[Rickfraz]

Hi all,

I have an 11 E350. I bought it 5 hrs ago with 45k miles on it. Almost from day one, the a/c will sporadically blow hot air in the summer. It would feel as if the heater was on. I always felt as if a sensor was malfunctioning but the dealer could never duplicate the problem. Friday on a business trip the ac went completely, even when I dropped the temp to LO it blew cool air. Today, the dealer told me I needed a new compressor but that was his guess until he could look at the car. I believe the compressor cycles because I can see white smoke

 

[bobs]

I had this happen on a much older car, but it may help anyway... I had a '97 that would do the exact same thing and it turned out to be a sticky duovalve. It sometimes refused to close all the way so it was letting hot coolant into the heater core when it wasn't supposed to. I had to open the hood and rap on it with a screwdriver to get it to behave.

 

[Rickfraz]

Thank you Bobs! Actually, a friend of mine mentioned the same thing about a year ago. I was traveling to Houston last year in February and temp was 25 outside, had hear set to about 75 and all of a sudden it got so hot that we had the set the temp to 63 just so it would get cool.

 

[Rickfraz]

My mechanic diagnosed the car, it read it’s a temperature sensor in the right footwell vent. The dealer calls it an evaporator temperature sensor. I googled it and it fits the description of what was causing my cooling woes the last 5 years. It cost $120. Mechanic also tried to recharge the system as he said it was very low so he pulled it out and was trying to put Freon back in the car but he said the car wouldn’t accept it due to the fault code that wouldn’t clear. He’s putting the part on tomorrow and hopefully my problem is solved but he cautioned that if this didn’t work it’s probably the compressor.

 

[Rickfraz]

My mechanic replaced the sensor and the car is now blowing snowballs, this is the message It codes.