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Mercedes heater controls 1988 420sel

I have intermiting heat. If I turn down the temp. I get cold air. Sometimes the car does not heat up and other time it does. If I donot move temp dial then it is fine. I have also smelled antifreeze but radiatior level is good. What is recirculation pump for climate control?



Thanks

Sounds like a bad mono valve. Don’t buy the whole replacement assembly, just buy the mono valve insert. This is a DIY repair that should take about 15 minutes.
Your car has an auxiliary pump on the firewall that keeps the coolant flowing when the car isn’t moving. The aux. pump is a known area of leaks.