[Adrianmateos]

Yes hi I have a 2009 BMW 328I no mods just a regular commune car the water pump has gone bad and I need to replace it my question is do I have to replace the thermostat as well believe that the thermostat is in good condition

[ryan stewart]

Honestly I would do the stat and the hoses that touch both just because its such a PITA to get in there you wouldnt want to have to do it again, or at least I wouldn't.

For me it was actually much easier to just unhook the hose from the engine, the 4 way, and then remove the entire thing as an assembly. Then built the new "assembly" on my bench and slid that one back in.

[Adrianmateos]

Ok great thaaks.

[fravel]

I'll echo that - you have to remove the thermostat to take off the water pump anyways. Add in the extra hassle of draining/refilling/bleeding coolant, it makes sense to just replace the thermostat while you're there.

[mainbearing]

Definitely the thermostat and water pump together. The hoses idea is great. You might want to change out the hose with the coolant flange to the oil filter housing too, and the upper radiator hose.

The plastic flanges on those age and deteriorate. An aluminum one with hose is also available for the oil filter housing one.

I used a Behr thermostat, as some said the Whaler one has leak problems. And I used an OEM Pierburg pump. The pump was unreliable and BMW moved away from it with the B58 engine I heard.

[Adrianmateos]

Thanks a lot everyone I will Definitely be doing water pump and thermostat and going over all the hoses just so there’s no leakage I really appreciate everyone’s comments and help