Hi All,
What is the proper way to drain the coolant competely off the system? Last week I had my coolant tank cracked and I I ordered replacement tank and cap. Meanwhile would like to know where all the drain plugs are located on E61 535i.

TIS tells to unplug the lower radiator hose and thats it. How about the coolant in the engine block?

thanks

 

It depends on how deep you want to go. I wanted to get into the block but that wasn't possible without either pulling the exhaust manifolds (I have an 07 3L NA) for above access above or water pump, etc from below. With the steering rack plus half shaft and subframe, it still took quite the concoction of u-joint sockets to get the water pump hose loose in order to drain most of the water. Can't say I'd do it again.
I suppose you could activate a bleed cycle (like you do after filling the system back up) but that's long and I would worry about burning the pump out without coolant. Could also just supply 12V to the two pins [I think] but would have to look at a wiring diagram to make sure there wasn't anything else needed or issues caused by that.
Honestly, I wouldn't mess with it - just pull the hose off the rad and front of the water pump. With a regular drain interval (~2 years) you'll keep the chemistry replenished enough to be fine.

Andy
07 530xit 6MT

 

Thanks Andy, will try to keep it simple. BTW, does anyone have experience with these?