[Mark e90]

Reading through different threads on here I notice that the water pump seems to be a common problem with the petrol e90. However after noticing this I decided to search through the UK BMW forums and can't find any trace of problems on there with the e90, there is a few that have failed but only older models e46 etc. I spoke to my mechanic and he also says he has never done one on an e90 but only older models.

I'm just wondering if the lifespan of the water pump could be affected by the climate ? As Scotland is mostly always cold so mabay the pump doesn't need to work as hard ?

[X5-User]

Waterpump we have is an electric one...and it is the electronics part that fails on these waterpump. I really doubt it has anything to do with climate. I live in Northen part of US and it is also pretty colder than rest of US and my electric waterpump still failed at 60k

[PascalsWager]

Did euro-spec E90's get a different water pump?

[Fun w/N54]

I second that...live in Wisconsin and pump failed at 54k or 4 years and 2 months after in service.

[Gizm0]

What kills electric pumps is the high number of start/stops per hour. The electric motor will last much longer if it's ran for an extended period.

[galahad05]

Originally Posted by Gizm0

What kills electric pumps is the high number of start/stops per hour. The electric motor will last much longer if it's ran for an extended period.

Interesting! If true, this implies that mine will last 700 years....20 mile commute duty.

[Alohaaaaa]

Originally Posted by galahad05

Interesting! If true, this implies that mine will last 700 years....20 mile commute duty.

Just look at buddies 200k 335. It lasted like 150k.

[Gizm0]

Originally Posted by galahad05

Interesting! If true, this implies that mine will last 700 years....20 mile commute duty.

It is true. I work with pump companies like KSB, Grundfos, Goulds, Flygt etc... given these are much larger (from a few HP to over 1000hp pumps) and they are used to pump drinking water, raw water and waste water but it's the same principle as the small electric pump in BMW engines. All the manufacturers give a maximum allowed number of starts per hour in order to avoid frying the motor too quickly. Typically for large pumps the limit is around 6 starts per hour.

[galahad05]

Originally Posted by Gizm0

It is true. I work with pump companies like KSB, Grundfos, Goulds, Flygt etc... given these are much larger (from a few HP to over 1000hp pumps) and they are used to pump drinking water, raw water and waste water but it's the same principle as the small electric pump in BMW engines. All the manufacturers give a maximum allowed number of starts per hour in order to avoid frying the motor too quickly. Typically for large pumps the limit is around 6 starts per hour.

This is very interesting info, thanks!

So....it's not quite so much how many times a day you start your engine, but how many times you start your engine while your water pump is hot I guess....

[techmaster05]

well it makes sense to me. im going on 90k right now and no pump failure so far

[techmaster05]

well it makes sense to me. im going on 90k right now and no pump failure so far

[mike3000fl]

I dont get what all the water pump hate is about.

Water pumps go out on all cars eventually. And if its driven by the timing belt, that can really mess things up if the pump seizes, smashing valves and bending rods on an interference engine. At the very least it is still a time consuming job to replaced because you have to get the timing of the cams aligned with the crank.

Yea, the e90 pump is a pain to get to, but at the same time, the thing is fairly simple to change once you know how to do it, quick release hoses, some clamps, and a few bolts.

Water pumps go out, on all cars, it's not some unique bmw thing. Most cars are going to call for it to be changed as preventative maintenance when the timing belt is changed.

[deeLow]

Originally Posted by techmaster05

well it makes sense to me. im going on 90k right now and no pump failure so far

Same here, 102k still original pump.

[floydarogers]

Originally Posted by mike3000fl

...Water pumps go out on all cars eventually. And if its driven by the timing belt, that can really mess things up if the pump seizes, smashing valves and bending rods on an interference engine. At the very least it is still a time consuming job to replaced because you have to get the timing of the cams aligned with the crank...

BMWs haven't had timing belts for 20 years, and they never drove water pumps. Don't know why you're talking about that ?

[mike3000fl]

Originally Posted by floydarogers

BMWs haven't had timing belts for 20 years, and they never drove water pumps. Don't know why you're talking about that ?

Reading is fundamental. I explained other cars have timing belts. Not bmws.


That's my whole point. We don't have to deal with timing belts or smashed valves. We just swap ours out. Few bolts and some clamps

[Eddien123]

It's not even that it's electric. Inside our pumps are plastic fins that push water through and they break off one by one. If you water pump goes bad it because of that.

[floydarogers]

Originally Posted by mike3000fl

Reading is fundamental. I explained other cars have timing belts. Not bmws.

No, you didn't explain that, please reread your post. And the subject of this thread is "E9x water pumps and thermostats", so I still don't understand your re-direction.

And the reason that people complain about BMW water pumps goes back to the M50 engine - the initial ones had plastic impellers that weren't adequate and would break and plug engine/other water passages. There were other (late '90s V8's) that had very poor cooling systems; pre-emptive changes at 60K miles or so was the only guarantee of not having serious problems. Also, many of the early plastic/aluminum radiators were junk.

[mike3000fl]

Originally Posted by floydarogers

No, you didn't explain that, please reread your post. And the subject of this thread is "E9x water pumps and thermostats", so I still don't understand your re-direction.

of course you don't understand, you are speshul.

I said that I don't get why people hate on the e90 water pump when all cars have them and some even require removal of the timing belt.

And the topic is actually "water pump lifespan", its up top ^ Talking about how most cars ask for WP replacement at timing belt change is relevant to topic. Keep on keeping on...

[Bmw_Crazy]

Originally Posted by mike3000fl

of course you don't understand, you are speshul.
...

[Efthreeoh]

Originally Posted by mike3000fl

I dont get what all the water pump hate is about.

Water pumps go out on all cars eventually. And if its driven by the timing belt, that can really mess things up if the pump seizes, smashing valves and bending rods on an interference engine. At the very least it is still a time consuming job to replaced because you have to get the timing of the cams aligned with the crank.

Yea, the e90 pump is a pain to get to, but at the same time, the thing is fairly simple to change once you know how to do it, quick release hoses, some clamps, and a few bolts.

Water pumps go out, on all cars, it's not some unique bmw thing. Most cars are going to call for it to be changed as preventative maintenance when the timing belt is changed.

Not flaming on your comments, and I agree with your position regarding belt driven pumps. Especially cam-belt driven pumps; it makes perfect sense to change the water pump when changing the belt because the majority of the cost of the job is in getting to the pump and when in there, changing the pump just adds 15 to the job. And belt driven pumps are inexpensive because there is a lot of competing manufacturers that build them aftermarket.

However, with an electric pump, none of the side-loading on the bearing and seals that eventually wears out a belt-driven pump are not present. Without those loads, one would expect the electric pump to last the lifetime of the vehicle (at least I did). The N5x pumps fail due to the electronics overheating, not a mechanical failure of the bearing, seals, or even the electric motor. Considering the N5x pumps are on the order of $500 part cost, it is a difficult proposition to make it a periodic maintenance requirement (as is a $65 belt driven pump). To me the design is a poor one. The motor control electronics should be mounted somewhere else than on the back of the pump motor sandwiched between the radiator and hot coolant (and near the turbos on a 335i). Better heat sinking of the motor controller would do wonders to pump longevity IMO.

[fun2drive]

328 uses a 200 watt DC motor and the 335 a 400 watt DC motor. Number of starts has little to do with the overall life. The environment does. Hot weather is hard on DC electric motors just as cold weather is. Add moisture to the mix from rain-snow-slush and you have a great opportunity to get a failed motor. Think where this motor sits right by the forward turbo. Think how well BMW has done on the oil filter housing gasket for example and you can get an idea that the suppliers for BMW are not up to the job because BMW mandated cost cutting.
I not seen a BMW water pump in the 6 cylinder since 1991 that will reliably go past 80K miles without failure. The mechanically driven ones usually had the bearings fail or the seal fail which many times caused the impeller to separate from the shaft. On the electric motors I have seen it looks like a lot of heat and water did the DC motor in but some failures because of the impeller too. Wish we has a better data on the failures of the water pump but BMW is on their 3rd revision and 2nd supplier of our water pumps.
In short BMW is trying to improve all these supplier provided components (HPFP-OFHG-Water Pump- etc) but keep cost inline. The HPFP failure is the best example followed by the water pump.
I carry a new pump and tstat for that faithful day since I am past 60K miles. I will replace mine when I hit 80K based purely on lack of confidence.
Seeing these failures shows why Consumer Reports has such a low opinion of the 335. The 328 also isn't a paragon of reliability.
Here is hoping BMW does get these component suppliers to up their reliability...

[Blackhawk36]

I replaced mine at 100k miles just as preventive maintenance. E90s in the states have the N51/52/54/55 engines. I think most of the E90 in Europe have 4 cylinders petrol and diesel. They have different pumps.