BMW E46 Waterpump

[nk_zhp]

Folks, from what I understand the new water pumps from BMW use an improved composite impeller that is supposed to be top notch quality. After scavenging RealOEM I can see that the new part number went into effect 04/2003. Does this mean that post 04/03 cars have the new one. I personally would assume so. The reason why I ask is that this whole E46 cooling system i think has become a cash cow. Initially water pumps were failing early because of the plastic impeller so 60K became a preventative mark. With the composite impeller I don't know if 60 is where it should be.

Any thoughts?

[zhp43867]

It isn't that expensive by itself, I'd just replace it. If you DIY the whole kit it is not expensive really. You may or may not have the composite impeller pump (which isn't bulletproof); do you like to gamble?

http://www.bimmerzone.com/BMW_Parts_Cooling_Package/PKG-E46-COOLING-MANUAL.html

Just substitute the GRAF pump for OEM, I think it adds like $40. Not a bad deal.

[kayger12]

Have been researching this myself lately as I'm getting within 10k miles of a coolant overhaul. BMW has supposedly improved both the water pump and the expansion tank, both of which seem to be the main targets of the preventative coolant overhaul.

From what I've read, BMW stopped using the plastic/resin impellers in the water pumps some time ago, however, I can't find a definitive date that this occurred.

That being said, I've also read that even with the composite or stainless impellers, pumps were experiencing a bearing failure at around 80K which is obviously just as devastating to the engine.

I think you're on to something with the whole cash cow thing-- but I also think a lot of us love our cars too much to take the chance.

Fwiw, my 325i (manufactured 6/03 iirc) went to almost 100k before I did the overhaul (bought it with 95K) and the only failure item was the thermostat. Original pump and expansion tank were still doing their job.

Personally, at this point I'm gonna stick with the 60K mark until I see some more evidence to convince me that it's safe to do otherwise.

Definitely interested to see what info others turn up, though.

[kayger12]

Ok-- some more digging shows that the pumps have gone through 3 generations of impellers.

Original was metal impeller which was prone to bearing failure. 2nd gen was plastic impeller which was the impeller that was known for failure. BMW then went to 3rd gen which is the composite impeller which is supposedly not prone to either bearing or impeller failure. Of course, I can't find any dates to go along with those changes yet, but here are the P/Ns

11-51-7-527-799 (metal) was superceded by:
11-51-7-503-884 (plastic). This PN then was superceded by:
11-51-7-527-910 (composite).

The bearing failure info I found was in a bav auto blog from earlier this year, but according to them, BMW went from a plastic to a metal impeller, which seems to contradict all of the other info out there... :confused

Interesting discussion here (http://forums.bimmerforums.com/forum/showthread.php?t=1164740)

[nk_zhp]

Well, we all know fear sells. Take the radiator for example. Typically radiators don't just fail out of the blue, they start bleeding coolant slowly so it's something that should be inspected on a periodic basis. T-stats typically fail by staying open, meaning too cool and not too hot, often observed as the temp needle dropping at highway speeds. Expansion tank yes... it burst suddenly and sudden pump failures I can buy into as well. Hoses can go 80-90 miles easy. I at times feel the cooling issue on E46s has become kind of like the sub frame failure case, it's there but not in as large of quantities as people are lead to believe.

[nk_zhp]

p/n ... 910 went into effect 04/2003.

[Marcus-SanDiego]

Moved to maintenance forum.

[kayger12]

p/n ... 910 went into effect 04/2003.

Looks like we've all got the good pump then. Or at least the better of the pumps...

[nk_zhp]

I call for a group fist pump (no pun intended)

...dude... I couldn't find this thread all of a sudden... then realized it moved.

[kayger12]

I call for a group fist pump (no pun intended)

...dude... I couldn't find this thread all of a sudden... then realized it moved.

http://dgold.info/emoticons/green/fist-knucks-simple.gif

[nk_zhp]

^ now that's funny!

[FullyBalanced]

I figure I'm hitting 60k in 2k, so I'm replacing with a Stewart pump to be safe

[Marcus-SanDiego]

I just swapped out my water pump. Used the OEM pump. This car doesn't see any track time. I have 59,000 miles on the ODO. Since my pump was still in fine working condition, I kept it. I have it in my parts room.

[danewilson77]

I did not read all pages....but I recommend the impeller that is of a composite material.

[Jon D]

Well just make us feel batter my 97 Audi A4 had an expansion tank failure as well at about 125K and my 05 A4 had a bleed screw pop out so BMW not the only one where coolant system stuff can be an issue

[kayger12]

Nk- was just reading the December Roundel issue and there was a question in the Tech Talk section about cooling system overhaul and whether the water pumps are improved over the ones that we needed to replace every 60k.

At this time the well respected tech recommends water pump and thermostat at 60k, radiator, exp tank, plastic cooling fan, upper and lower hoses at 90k, and the other coolant and fuel hoses at 150k.

Said that he knows of no update to the oem pump that resolves the premature failure issues.

[Mtnman]

well crap. i have 135k on mine, and havent done any of that. This forum is expensive! :)

[pyreguy]

^ :rofl

[jjcools]

well crap. i have 135k on mine, and havent done any of that. This forum is expensive! :)

Ditto on the expensive part. It would be more expensive to fail but for some reason, my mind works different and just sees the price I pay for fear of potential failure :)

[3ZHPGUY]

I talked to a guy I work with about just changing my water pump. I actually met a few years before we worked together at an all German car show. He has been heavy into Bimmers & Porsche for years. He told me that i should have put in at Stewart pump saying they are bullet proof.

http://www.stewartcomponents.net/Merchant2/graphics/00000001/Basket_Contents.gif

http://www.stewartcomponents.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=BMWHPWP

[3ZHPGUY]

I talked to a guy I work with about just changing my water pump. I actually met a few years before we worked together at an all German car show. He has been heavy into Bimmers & Porsche for years. He told me that i should have put in at Stewart pump saying they are bullet proof.

http://www.stewartcomponents.net/Merchant2/graphics/00000001/Basket_Contents.gif

http://www.stewartcomponents.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=BMWHPWP

[Linh]

Before looking into the OEM composite wp, I had already bought the kit with the metal impeller. But upon researching, I feel that the main problems with metal impeller wp's is premature bearing failure. I've also heard about composite OEM bearing going bad too (E46 M3) at around 80k. But people have gone up to 130-140k with no overhaul of the cooling system, but even then, its usually the T-stat or expansion tanks that gives up first.

I recently check the water pump bearings/shaft and it had no play or wobbling @102k miles. Right now, I'm more worried about the expansion tank exploding, which I will change soon when flushing the coolant.

[danewilson77]

Right now, I'm more worried about the expansion tank exploding.....

Hear, hear....

[Linh]

Haha. . Yes Dane, you will be getting some PM's soon =)

[FullyBalanced]

Nk- was just reading the December Roundel issue and there was a question in the Tech Talk section about cooling system overhaul and whether the water pumps are improved over the ones that we needed to replace every 60k.

At this time the well respected tech recommends water pump and thermostat at 60k, radiator, exp tank, plastic cooling fan, upper and lower hoses at 90k, and the other coolant and fuel hoses at 150k.

Said that he knows of no update to the oem pump that resolves the premature failure issues.

that was regarding a 540i....I don't know if they have the same pump or not.

[FullyBalanced]

I talked to a guy I work with about just changing my water pump. I actually met a few years before we worked together at an all German car show. He has been heavy into Bimmers & Porsche for years. He told me that i should have put in at Stewart pump saying they are bullet proof.

http://www.stewartcomponents.net/Merchant2/graphics/00000001/Basket_Contents.gif

http://www.stewartcomponents.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=BMWHPWP

They have a lifetime warranty so I figured go ahead and get it in there!

[az3579]

They have a lifetime warranty so I figured go ahead and get it in there!

Problem is, the warranty isn't worth jack if it fails on you because you're still left stranded and still have to pay to get it fixed (if you don't do your own work). Plus, you'll be out a car for at least a few days while waiting for the replacement.

To me, it's greater peace of mind to replace it every 60k. I can't afford to have one fail on me during a track day because then not only will I be stranded very far from home, but I will have lost whatever money I dumped on the track day as well.

[shadowpuck]

so far, everything i've read is pretty complimentary of the stewart pump. i've assisted with the install of one in an e36 with a track-prepped motor and no issues so far.

i've also had no problems at all with BMW OEM water pumps using tech talk's maintenance interval - including my track car, which is at 189k and going strong.

general bmw cooling system rules apply - keep the coolant up to code, check for leaks and damage, don't over tighten the hose clamps, and address any issues immediately.

i have witnessed a radiator failure with no prior warning - so its possible. i don't think its fear mongering, but rather another piece of information to know.
agreed, though, the odds of a radiator up and dying without any prior notice is pretty rare.

[kayger12]

Yeah- I even googled to try and dig up some Stewart pump failure hits, but came up empty...

[quikryptonite]

So, I am on the TMS site searching for a composite water pump and I find this P/N 11517527910. It says that it is a fit for my car, but redirects me to this P/N 11517509985. This part number comes with with a "thumbs down" for my 2003 330i. But, it says that it fits the following BMW's (1999-2006 E46 3 series - 323i, 323Ci, 328i, 328Ci, 325i, 325Ci, 330i, 330Ci). Isn't this the new P/N that BMW is using: Part #: 11517509985 | Composite WP (http://www.turnermotorsport.com/p-1030-water-pump-m52tu-m54-original-bmw.aspx)

Have any of you used this P/N on your cars? It looks like it should fit.

BavAuto is giving me this when I search for that P/N
Substitution! We sell the same part as a different number. You searched for: 11 51 7 509 985
We sell the same part as: 11 51 7 527 910

ECSTuning comes up with a fit for my E46 M54 330i.

I think I should be good ordering that part from TMS. I am getting the power pulleys too and wanted to save on shipping.