In my never ending quest to repair my Euro (non ACC) climate control I again purchased Mono-valve Inserts online. I had replaced these Bosch inserts three years ago, but to my surprise the rubber diaphragms recently died. Unlike the last ones that were Bosch, the brand I received in the mail unknowingly was Ronak. I installed them only to find out that the heating problem did not really go away - Not thinking there would be any fault with new inserts I started some major and sometimes painful investigating elsewhere. In the process I first cleaned and then replaced the Valve itself with a salvaged unit, took out and repaired the Aux. Water Pump and learned about Electrical Pulses and temperature selector wheels more than I ever intended too. With help from many members here.
I have now come full circle to believe that perhaps I got what I paid for - A less expensive but no good insert. The Ronak insert is definitely ever so slightly shorter than than the Bosch, though perhaps that has no meaning. Before I go buying more inserts and making these assumptions and accusations I was wondering if people here have good experience with after market brands, or does every one stick with Bosch which is much more expensive.
Still hoping to find a cure...

1987 300SE Euro
These are two earlier threads where I tried to figure things out -

126 Mono/Duovalve again...
Can the 126 Monovalve Leak ? (Not the Insert).