my 997.2 is close to 10 years, as a preventive measure I have on my list to change the water pump. Apparently there is a bug fuss over at the BMW forum which I used to visit, about the E90's water pump comes with plastic impellers and they have a tendency to disintegrate resulting in huge damage to the engine. In checking the water pumps of the 997.2,, it seems the original Porsche ones also come with plastic impellers. Now there are after-market water pumps that has metal impellers. Has there been instances of Porsche water pump damage due to plastic impeller breakage, or should I stick to the stock version ?

linderpat

You should always use a pump with a plastic impeller. When the shaft begins to fail, and causes the impeller to migrate forward, a metal impeller will mill the engine block and destroy it. A plastic impeller will break apart first, and not ruin the block. I believe Porsche no longer supplies pumps with metal impellers.

Shred

So far it seems the waterpump in the 997.2 is more 'reliable' than previous gen.

Mike Murphy

Petza914

+1 and this info is Exactly correct !

As the bearing gradually wears and the angle of deflection it will start to file down the plastic impeller which should make very fine plastic dust, not chunks. If it goes too long and the bearing angle gets too great, that's when the plastic impeller will break off shards of plastic and those shards can lodge in the narrow coolant passages, causing hot-spots in the motor, which is bad. This is why I'm a proponent of proactive water pump replacement, before failure occurs..

HenryPcar

Thanks for all the input. Yes, I'lll just order the Porsche pump.
On another point. Does the original pump come with a flat gasket that might require applying a sealant on it, or does it come with a rubber gasket that just bolts down without applying sealant.

Petza914

It comes with a metal gasket. I use my fingers to smear high-temp sealant on both sides of the metal gasket before reassembly - not a bead, just a thin smear layer.

Qwksnke

I have been curious about this as well. Haven't really came across much info about 997.2's prematurely failing like the .1's

ChicagoSpeed996

Just to clarify a couple posts on this thread and to answer some of your questions. The posts on this thread seem to be discussing 997.1 water pump design and gaskets. The 997.2 is a completely different animal. Porsche addressed some of the short comings of the 996-997.1 water pump design. The new design has captured fins to prevent disintegration and breaking off of fins that used to get lodged into the heads and cause hotspots. Also, the gasket design is now an o-ring, no sealant necessary, but a very clean surface is crucial. The water pump will come with the gasket (I believe as it has been a while since I did mine on my previous 997.2). You can ask the dealership where you get it from. I get my stuff from Porsche atlanta or Sunset.

HenryPcar

Thanks ChicagoSpeed996.
What is captured fins ?

DesmoSD

Since Porsche's have been air cooled for such a long time, I feel they are still evolving when it comes to water cooling as mentioned by Chicagospeed996 with their water pump designs. Cracked coolant reservoirs, coolant reservoir caps not sealing, coolant lines coming loose etc. Coming from Japanese sports cars that have metal blades, it's rare for fins to break loose, heck even cause engine damage. When a WP fails, the car overheats due to impeller bearing going out and the impeller no longer spinning.

Are there statistics of OEM water pumps actually causing engine damage on 911's or othe German cars that use the plastic impellers?

yelcab

And this is why I replace my wife's 997 water pump at 60K miles. The water pump is one of those things that ... if it goes, leads to engine blow up when driven by my wife. The solution is change it before it blows.

Robocop305

I'm a firm believer that if it's not broken, don't fix it. A water pump failure should give some warning, ie leak, noise, etc. Just be conscious of your car and you should be fine.

sandwedge

The pump on my -09 C4S failed at 40K miles. Could be an outlier but I've read of enough failures in the 45K to 60K range to take note. Got 58K on the GTS now with the original pump so thinking about proactive replacement.

See above.

Absolutely no warning at all on my -09 failure. No funny noises, no small puddles or even drops of coolant on the garage floor (yes, I do check the garage floor often for things like this). Nothing. Was just driving along and all of a sudden I started seeing steam from the engine through the rear window along along a slow rise in coolant temp. Big mess back there since the serp. belt was trashed when the pump froze up.

Mike Murphy