roadmax

Out with the old and in with the new part. I'm keeping the old one in case I need will repair it with brass Y adapter.





photohosting

anthracite

I just had to add around a quart to mine as well. Replaced the water pump last August 2017. I'm going to start looking for a leak this weekend. I think it's the coolant overflow cap as it had a lot of residue on it.

Steve

roadmax

How did you determine the water pump needs replacement?

audiophool

Well, sometimes they leak, other times the bearing wears out. Buddy had an M62 that looked like this:

anthracite

It stopped working and my car overheated. Thankfully I was able to pull over before it got too hot. The CEL came on and the warning displayed. I also had the codes that the water pump wasn't working (circuit not complete or something like that). It only had 56K miles on it too. UGH.

Steve K.

roadmax

I have 122K and not sure if it needs replacement or how to check for signs that replacement is required.
It is kind of risky to wait until it fails.

audiophool

Your 550 has a belt-driven wasserpump. 535s have electric ones that can fail without warning. The 550 pump can fail as I showed in the video, but that's pretty extreme. Even with this much play, my buddy's car wasn't losing much if any coolant, just making a horrible racket. But once I had the belt tension off, it pissed out all its coolant whilst parked overnight.

You can take the belt tension off using a big Torx (make sure it's the correct size and fully seated in the recess before applying force), then spin the pump to check for play and noise. If it's leaking you'll see crusty residue either white or the colour of your antifreeze mix (blue?).

roadmax

1.Just got torx bit set, I think T55 or T60 will be the one. Is it clockwise push to release the belt tensioner?

2.So far I'm only noticing a very small dry blue residue along a line where water pump is mounted on engine block, no leak only small thin line residue, this would be an indication that gasket needs replacement.
If I do not notice any issues after releasing belt tensioner, would it be a good idea replacing the gasket only?

3.What about thermostat, how risky is if they fail, what are the signs of replacement required?

Took pictures of small residue:
fallout facts
screen shot on windows

audiophool

That seepage looks pretty minor, and I'm not sure if it's enough to be worrying about. With the correct Torx bit (T60 IIRC), use a breaker bar rather than a rachet. You'll know quickly by feel which way to push. Make note of the belt routing. Once you have the belt off, you can see if there's any play in the pump. Removing the water pump pulley should allow you to inspect whether there is any leakage through the bearing.

There's a nice tutorial for the belt here: https://www.pelicanparts.com/techart...eplacement.htm

If you're in for R&R of the water pump/thermostat you can take care of it all at once, but there are a number of other parts I would change at the same time:
-water pump/thermostat
-transfer tube 3
-upper/lower rad hoses (large ones)
-accessory drive belts
-tensioner
-idler (deflection) pulley
-coolant bleed line between upper rad and expansion tank (these have a plastic section in the middle that gets very brittle)

The water pump uses a 'profile gasket' to seal it to the front cover, and there are transfer pipes that connect to the assembly. When removing, you must ensure that pipes 1 and 4 stay seated on the engine side. Pipe 3 appears to be where your seepage is.

RealOEM.com - Online BMW Parts Catalog

RealOEM.com - Online BMW Parts Catalog

roadmax

I will go over more details later but just to clarify there is no seepage at pipe 3 (both small and large pipes are bone dry), the seepage shown in pictures is where profile gasket 2 is mounted.
So my question is if water pump still shows OK results after inspection (removing the belt), would it be better to only replace the profile gasket 2?