Water pump - plastic or metal?

Quick question - going to do a wp change on a e36/m52 what is the best waterpump to use for - Is there a oem metal impeller wp? or something better? - Thanks in advance Dave

__________________
This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW Water Pump Replacement

[Wayne 962]

I've heard of issues with both styles of pumps. If it were my car though, I would opt for the metal impeller pumps (which are the aftermarket ones - OEM / Genuine ones are still plastic).

- Wayne

[Manolito]

The premium pump of choice is the Stewart pump with an oversized bearing and a stainless impeller, if you are willing to pay triple the price of a standard pump. I might use it if I had done fan deletes on my cars.

The standard replacement pump is the Graf, which has a metal impeller made of sheet metal spot welded together. It looks really cheap but seems to hold up just fine.

Bosch and several other vendors make pumps to fit the e36, but I have never heard any reports on any of those.

Interestingly, both my '97 328s came new with BMW branded pumps with metal impellers in them that looked like the Graf. The impeller stood up OK, it was the seal that wore out. Bearing play was not noticeable when they failed.

[Yurick]

I think that Graf is the brand of choice by BMW.

[bostogrun]

I bought a 97 328i. I was concerned about the plastic water pump so I opted to preemptively
to put a new one in. (The local BMW Dealer wanted $288 to check to see what kind of the water pump I had and $500 to install a new one if they found a plastic one). The orginal one was a GAF with metal fins. Because the original one was good I installed it in an older 525i M50 I had. Between the two cars, it lasted about 180K before it failed. I think thats about the service life of a water pump. I think anything above 150K is borrowed time for a water pump.

Would you rather fix it in your garage or break down on the road or worse yet have your wife or kid keep driving after it's overheated and blow the headgasket.

[jamin325i]

original lasted 53k miles-impeller separated.

replaced w/graf metal which lasted 47k-shaft broke.

replaced w/$tealer w.p. now having about 23k miles. in a hurry so never inquired at dealer about pump details until a year later w/purchase in my hand. asked what rm meant on receipt;they said reman. i had not requested a reman.
i asked them what material; they claimed they did not know. they went and got a sample which they claimed similar to what i had bought. i tapped it w/keys, impeller appeared metal. they agreed.

still don't know what is source of dealer reman w.p.'s.

don't know type of material or manufacturer of pumps they sell new.

have been on several bimmer forums since owning this car, but have never heard who makes bmw oe w.p.'s.
would appreciate comments from bimmer service people on this subject.

regardless, i will be changing out the pump when working in that area when it has 50k miles of use in the future.
-------------------------------------------------------------------
in re-reading thread in sunk in that you guys are pretty convinced graf is the oe if metal. if plastic is still made as oe, who is manufacturer?

[bostogrun]

I have found that OEM BMW parts aren't any better than aftermarket copies. Case in point my brake light switch, a very common failure, I installed one at 100k with one from Autozone and it went out in 25k. I bellied up the extra $ for a genuine BMW one and guess what it went out in 25K. The current water pump in my E36 is a forty dollar metal impellered one from O'Rielly and it's still going strong after 60k.