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Hey, over the weekend I had a water pump failure. Have some input on a few things i noticed before the failure which I will post to this thread tonight.

Just want to get the questions out there so I can get parts ordered.

Front bearing on pump is completely gone. I took the pump off. I plan on replacing the pump, O-ring gasket. What else would be a good idea to replace. Thinking about the thermostat housing? Also the pulley is plastic no visual cracks or damage. I see the new Genuine BMW brand pumps have a composite impeller. The pump I removed has a metal impeller. Has anyone used the composite ones?

Any info on parts to replace and info on metal or composite impeller would be greatly appreciated.
 

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:D
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if your cooling system has never been serviced it's a good idea to replace everything. even the radiator. my water pump, radiator, and expansion tank all failed within 5k miles of each other. all of them will leave you stranded.

the composite impeller is fine. i've had mine running for years now without problem.
 

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OEM ///PLUS
2003 M3 6MT Slicktop
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pump and thermostat are always suggested.

on this forum now you'll hear people say to just replace it all. although having all new is a good thing, i'm not about replacing parts blindly that might have 100,000 miles use left in them. so how many miles on your car and has anything been replaced?

if you don't know history of parts and parts like WP are going out then it's a good chance system is worn/neglected. seeing how important the cooling system is in the M52/M54 it's often best to bite the bullet and replace most of the system.
but import things are WP, T-stat and expansion tank.
 

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Check the condition of the belt you just took off. Any cracks I would replace it also since you have it dangling at this point. Check your hoses too for signs of wear. If the expansion tank is the original, it's just a matter of time before it fails.
 

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I will be doing the same thing on my 02 tomorrow. Been noticing low on anti-freeze the last month or so. Cleaned up everything under the car and notice this afternoon anti-freeze dripping off of the sway bar. Replaced it about 8 years ago. Not bad for a car with over 225,000 miles. Also replaced one on my 2000 Silverado with 333,456 miles.:hi:
 

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its really a no brainer to do a cooling system overhaul for any E46 now...
the youngest E46 is almost 9 years old
all the thermoplastic parts are past their designed life by now
its 400-500 from OEMbimmerparts its not too bad of a job
best of luck
 

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Do all three pulleys...and belts...and ET...and if you don't know the hoses have been done, do them...in other words, full Mangofication!

If money is tight, you can save yourself some headaches...at least do pump and therm as mentioned above. You can also 'just' replace the o-rings in the hoses to save you some headaches.

Fill first time with distilled water...then a second time even. Make sure it's clean when you put BMW coolant in.
 

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Another do it all. First I just did the Radiator and the Expansion tank and cap because they were leaking. I wanted to just do the entire thing but i talked myself out of it, Then a few thousand miles later, the thermostat went. Then a few more miles BAM the water pump went and took the pullies with it. Then A few weeks after that I started smelling coolant and the screw on the upper hose popped under pressure......save yourself the headache and do it all now.
 

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I agree on doing it all. If its affordable for you just replace everything and have some piece of mind. Having to pay for a tow truck when you are stranded on the side of the road gets pricey. Trust me it happened to me twice because of my cooling system. First my expansion tank failed and then about a week later after it was replaced my radiator failed. I'm also sure the people at best buy will never look at me the same for spilling all my coolant on their brand new parking lot. A massive stain I feel compelled to park next to each time I go there :) If you have the slightest bit of mechanical know how do it yourself and save a lot of money. It's really not a hard job. I learned the hard way and after 2 tow trucks a mechanic and then eventually doing a lot of the work myself it came to around $1800. If i just replaced everything myself it would have easily been under $800. That's using mostly OEM parts I did go for the Saleri water pump.
 
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