My 190E A/C runs warmish in slow traffic. In fact, here in Texas it becomes unbeareable in the Summer. The air turns cold once I drive at high speed for several minutes. Is there a problem with my A/C, or it's just the way it works in 190E?

I expect that it is slightly low on freon.

Have a great day,

The condensor relies on the aux. fan for cooling at low vehicle speeds. Make sure your condensor is clean and your aux. fan kicks in at the appropriate P/T point (~52* with the red switch on receiver/dryer). If you have access to ref. gauages post the high and low side pressures at 1500rpm. and we might be able to tell more. Mercedes has a reputation in A/C circles for being "condensor challenged", but it shouldn't be "unbearable". R-12 or R-134a

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Mine definitely puts out warmer (but still cool) air when I'm not moving, despite the aux fans being on. The output air is, however, considerably cooler since I got the aux fans to work (had a bad resistor).

You can fairly simply check your low-speed aux fan operation by letting the car idle with AC on on a hot day. The fans should eventually come on at low speed, once the pressure in the system is high enough, unless it's low on charge (or there is a problem in the aux fan circuit).

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Steve
'93 400E

I'm having the same problem with my 1989 300SE. The system hasn't been charged in 5+ years and I'm wondering if a low freon condition will cause this problem as well? (independent of the aux fan)

Thank you.

George

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2004 E320 Wagon
1989 300SE
1998 Range Rover 4.0 SE

Thank you for the suggestions everyone. I will have the freon level checked. I don't think the previous owner attended to the A/C for a while since I don't find any records on it.

Pardon my ignorance, but where is the condensor located? And what does the frase (~52* with the red switch on receiver/dryer) mean? I am not sure what switch we are talking about and where that receiver/dryer is.

The car is 1990.

Thank you.