Heaters

[Nickskip]

My heater blows cold if selector knob turned as far as possible to the blue (anti clockwise) if I turn it a fraction clockwise it blows max hot. Air con working and engine temp normal, any ideas? Thanks Nick

 

[IainP]

Mine was a bit like that, though not quite as bad, the actuator on the back had come out of the guide rail. 30 sec fix, but you have to remove the console to gain access.

 

[NZ00Z3]

Yes, it does sound like the temp control knob has a problem.

• With the temp control knob fully anticlockwise, it turns off the hot water valve that feeds the heater.
• As you turn the knob more clockwise, the hot water valve is turn on (its either on or off) and the knob adjusts the air blend flap. The more clockwise you turn it, the more the air passes though the heater matrix.

Sometimes the leaver/actuator on the back of the knob comes off and you "click" it back into place. Other times the small plastic nub on the lever breaks off and you have to replace it with a metal screw or model airplane ball joint. See: https://www.bimmerfest.com/threads/z3-problem-temp-control-issue.318432/page-3#post-8014240

The route cause is the old foam seal gasket on the blend door degrading and sticking when in the fully cold position. The force to break the door open, breaks the plastic nub or pops the lever out of place. See this thread on adjusting the blend door. It's just too hard to get in and sort the old foam gasket. Post #119 https://zroadster.org/threads/brrrrrrrr-its-cold-in-here.5667/page-6

 

[IainP]

With mine, it was one of the previous owners just using brute force on everything, once I popped it back in place it worked perfectly. Wish I could say the same about some of the switchgear he/she/they mangled.