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Fixed his own HPFP
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Howdy E65 land! Its been awhile. :wave:

I wanted to share some information about the water pumps on Amazon Prime selling for around $40 - they are the same as the URO brand pumps that sell for twice as much (or more).

I bought both the URO and the "No Name" $40 pump, and they were IDENTICAL. Same numbers stamped into them, same light blue dabs of paint strategically located on them. They are THE SAME PUMP. :thumbup:

These "URO" type pumps use METAL impellers, which some seem to believe is superior to plastic. My original BMW pump with plastic lasted 190K, so I'm not sure if that's true. But I digress. :dunno:

I installed mine yesterday. The water pump is really not too bad a job on these cars - just make sure the large rubber gasket stays put in its little groove when installing the pump. Mine didn't, and I couldn't figure out why the car was leaking. Cost me a an afternoon to take it all back apart, plus the cost of the blue coolant I lost. Turns out the gasket got squeezed and cut in two. :mad:

Rather than wait for a $15 replacement gasket to be sent (for a $40 pump), I just used blue RTV to form a gasket on it and it sealed up like Fort Knox. :bigpimp:

I will keep you guys updated if I have any issues with the pump's longevity.

PART TWO: Aluminum replacement water pump pulley

When my water pump failed, it took the plastic water pump pulley with it. I wanted an aluminum aftermarket replacement, which I found for the v-8 models but not my v-12. Knowing from past experience MANY parts are interchangeable between the 760 and 745, I ordered the aluminum pulley for the 745 V8. It fit my 760 v12 just fine, but it was about a half-inch larger in diameter. Almost as if BMW engineers placed an overdrive (smaller) pulley on the v12's to make the water pump run faster. So now my water pump rotates more slowly, but I've noticed no effect so far in the 104* Texas heat.

When I went to reinstall the serpentine belt, it wouldn't fit! I had to order a 1600mm belt to replace the standard 1550mm belt. The extra 5cm gave me enough extra that it would fit over the new larger aluminum pulley.

Part Three: Fan clutch

While I had everything apart, I decided to replace the fan clutch. I had an issue whereupon if I sat stopped for long enough, my a/c would stop blowing cold. I thought it was the electric fan and replaced it, but there was no change in behaviour.

So it occurred to me that a weak fan clutch could be the culprit. BMW wanted something like $250 for the clutch, or I could buy one off Amazon for about $30. They are easy to change, literally takes less than 10 minutes, so I didn't think it would be much of a risk to try it.

Upon receipt, I noticed how much more resistance to turning there was on the new clutch. This was a sign my old one was shot after 190K.

I installed the $30 clutch, went for a drive to check the water pump for leaks, then left the car parked while running, on a 104* day. Came back 10 minutes later and the A/C was still blowing cold! :D

So if you lose a/c when not in motion, but your electric fan works, its more than likely your worn out fan clutch!

So at the end of the day, I replaced my water pump, pulley, fan clutch, and serpentine belt all for about $120. Who says V12 BMW's are expensive to maintain??? LOL
 
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