Der Sportwagen

September / October 2016 14 TECHNICAL EDITOR By Karl Wilen A s we end another hot season and move forward into the cooler weather, one thing remains the same….your water cooled Porsche's cooling system is another year older! Since the water cooled Porsche's came out back in the late 70's and early 80's, it was common knowledge to replace those water pumps on a regular basis as preventa- tive maintenance. Back in those days, the water pump rode on the timing belt, and a pump failure could have catastrophic ef- fects on the motor. While the mechanism is slightly different on today's engines, the results of a failed pump can still have a big impact on your wallet. I've touched on this subject before, but feel it is important to re- stress as new buyers are attracted to these cars with their affordable buy in pricing. While there is no timing belt to worry about on the modern water cooled engines, the pumps still fail as often if not more. Symptoms of a failing water pump can man- ifest as a "pulley noise", grinding noise, or a small drip of coolant underneath the car. It might even burn the belt and cause a rub- ber smell as the pulley wobbles and eats the drive belt. Here you can see the water pump location on an M96/M97 engine with the front ac- cess cover removed. This pump's bearing had starting play, allowing the impeller to make contact with the pump housing and shatter. The factory pumps come with a plastic impeller which can explode apart once the bearing starts to get play in it, and it can send those little plastic bits through your cooling system, into the cylinder heads, and Photos by Karl Wilen Hot Water WATERPUMP BLUES

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