986 Forum - The Community for Porsche Boxster & Cayman Owners

- Boxster General Discussions (http://986forum.com/forums/forumdisplay.php?f=5)

- - high labor for water pump/thermostat? (http://986forum.com/forums/showthread.php?t=82976)

Quote:

Originally Posted by JFP in PA (Post 650974)

No idea. But this is what kind of damage metal impellers cause when the blades hit the case:

https://cimg6.ibsrv.net/gimg/rennlis...5de875b00.jpeg

Hey JFP, and is the problem then that with the gouging now, the new pump won't flow coolant as well due to the clearance or is there a danger of the pump grinding into an oil passage or other leak? And how does this damage manifest itself in the future? Overheating? How long does this type of damage take to occur on a failing pump? I realize there are variables but just trying to understand if once it starts, the driver can hear noise and react or does it happen too quickly to react or so slowly that nothing is heard?

Also, how likely are the broken off plastic impeller bits to cause problems in the cooling system? And if so, what is the cure to removing them for shops such as yourself? (I dread to think but still would like to know the solution if any, whether it's a flush or requires engine disassembly that is not cost effective.)

Many thanks.

The case wear caused by metal impeller contact results in both reduced coolant flow rates, which if severe enough can cause overheating issues, and it can also cause fine metal to clog smaller coolant passages with the same outcome.

How long it takes to cause severe damage is relative to how badly the pump is wobbling and how often the car is driven in this condition. I have not heard of noise complaints related to this wear, but that can also be because the pump bearing is making so much noise that the impeller related sound is masked.

Basically, anything extraneous should be kept out of the cooling system, and the composite impeller bits can cause similar issues. Shops usually resort to reverse flow flushing the cooling system to try to dislodge impeller bits. If it is really bad, engine disassembly and ultrasonic cleaning baths are the next step.

For what it's worth, 4 years ago, I had my water pump replaced by my "indy" Porsche shop because it was leaking (20 year old original water pump).....I was charged $1,200 for the pump, labor and coolant. (Chicago area)

Quote:

Originally Posted by Rob175 (Post 651140)

Hey,
Can you share a name/phone # for your indy? I need to get a key coded if possible, and get some other work done...