BMW Repair: Climate Control--95 BMW 740i, radiator coolant, heater coils

Question
I just bought this car two weeks ago so I dont know much about  the history.  95 BMW 740i.  The first day I had it the A/C quit blowing cold.  The old owner is a jerk and won't tell me anything about the car other than I bought it and it's mine.  He did take it in for A/C service in September as there is a yellow sticker on the front of the engine compartment stating that they injected some dye into the system to check for a freon leak.  He said it was fixed but I don't think this is the problem.  I read some of the other help suggestions and turned the temperature up all the way to 90 degrees...same thing.  The car just blows outside air.  Doesn't get cold with the A/C (snowflake) button pushed and doesn't get hot with the temp turned all the way up.  It just blows air at a constant lukewarm temp.  I've tried turning the a/c button off and on.  Checked the various vent controls and made sure the compressor is working (which I think it is).  The one thing that struck me wierd is the distinct smell of radiator coolant when I switch from a/c on to vent.  I was hoping for a leak so I could just replace a hose or buy the R134a with the sealant.  

Sam

Answer
Hi Sam!
You are talking of three possible problems here:
a) smelling coolant at vent either means your radiator is spewing large amounts of coolant to be smelled right into the car (which I do not suppose), or your evaporator heater coils are leaking coolant. You could probably test for this by running the engine and the heater and looking beneath the car to see if the evaporator is dripping coolant at approximately the area of the firewall/bulkhead and the transmission. Also look behind the dashboard at the left side of the firewall where the heated water hoses join the evaporator heater coils (inside the engine compartment).
b) the AC not cooling could be any of the usual AC problems
like no freon due to a leak, compressor not working, filter clogged, expansion valve defective, switch not switching on the clutch of the compressor, etc.
c) heater not working could be due to a bad switch, bad heater valve, bad secondary water pump, air inside the radiator/cooling system, bad flaps, etc.
To sum it up, the old owner really is a jerk for not even giving you a brief history of your AC/heater problems. Considering the severity of your problem, I would suggest that you bring it to an aircon shop. It could be any aircon shop, since your car's aircon system is IHKR which is the manual aircon type.
Tino