FormerE30Owner

I believe that the 545's are mechanical water pumps - mine certainly is. 2005 545 MT6.

seanjordan20

Wow ok. I have an 05 530 (production 12/04) and it is an electric pump.

jtbgonesailing

My 05 530i M54, 1/05 production, the water pump is mechanical... Are you referring to the auxiliary water pump, by the heater valve, for rest heat and supplemental flow at idle, for the heater core?

seanjordan20

Correction on my end. The pump itself is ran by a pulley but the water system has an electric self bleeding procedure.

jtbgonesailing

Yea you can say that. By placing the heat setting to hottest and setting the fan speed to low, when you start the engine, both the mechanical pump and auxiliary pump circulate coolant to bleed any air pockets in the system.

The same procedure holds true for the 04-05 N62 in the 545i.

BraveHelios

So I finally had some time to replace the heater valve in my car and... I now have heat! I think anyway. It was a warm day (in the high 50's) so I can't tell if it is really fixed or if it is doing what it did before... I would get heat in warmer temps but no heat in colder temps (like 20's-40's). I'm gonna assume it is fixed but will let y'all know what it does in colder temps (here in Idaho... you know we ain't done with it yet!).

Also; my 545 (as do most) has has two water pumps... the main one which is mechanical, and the auxiliary, which is electric. I do not think my aux pump is bad though... I pulled codes on my car but did not find bad aux pump code; 9C77.

DanielFD

awsome. But no aux water pump error doesnt mean it isnt working. Mine failed without a code. Its worth getting tested as it runs when you turn on the heat in your car, and not only when you use the REST function.

BraveHelios

Good idea. I will do that asap.

BraveHelios

Update... not sure if I did this correctly but I I tested the electric aux water pump by removing the power connector to it and connecting 12 volts to the pump via a portable jump starter/battery pack. Nothing... no spark, no sound, no nothing. Does this mean my aux pump is dead? If so, any recommendations on where to buy one?

DanielFD

thats exactly how i tested mine. Obviously i tested my new part in the same way and it ran normally. Its around 160-180$ at the stealer i bought it used at 40$ from a breakers yard. This part rarely fails on its own so no need to go fork out too much cash.