Does it do the same thing when the engine is still warming up? (temperature gauge not rising yet)
When you turn on heating only when the engine is already hot, does the heating work immediately? (slow reaction could mean low coolant, blockage, or air in cooling system)
Do you get much heat out of your dash vents when you turn the heating on when the engine is still cold? (this is when the condenser bypass should be active)
I am asking all this to get an idea whether the condenser bypass is working properly. In the diesel cars the coolant water only slowly warms up, and cabin heating is boosted by electric heaters in the vents as well as by flowing hot compressed refrigerant through the cabin heat exchanger and dumping its heat there instead of in the the condenser in the front of the car, I am trying out work out if the recirculation setting is somehow activating the bypass.
I only became aware of this system this year, and I do not know the exact mechanism the cooling system uses to sense when the coolant is warm enough to deactivate the condenser bypass.
You could probably test if your problem has something to do with the bypass mechanism by temporarily disconnecting the wires to the bypass mechanism at the lower right (looking forward) side of the radiator, and see if the problem goes away. If it doen't, the problem is something else. I don't know if the default is open or shut though. I am ***uming the default is bypass = off.
