I'm sonsidering replacing the water pump on my 01 325Ci but can't decide on which to buy. It seams several are offered and thought, well best way to find out about these is to ask you guys. Has any one had good or bad experience with either?
Stainless Steele alleviates serious issues associated with plastic impellers. No experience with composit. I think the "Stewart" is a great unit, but you don't have to pay that much just to upgrade to stainless Steele-
Plastic/composite is the same, after many heat cycles over the years they fail, plenty of info throughout the Internet on this. Stainless Steel, their are several companies to choose from all at different prices. I installed the Stewart water pump, 20% more flow and a larger bearing for support and with the idea I'll never have to change it again for preventative maintenance. I would review the different models and compare, see how they are made, some are cast, some are welded or machined just don't use plastic/composite.
Old one had plastic inside and it was visibly worn inside, even when didn't fail yet.
New one is all metal. It was 30***8364; + tax in october, and that company doesn't even offer any other kind except these.
Thanks guys for y'alls input. Im thinking of ordering from oembimmerparts.com
I've read great reviews on their customer service. Here are the ones they offer. They also offer a stewart but at a much higher price than these @ $174
Thanks guys for y'alls input. Im thinking of ordering from oembimmerparts.com
I've read great reviews on their customer service. Here are the ones they offer. They also offer a stewart but at a much higher price than these @ $174
If you plan on keeping the car a loooong time, the Stewart is a great choice. That's what I will put in when it's time. Much beefier front bearing. $125 extra is nothing compared to the damage failure can do. JMHO
I chose the Graf when I did mine. At 60k intervals for replacement... do not see a need to spend 3-4x on the Stewart. I track and Autocross and based my decision on extensive real world testing in extreme conditions. Never had a cooling issue even in 110* heat.
For a manual trans I agree. With the steptragic there is a lot of weight cantilevered off of the waterpump front bearing, so I'm going to "Upgrade". Probably overkill for sure, but when it's hot out, the clutch fan on mine screams like a banshee.
Composite or plastic impellers do break down over time with the various heat and cold cycles. When they do break down, they can and have sent little bits of plastic into the cooling system. If a plastic impeller does break down, where do these little pieces collect? They will get stuck somewhere.
Cooling system performance can take a hit with the lack of coolant flow from either an obstruction or lack of impeller surface area.
I will replace a plastic/composite impeller with a metal one at first chance. Bearings do not fail over night. They will give some type of warning. Metal impellers do not break down and send bits and pieces through the cooling system. Metal impellers can break away from the shaft and cause problems. It does not have to be a Stewart but it will be metal.
I had a plastic impeller break down at 60,000 miles on a VW Jetta. One of those little pieces got caught in the thermostat which caused a cooling system performance error. How much plastic was sent through the cooling system?
When I overhauled the cooling system on the ZHP I opted for the Stewart pump more for piece of mind and with the long-term possibility for f/I. If someone made a SS expansion tank for the non-m I'd jump on it. I also investigated silicon hoses and an aluminum radiator and decided the investment vs longevity wasn't worth it.
I just replaced my original water pump because it was leaking 4 days ago at 203,000 miles. Replaced with original BMW. I plan on driving it and foregoing a car payment as long as I can! I am just afraid of the metal impellers because if they do break or fail, it could really screw up the front of the engine where it is mounted. THAT would be expensive.
Impellars are not on the 'inside' of the waterpump. They are a part of the pump that goes inside the front of the engine. I have a friend who is a BMW Master Tech at the local dealer and he has seen them break apart before to where if it had been metal, it would have cost more than just a new water pump.
Impellars are not on the 'inside' of the waterpump. They are a part of the pump that goes inside the front of the engine. I have a friend who is a BMW Master Tech at the local dealer and he has seen them break apart before to where if it had been metal, it would have cost more than just a new water pump.
Why do you ask the question about impeller composition, if you know the answer? Ask your master tech friend if he has ever seen a metal impeller come apart and contaminate a cooling system? When a bearing fails sufficiently, the engine overheats due to loss of coolant and flow. If driven in an overheated condition catastrophic damage can occur. Obviously there are exceptions to typical overheat scenarios, but they are few. Install a metal impeller type pump, change it every 100k and forget about it- IMO.
On the E36s, the plastic impellers all broke apart and every garage in America was told to replace WPs with ones having metal impellers. Most still encourage using metal impellers based on that experience.
I ran your comment about metal impellers potentially damaging engines to my friend who is a 30 vet mechanic of Porsche, Mercedes, BMW and Audi. He laughed for about five minutes. He said that if the rest of your front end parts are made out of paper, yes - it could be possible for a metal impeller to damage something.
I guess it would be impossible for the metal impeller to gouge or chip into the aluminum block should the bearings start to go bad in the water pump. BMW should wise up sooner or later, since they are still not selling pumps with metal impellers.
He meant the weaker composite impellers BMW once used. I think one can still buy them from BMW.
By the way, your idea about impellers breaking and causing damage to the front end of the engine is not right. Composite impellers break by rubbing against the engine block. As someone else stated, pieces of broken composite impellers can contaminate the cooling system. The metal impellers do not break - the bearing merely fails on the WP. The kind of damage to the front end of an engine you described occurs when the shaft of a water pump breaks, which is totally different.
I put the Stewart WP in my ZHP when I replaced the cooling system. There really is no comparison. The Stewart is that much better made. I spend absolutely zero time thinking about a failed water pump and the $$ that would cost to fix. Get the Stewart and be done with it.
I would say that is a good life for original WP's with plastic or composite impellers that are lasting 100,000 miles +. I haven't heard any horror stories about original e46 WP's yet, though I have not searched for that info. It seems people replace them before any of them fail. I just ordered one with a metal impeller, my car now has 136,000 miles on it and the one in there is still working fine. If it is still the original WP that is in there now, I would have no problem replacing it with an oem WP again.
The weight doesn't matter in water. Any name brand water pump will be fine for 100k miles with regular coolant flushes. Outside of the forums the real experts consistently state this.
Yes, we know that the internet is overflowing with "experts". This forum may not have experts, but we have real world experience. Name brands can include inferior parts and rebranded parts; i.e. "Uro".
I wouldn't hesitate to spend the extra money if I were keeping the car long enough to need another pump at some point, but it's a long payback. Like I'm not going to convert my truck to electronic ignition because I can put new points in it for 25 years before recovering the cost of a conversion. Seems to me that non-metal-impeller pumps can be counted on to last around 60k safely, but like anything else you should regularly inspect it for issues. So if you plan to keep the car longer than that...
Hi, original poster here, the other day I cleaned my ICV and decided to take pictures of all the components while everything was apart. Well guess what I found on my 01 325ci with 138k,
The original radiator tank, which gives me to think all of the cooling system could be original. I think I'll consider replacing it soon.
Yes, the following is just my opinion... But, as I've posted above, just get the Stewart and be done with it. I can't understand why $100 difference would get in the way of proper maintenance and peace of mind in not having to worry about a silly water pump. These E46s are nice cars. Treat them well and enjoy the ride. If you take the "burger-flippin'" rate at Wendy's and multiply it times the number of hours we spend discussing water pumps, we could all have new Stewart pumps for free!
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