Shon

With P0128, P112B codes and 91k miles, I decided to do the cooling system overhaul today.

Replaced water pump, thermostat, expansion tank, belt and coolant of course. This is what came out of the car instead of the blue BMW coolant, somea cheap Autozone coolant or brewed coolant after 91k miles. No wonder the codes and no heat.



Few tips:
1> Buy a 10mm ratcheting wrench for the last bolt of water pump behind main pulley. No need to remove the fan or touch the main pulley for that bolt. Once the bolt is completely loose, angle the waterpump housing down towards passenger side and the bolt will come out. To reinstall, put the bolt in the water pump and angle it upwards so the bolt can sit in the groove.

2> To drain the block, remove the silver support plate, loosen the driver side subframe bolt about half way and unbolt the fender liner to get access to the drain bolt. Putting it back is a different animal, words can't describe the agony.

On the side note, I have no idea how to remove the small accessory belt from main pulley. There was no tensioner pulley. The belt wraps around the main pulley and something else, assuming it's the AC pump.

twh

Was it at all foamy? Like a melted down chocolate milkshake? That indicates oil mixed in with the coolant.

Shon

It wasnt foamy but was Dark Brown, almost the color of new engine oil but tad bit darker. Whats the cause of oil mixing?

twh

That would be from a failed head gasket or leaking oil cooler or leaking transmission oil cooler. When small amount of oil enter the cooling system and mix in they create this. Here is a Google on images. Take a look at the ones with brown stuff...this is what I am taking about.

https://www.google.com/search?q=oil+...=isch&imgdii=_

Booyaazaa

Damn that doesn't look good.