Is you car overheating even at a low engine speed? Does the engine temperature drop when you accelerate? Well, those are signs of a faulty water pump. But don’t worry, in this DIY I’ll be showing you how to replace your water pump. Let’s start!
Tip: be sure to work with a cool engine, and I highly recommend wearing eye protection.
BMW E-46 1998-2006
Drain the cooling system and Remove the cooling fan shroud. You can take a look at our articles referring to them.
(Link to flushing coolant article)
(Link to Cooling fan replacement)
Loosen the four 10mm water pump pulley fasteners. Loosen your fasteners but do not remove them completely, then remove the engine drive belt but don’t remove the water pump pulley fasteners yet.
You can take a look at our Replace Driver Belt article for guidance (link)
Now, remove four 10mm water pump pulley fasteners.
When the pulley is off, inspect for any cracks or damages then remove the four 10mm water pump pulley fasteners .
You can do this by threading two M6 bolts into the sides of the water pump. Use the ratchet to tighten them by doing a few turns per side then switching and doing the same to the opposite side, repeat until the water pump o-ring has cleared the timing cover.
surface and check for any debris inside the water pump cavity. Lubricate the water pump o-ring with the coolant.
Install it into the timing cover, then tighten the four 10mm water pump mounting nuts. Torque the four nuts in a criss-cross pattern to specs.
Then install the water pump pulley and torque the four 10mm water pump pulley fasteners in a cross pattern.
And finally, reconnect everything back in reverse order then refill the coolant and bleed system. And you’re done!