Replaced water pump

[jeebus87]

My 3.0si coupe just rolled past 70k miles and I figured I was running on borrowed time with the original water pump and t-stat so I had those prophylactically replaced today. Cost me right at $900 bucks at my Indy for OEM parts and a couple hours of labor. Is there any data to indicate that newer/revised water pumps will last longer? Or is it simply general BMW knowledge that water pumps are a frequent source of failure?

[Dalecan]

That's a lot of money for something that might have lasted another 20-30k miles.

[jeebus87]

I don't know about that, seems to be on par with what I've seen other N52 owners pay.

And I have to make a couple long roadtrips in the near future so I can't afford to be stranded, I saw a thread on the e90 forum and it looks like a whole lot of water pumps fail around the 70-80k mark.

[The HACK]

Originally Posted by Dalecan

That's a lot of money for something that might have lasted another 20-30k miles.

It's because it's one of those new-fangled ELECTRICALLY driven pumps, not mechanically driven. They are freakishly expensive to replace, even compared to the the S54 water pump (which is expensive to replace because of location, not parts cost).

The electric pump is actually one of those that I wouldn't replace prematurely. I'd wait until it dies before replacing, because unlike mechanical pumps, they don't grenade and take the engine with them. If your electric water pump dies, you'll get a quick warning and have a few minutes to shut down the engine. The mechanical pumps have a small chance of a catastrophic failure where the composite/plastic fan will break and lodge itself in various water passages.

The newer composite fans are far less likely to break like that.

[Vanne]

Hack, good point, any way to see if you have a new composite pump? the PO never kept any receipts for anything on my car.

[Twixboy]

Are water pumps prone to failure due to age or mileage? I have the M54 and wonder if I need to proactively replace mine due to age (11 years) rather than mileage (58k miles). I'm pretty sure I have a plastic impeller/fan.

[XMetal]

Originally Posted by Twixboy

Are water pumps prone to failure due to age or mileage? I have the M54 and wonder if I need to proactively replace mine due to age (11 years) rather than mileage (58k miles). I'm pretty sure I have a plastic impeller/fan.

I believed both depending on climates/usage. Preventative maintenance will always be a hot debatable subject. For what it's worth, I've always replaced water pumps/T-stats on all my cars at around 100K miles or 10 years. Fearing the imminent failures of the composite impeller, I had replaced mine on my M54 X5 at around 80K (around 8-year old). I'll do the same when my MC had reached year #10.

[Karacticus]

The one electric water pump I did see fail (on an E91 wagon at a track day) failed gracefully -- wouldn't go into "high demand" mode. The failure was annunciated, along with a minor boil-over of the expansion tank, but it maintained a limp mode.

[The HACK]

Originally Posted by Vanne

Hack, good point, any way to see if you have a new composite pump? the PO never kept any receipts for anything on my car.

They stopped making the plastic fan blade pumps in 199X. Anything made between 1997-2003 (except the E46 M3) has metal fan blades. Anything made AFTER that (including all the S54 variants) has composite fan blades. The composite fan blades are suppose to last longer than plastic.

The problem with them mechanical pump with composite fan blades aren't that the fan blades fail, it'll fail because of bearing issues. The electrical pumps, since they're driven by an electric motor, doesn't suffer the same mechanical bearing issue...But they're prone to electrical issues. Hence replace when dead.

I'd proactively replace the newer composite water pumps at around 100,000 miles. Or 10 years. Whichever one comes first.

[The HACK]

Originally Posted by Twixboy

Are water pumps prone to failure due to age or mileage? I have the M54 and wonder if I need to proactively replace mine due to age (11 years) rather than mileage (58k miles). I'm pretty sure I have a plastic impeller/fan.

No, you'll have either a metal impeller blade or a composite (it's some sort of weird metal mesh with plastic/ceramic coating from what I've seen). The failure point is the bearing, which mainly "ages" through use. The new(er) pumps will last for around 90-120K miles.

I've also seen some fail around 10-12 years regardless of miles driven (a friend had late 2000 Z3 that had the pump fail around 2009 at 50,000 miles. Bearing seized). I would proactively replace it if I were in your shoes, especially since you have an M5X where you can use the Steward water pump. They're high-flow and are made for high end motorsports (think endurance racing) so they last FOREVER. I've seen E30 race cars that use the Steward pump and raced for over 10 years and still running strong.

[The HACK]

Originally Posted by Karacticus

The one electric water pump I did see fail (on an E91 wagon at a track day) failed gracefully -- wouldn't go into "high demand" mode. The failure was annunciated, along with a minor boil-over of the expansion tank, but it maintained a limp mode.

Yep.

[dc_wright]

Mine gave a low rpm fault but was still pumping when I replaced it. There's a tachometer output on the pump and the DME monitors it to ensure it's turning the appropriate speed. (N52 3.0si)

[trevor]

Originally Posted by jeebus87

My 3.0si coupe just rolled past 70k miles and I figured I was running on borrowed time with the original water pump and t-stat so I had those prophylactically replaced today. Cost me right at $900 bucks at my Indy for OEM parts and a couple hours of labor. Is there any data to indicate that newer/revised water pumps will last longer? Or is it simply general BMW knowledge that water pumps are a frequent source of failure?

For starters, don't go to the dealership, they're overpriced and untrustworthy. Dealerships in my area break stuff on purpose (big crack on new windshield of my Z4 and claimed I came in like that.. even altered documents to get away with it).

A water pump shouldn't go bad that fast, I would say it directly reflects how well you are taking care of the car and the way you are driving. Not saying it's bad, just saying to work on improving.

Don't floor it too much, make sure you don't leave your car in the sun too much, etc.. just a bunch of basic stuff.