I have a silly question, I want to replace the water pump and I don't want to drain the coolant, I know some will come out from the engine block and it will be a mess.

Is there any problem with this? What can get damaged?

Thanks,

David

No problem. Just wash off the front of the engine with water after the coolant dumps out.

It'll still drain most of the coolant in your radiator.
Your laziness is astounding.
If you're being frugal just reuse the old coolant but it's much better to change it.

Skip the BMW stuff and get Motul concentrate. www.motorspot.com (http://www.motorspot.com)
Or look into G-05 or G-12 coolant, one of those should work fine.

Thanks, guys.

Yes, I try hard to be lazy, lol.

So I will need to do a full refill? Damn it!

The thing is that I want to put my old plastic pump on the car, take the composite one, see how it failed exactly and then see what I will do (get the composite one rebuilt or get a new one).

As I'm doing this job twice, I want to do it as easy as possible.

What makes you think the composite pump has failed? The reason BMW went to a pump with a composite impeller was to avoid impeller failure. Bearing or seal failure is possible, but that results in a specific set of symptoms.

What makes you think the composite pump has failed? The reason BMW went to a pump with a composite impeller was to avoid impeller failure. Bearing or seal failure is possible, but that results in a specific set of symptoms.
Bearing failure and shaft play, at least that's what the shop that rebuilt my alt told me. It's making a lot of noise.

Bearing failure on a waterpump is easy to check without removing the pump. Pull the belt and see if there's any sign of roughness or loosness in the shaft. If there is the bearings are toast and the pump needs to be replaced immediately.

Bearing failure on a waterpump is easy to check without removing the pump. Pull the belt and see if there's any sign of roughness or loosness in the shaft. If there is the bearings are toast and the pump needs to be replaced immediately.
Yeah but I don't know what to replace it with, the plastic pump is supposed to be junk and the composite one failed too damn quickly IMO.

The early plastic impeller pumps were known for impeller failure, but the later composite impeller pumps don't have that problem. Nor have I heard of early bearing failure problems with the newer pumps. Maybe you just got one that was doomed from the start (this was a BMW OE pump, right?).

I thought the "composite" pumps were plastic. Composite typically means a type of plastic or synthetic material, not metal.
Are these "composites" sold by BMW metal?

The early plastic impeller pumps were known for impeller failure, but the later composite impeller pumps don't have that problem. Nor have I heard of early bearing failure problems with the newer pumps. Maybe you just got one that was doomed from the start (this was a BMW OE pump, right?).
It's OEM, I bought it at a store that sells BMW OEM parts. It's made in Germany and it's the same brand that makes the OE parts.

I know, I should have got the OE anyways (there wasn't a big difference in the price).

Sounds like your pump failed prematurely, but failed in the good-old-fashioned way waterpumps fail on all cars: bearing failure... I doubt it has anything to do with the composite/metal/plastic issue...

[QUOTE][I thought the "composite" pumps were plastic. Composite typically means a type of plastic or synthetic material, not metal.
Are these "composites" sold by BMW metal?/QUOTE]
Composite means two or more materials are combined. The early plastic impeller pumps that have a history of impeller failure were (as far as I know) a simple plastic material. Later pumps use a different plastic and have at least one other filler incorporated in the impeller, hence the term composite impeller.

Sounds like your pump failed prematurely, but failed in the good-old-fashioned way waterpumps fail on all cars: bearing failure... I doubt it has anything to do with the composite/metal/plastic issue...
Is there any chance it can be repaired?

I'm not trying to be cheap but if a new one failed this quickly, I'd rather have a good shop rebuilt this one (we have shops that rebuild pumps here) and end up with a bullet proof waterpump (probabily this will cost me more than a new one).