Yikes! I could buy 5 or 6 of the pumps I just put on my car for what one of those costs! I don't get all this fuss about BMW cooling systems. I don't have any overheating problems, so why would I need a high performance pump that is just goig to rob power and reduce fuel economy?
I noticed no power loss, or fuel economy loss after installing the pump. I'd rather do the job once, do it right, and not have to mess with it again. I'm willing to pay for a bit of overkill as it gives me piece of mind.
For a car that won't ever see track time, or hard use--- the standard pump is probably fine for another 100K miles or so. My car gets used in a variety of conditions, so I opted for the beefier pump.
The fuss about BMW cooling systems stems from the fact that the plastic they used ( for the radiator inlets, the water pump impellers, and the engine fan) fail over time-- creating issues. These problems can be fixed using the stock pieces every 80-100K miles or so----or they can be solved permanently by using more robust components.
Some folks don't plan on keeping their cars permanently....some do.
Some of the radiator problems were/are because broken motor mounts will cause the engine to tear off the water necks and people never check them until the fan smashes itself on the shroud. Autocross and track work are hard on motor mounts.
Some are because the plastic deteriorates but that is usually on the expansion tank on the E36. I did replace mine with an all aluminum radiator + tank (because race car) and kept the stock one (w/ 140k and still perfectly serviceable) as a backup in the trailer. With some of the newer affordable aluminum options - it isn't more expensive so it's a legitimate no-cost upgrade for the street when the time comes.
Some are myths... there were a bad batch of OE water pumps with composite impellers back in the mid-90s (twice, actually) so gospel was use the metal impeller ones but they fixed it a long time ago and any BMW water pump is fine. I'm not sure I would trust the $35 Cheng-Shen ones at Advanced with the big cast iron impellers but the OE suppliers (Behr, etc) will be ok.
I use any non-phosphorus type coolant that is safe for aluminum engines. Back when 99% of engines were cast iron you couldn't find it anywhere but dealers. GM had aluminum heads but if you mixed that "special" orange crap in there you had a real mess on your hands... so gospel advice - only use the blue stuff from BMW (which is Zerex). Everything has an aluminum cylinder head these days and you can buy the same Zerex from Walmart.
I think a lot of people don't get that some of the more vocal people posting advice on bimmerforums are vendors feeding their own till. The crackpot broken record in Roundel doesn't help much either.
The energy to pump more water has to come from the engine itself. It may not be noticeable, but it does take power to do it.
I also like to do a job once and be done with it, but that stewart warner pump is pure overkill, IMHO (at least for me). It took me about an hour to change my water pump and belts, and I took my time. Its not like I was replacing the rod bearings or something like that, in which case I would only use the best components. In addition, I see plastic cooling components on all kinds of cars all the time. Maybe the cooling components don't last as long as some other cars, but those cars have components that don't last as long as a BMW. My point is stuff goes wrong with cars as they age. I just don't see the point in spending $500 to replace my entire cooling system when only my water pump is bad. I'll replace those other components when they go bad. I wouldn't replace my transmission because my driveshaft is bad either...
In reply to Giant Purple Snorklewacker:
I took the time to investigate the BMW coolant thing, and then went to the auto parts store and looked at the coolants they had on display. I don't live anywhere near a BMW dealer, and I needed to get the car back on the road. Nevertheless, I wasn't going to do something that could damage my engine. I used Peak, which stated right on the bottle that it was non-phosphorous and safe for all engines. I'm not worried about it. And I agree with your statement about vendors trying to create business, and that prior problems with certain vehicles get blown out of proportion and perpetuated long after they are solved. Then there's the interwebz experts that are just flat out wrong. So in a case like this, I read all that stuff, look at my car and it's condition, the cost and labor of doing a comprehensive job versus just doing what's necessary, and decide what to do. This time I decided to just do what was necessary, since everything else appeared to be in good shape and was easily accessible when/if I have to repair them in the future, so I'm not going to be retracing a lot of steps then that I do now. It makes sense to me in this situation. In another I might do something different.
Like GPS I also went all-out on my 330ci's cooling system, but I put the car together for track days Road America, which is a pretty punishing high-speed course. I wouldn't begrudge anyone for going with OE-spec components, but like anything else, you gotta pick the right tool for the job, and it sounds like you did just that.
FWIW - BMW coolant is exactly the same as Pentosin G11 which can be found at most NAPA stores. Good to know if you need some in a pinch.
bravenrace wrote: The energy to pump more water has to come from the engine itself. It may not be noticeable, but it does take power to do it.
Are they pumping more water by brute force or are they pumping water because they cavitate/recirculate internally less?
The SW pump pictured suggests they went the efficiency route.
This is why I prefer plastic impellers on my personal cars, they tend to be designed a lot better than the iron ones. If i HAVE to go iron, I spend an hour or so smoothing/porting the casting knobs and ugliness off of the impeller.
Sheetmetal is right out. Don't return it, just scrap it so nobody else has to tolerate that junk. Take one for the team.
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