Just to reconfirm, to bypass the heater core on a 89 535i E34 model I simply use a plastic "T" an connect hoses 2 & 3 to the horizontal on the tee and hose 1 to the vertical on the tee.
Hose 2--|--Hose 3
|
|
Hose 1
Hoses #2 & #3 are the coolant-in and hose #1 is coolant-out (return).
Thanks.
Ferret,
As per the diagram, I thought that I would "T"-connect hoses #21 and #22 to hose #23
Hoses 21 and 22 are water-in and hose #23 in water-out so that would by-pass
the heater core.
Please correct me if I'm wrong before I start the work.
Thanks..
leave your heater control(s) on cold,to make sure turn the drivers dial all the way past the "click" on coldest position
Gone but not forgotten