What are the pros/cons of the various BMW E39 replacement water pumps?

oops.

I am with Mack here and the others who chose the Stewart pump.
The added 20% efficiency will do nicely with the TMS underdrive pulleys and the NPG+. The day is approaching fast. Can't wait.

Yeah man. I want to do the NPG at some point. Stewart HP still going strong at 30k+ miles.

Originally Posted by Mack

Yeah man. I want to do the NPG at some point. Stewart HP still going strong at 30k+ miles.

It should. Especially with the TMS underdrive pulleys, she turns slower, so less rpm's on the bearing. She should last like forever - lifetime LOL.

I'm planning on it. At least I know my trani will last forever. According to BMW anyways.

There is a very good discussion of the various water pumps in part 1 of this video referenced today by bobdmac:

BMW Cooling System Failure Points, Part 1 (e36, e46, e34, e39):


BMW Cooling System Failure Points, Part 2 (e36, e46, e34, e39):

For the waterpump record, this thread discusses the fallibility of both the plastic OEM and tack-welded metal Graf versus the cast metal Geba water pump impellers ...
- Catastrophic water pump faliure!

GEBA water-pump:

http://www.ecstuning.com/BMW-E39-525..._Pump/ES10753/

Appears as though the Stewart/EMB is only for a 525 or 530. Of the remaining options any recommendations for a 2003 540/6 (68k miles) as I think mine is beginning to crater? I'm leaning toward metal versus composite option. Don't worry, I'll be replacing the entire cooling system at the same time.

Originally Posted by bakdoc66

Appears as though the Stewart/EMB is only for a 525 or 530. Of the remaining options any recommendations for a 2003 540/6 (68k miles) as I think mine is beginning to crater? I'm leaning toward metal versus composite option. Don't worry, I'll be replacing the entire cooling system at the same time.

Way to be proactive!

Originally Posted by bluebee

There is a very good discussion of the various water pumps in part 1 of this video referenced today by bobdmac:

BMW Cooling System Failure Points, Part 1 (e36, e46, e34, e39):

That's a great video. Damn I'm glad I went with the Stewart EMP.

Originally Posted by Mack

glad I went with the Stewart EMP.

By way of cross reference:
- E39 (1997 - 2003) > Hepu vs. Stewart waterpump

Just for the record, there is a mystery waterpump (cast not machined impeller) discussed here today:
- E39 (1997 - 2003) > Help Identify This Water Pump

BB thanks for the help. It appears this pump is a Geba made back in 2009.

Originally Posted by S C H I T zo

It appears this pump is a Geba made back in 2009.

Glad you figured it out.

BTW, today, there was a good discussion on the water pump pulley and what are our replacement options (including aluminum from EAC Tuning):
- E39 (1997 - 2003) > Mechanical Fan Exploded! Is another one Justified?

But not everyone has the aluminum option ...

Originally Posted by cn90

1997-2003: Same Water Pump PN for all these years

1997-?09/1998: Different WP Pulley and Different Belt Length compared with later years
?10/1998-2003: Different WP Pulley and Different Belt Length compared with earlier years

The bottom line is for my 1998 528i (build date 10/1997), I do not have the Aluminum WP Pulley option.

For the record, there is a similar discussion started recently over here by a relative newbie who might not have known this has been discussed before:
- E39 (1997 - 2003) > GMB water pump? any good?

Originally Posted by andrewyoussef

I found a really good deal on it at autozone 36$ brand new. What do you guys think? should I get it or stick to another well known brand?

For the record, the following was posted today related to the OEM waterpump brand:
- E39 (1997 - 2003) > OEM water pump?

Originally Posted by E39_Ryda

I ordered an OEM water pump for my 530i and noticed that it's made by Saleri. I've never heard of this brand before and couldn't find much info on it.

Visual comparison: old water pump has composite impeller that's stamped with "INA" & "Germany". New water pump also has a composite impeller with "Germany" and "WPB" stampings, but I noticed extra material towards the bottom of the water pump (see pic). Plus the box for the new water pump says it's Made in Italy. So what is it....Germany or Italy?

Does anyone have experience with this water pump?

For the cross-linked record, this user experience was posted today:
- E39 (1997 - 2003) > GMB water pump

Originally Posted by Dmendez

I just want to share with you what happened to my baby a month ago.

I heard over intervals of time while waiting at a red light a noise like metal scraping metal. I thought for a moment that the fan was hitting the cover. I looked at the instrument panel, no light turned on, nor was heating up.

I park and I noticed that the water pump bearing was broken. You could see the shaft of the water pump going up and down.

I bought the car just over two years ago with 84k miles on it and now has about 120k. The previous owner had done the cooling system so I decided to change the water pump only. I love DIY so I change the water pump myself with a cheap one I got from Advance Auto. $ 45 for the GMB water pump and $ 24 for the original BMW coolant.

I know some will disagree but my point is that the work is very easy to do and only took me an hour an a half. If it happens again I will use the Stewart EMP. I wonder how much the mechanic would have charged for it?
Already drove it for about 1k miles and everything has been fine.

For cross reference, this was opened today:
- > E39 (1997 - 2003) > Cooling System Refresh - Stewart WP?

Originally Posted by ianbsmith

So the time has finally come to overhaul my cooling system. I just had a question, I was looking into getting the Stewart WP because of the various claimed advantages (SS impeller, good bearings, increased flow). I don't really have a problem with the price but my question is this: the rest of the cooling system will be restored with OEM parts (including behr Rad unless someone can convince me otherwise). Will the Stewart water pump and its increased "flow" make the other parts inclined to fail faster? Or will I be ok with all stock minus the Stewart?

172k on the clock and Stewart EMP still kickin'!

How many of those miles were on the Stewart, Mack?

IIRC I'm thinking about 40 to 50k or so. Minimum. Pretty sure I had my cooling overhaul done at 120k'ish. WP included of course.

The Saleri water pump came up again today, over here:

Originally Posted by FLE39

Did a power search for the water pump, wow. what options. that is a nice link you gave me the other day ^ ! The big question now is what brand water pump do I get??? HEPU, Graf, Meyele, GMB, Saleri. Plastic or metal impeller? I need to get another 100k out of it.

Edit: After searching around the Saleri seems to be the "OEM" deal, and then HEPU & GRAF. GMB & Meyle on the lower tiers for budgets. Am I right? I'm looking at a Saleri, HEPU or GRAF. help me decide.


Edit 2: After more searching I'm ready to pull the trigger on a Saleri pump from RMeuroparts. Any reason not to go this route?

Originally Posted by Mack

172k on the clock and Stewart EMP still kickin'!

I have been using the Stewart EMP in my 97 328iC for 3 years and 30K miles with excellent results. Shortly after I did the install, my upper radiator hose blew off while my wife had the car at the supermarket 8 miles from home. (Apparently, the chief mechanic forgot to tighten the hose clamp. That would be me.) She did not understand what had happened and called me to say the low oil light just came on. I figured it was just a flaky oil pan sensor because I had just changed the oil and filter while doing the cooling system work. She drove it home with no coolant and severely overheated the engine. It was making some very frightening sounds as she drove up the driveway. The low oil light was not on. It was the overtemp warning light!!!! The cast iron 2.8 M52 is one tough engine. It survived this event and has been running well in daily use ever since. All I did was change fluids and fire it up.

The Stewart EMP survived high temps and running dry and is still working well 3 years later. I also installed this pump on my E34 with S52 swap and will install it on the E39 530i 5 spd I am picking up on Friday. It is worth every penny.

Based on cost and availability I went with a waterpump from Advanced, we have a few of the stores near me so if mine fails I'll be able to get the replacement for free. To me there is NOTHING particularly 'robust' with our cooling systems, this is a known weak spot in the E39 line. It certainly does not make it a 'show stopper' but, as we all know the cooling system is certainly somethign all of us E39'ers are familiar with and know well. If we get 3-4 years out of a cooling system component then we consider ourselves lucky. I know there are site sponsors, and the popular sentiment here is to use OEM. Logically speaking that is all good, but from an owners and DIY'ers perspective you need to have a price/performance paypoint and there is no performance gain by using any of the 'OEM' components therefore price would be a deciding factor. When you can pay for one water pump and end up with 2 or 3 before you sell the car, it only makes sense to get one with a lifetime warranty, same with Radiator, expansion tank, hoses, clutch fan etc...