Water Pump Failure after 10K miles
 

On our 2002 4.4i, I replaced a broken water pump in Jan. 2008 when the car had 79,800 miles on it. Now car has 89,xxx miles and the water pump failed. Has anyone run across or heard of a possible bad batch of oem water pumps that might be failing prematurely. I understand these things aren't meant to last forever, but a failure after 10k miles/15 months driving just doesn't seem right. Plus, BMW parts are only warrantied for twelve months, so I'm screwed...this according to my mechanic, even though he is doing the job for 1/2 price. Any other possible causes :dunno:. Thanks.

BMW water pumps were/are weak (plastic impeller which breaks) but I thought they changed the design.

No way a water pump should only last 10k miles. Try bavarian autohaus in NH and call them for a better water pump (like 200USD)

all water pumps purchased from bmw have a lifetime warranty. only after 2 years is when you have to pay labor again. other items with lifetime warranty are shocks, starters, alternators, waterpumps.

I have heard of impeller failures, but that is too early.

Was it a bearing problem, or a leaking seal (which is often a result of a bearing failure)? If so, I would wonder about belt tension, a frequent cause of water pump failures on other models. There is a tensioner on your belt, but conceivably there could be a problem. Just guessing.

The 3.0 engine has a Stewart water pump replacement available with stainless steel impeller - the V8s are stuck with the plastic BMW part

i just had my water pump replaced by bmw...2005 4.4 with 17k miles...i bought it cpo in aug.2008 with 14k miles..

Could this be dealer specific? I had the dealer install a water pump recently and i believe i was told that it had a 2 year warranty. I'll have to check the paperwork.

Guys...can you all clarify two issues?

1) Confirm whether or not the 2 year parts warranty is correct. If so, then my indie mechanic who purchased the failed water pump should be able to get it replaced at no cost assuming he bought it from a BMW dealer parts department:dunno:.

2) What are the specs for the belt tensioner on the water pump? Would too loose or too tight cause premature failure?

BTW...looks as though the problem was a bearing failure in the pump. Thanks for all the input!

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The dealer specific question is a good one.
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Guys, I need your help!!!!
I just paid the dealer $1500 to replace the alternator, and within 2 days of having the car back, I find out my water pump main bearing has failed!! Dealer says this is unrelated and wants $1370 to replace!!!
What are the odds??? Could they have tightened the belts too much causing this failure?

Car is a 2004 with 110,000 miles


Any thoughts???? Please help guys - thank you

You need to find an Indie mechanic asap. You're getting ripped off back and forth. $1500 to replace an Alternator is highway robbery! :wow:

Any help guys?

Can improper belt tension cause water pump bearing failure?

Not a mechanic but;
Is not the belt tension determined by a tensioner pulley?
Wouldn't 110k more likely be the cause?
I paid 1300 bucks for a new alternator at the dealer, including 1 door ding removal.

Good luck.

I would still assume that you could screw up then tension though. The mechanic managed to leave the radiator completely loose as well, which I had to tighten down.

I know the mileage is high, but really, failure within hours of them messing with the belt system after the alternator repair?

I'm going to try and get the dealer to pay for the water pump, I'll let everyone know how it goes

no, the belt tensioner is what sets the belt tension. it is a mechanial design, and when turned to release the belt can not damage the water pump.

I understand that however I am sure you could still over tighten everything, regardless of the tensioner

I suggest you don't waste your time...it won't end well. It's perfectly normal for such a thing to happen, imo. I've definitely experienced it and learned that hard way that often times it's better to address a problem immediately as delaying will cause consequential damage to other components. There are other variables more likely to have caused the water pump failure than dealer negligence.

You've essentially received the same definitive answer that the dealer will give you...as a BMW certified tech (killcrap) just answered your question to improper belt tension causing water pump bearing failure.

My 2 tuppence...

Just FYI - dealer is paying for all labor for a new water pump, and they are throwing in a free thermostat as well. I will end up paying $500 instead of $1500.

I replaced a failed water pump on my 2002 4.4i a week ago. I used OE BMW parts ordered through ECS Tuning. My vehicle had 114K miles on it before total failure of the bearing. I mean, it DESTROYED the bearing. It took out the drive belt too. I suspect previous owners used non-BMW rated coolant like Peak. The used coolant did not have the right color and also smelled strange. Probably was never flushed or serviced.

The impeller is not the problem, regardless of material. The problem is either the belt tension and/or the coolant. The bearing/seals need proper lubrication which the BMW coolant can provide. Old or non-BMW coolant can cause problems leading to water pump failure.

The belt tensioner maintains the belt's tension, everything else is stationary. The water pump just failed extremely prematurely. If you get the pump from www.oembimmerparts.com they sell pumps with plastic and metal impellers. So you can choose which one you think is best. The pumps on average last about 80k miles or so. It's smart money to replace them at or before 100k if it hasn't failed.

Find an independent mechanic that has good prices and treat him like family. The dealer will always over-charge. Changing a water pump takes at worst two hours, hardest part is snatching the fan off. The part cost $117 + 2hrs labor = $317 before a little coolant, tax and shop fee. Anything over $350 is pushing it. (unless you are in a 3.0 and the pump costs $180)