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      01-30-2013, 07:43 AM   #80
Lieutenant General

Drives: E90 & Z4 Coupe
Join Date: May 2012
Location: MARLAND

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Originally Posted by index1489 View Post
The miles before the pump fails is irrelevant, it fails after hours of operation not miles.

1 car could have 150k miles and driven X hours (lets say lots of freeway driving)

2 car could have 75k miles and driven X hours (lots of city traffic stuck at lights)

They could both have the same amount of operating hours and the pump fails around the same time.

Of course when people say the pump failed at 30k or whatever thats just a defective pump.
Not sure I agree with this totally. The pump fails because the electronic control components are mounted on the rear of the pump housing and are heat cycled to death. I think the failure is more of a function of heat soak rather than just pure running time of the pump. Meaning, a two cars could have the same operating time at different mileages, but if one car is in Dallas, Texas, and the other in Juneau, Alaska, I'd bet the Alaskan car's pump would last longer.