Water Pump Failure

[winfred]

not safe to drive, if it is a failed plastic impeller or a bad thermostat things can go bad quickly and change a $100 repair to a $1000

[ironie]

Winfred makes a good point actually. Thatr plastic impeller is specific to BMW.
I have never seen another car with it. Traditional water pump failures are usally pretty obvious due to the fact that they leak from the shaft. My M50 has almost 170k on it and had had the water pump done at least once, and when it failed it failed in the traditional manner, I had no fear of increasing the revs as opposed to sitting in traffic on a hot day idleing, Heat builds up quicker and is disipates more slowly at low revs. Reving the engine up forces the water through the system faster (if you have a impellor left)
The plastic impellor really is one of BMW dumber ideas. I assume they figured this out as well and gave it up in later models

[Bill R.]

Not quite, a number of car companies now use a water pump with a plastic or composite impeller, mercedes, vw, bmw and a number of others now are starting to use more and more plastics. They don't seem to have the problems that they did in the past.

Winfred makes a good point actually. Thatr plastic impeller is specific to BMW.
I have never seen another car with it. Traditional water pump failures are usally pretty obvious due to the fact that they leak from the shaft. My M50 has almost 170k on it and had had the water pump done at least once, and when it failed it failed in the traditional manner, I had no fear of increasing the revs as opposed to sitting in traffic on a hot day idleing, Heat builds up quicker and is disipates more slowly at low revs. Reving the engine up forces the water through the system faster (if you have a impellor left)
The plastic impellor really is one of BMW dumber ideas. I assume they figured this out as well and gave it up in later models