Author Topic: A/C and Heater battling it out...  (Read 4975 times)


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  • W116 Enthusiast
  • Location: Dallas, Texas USA
Re: A/C and Heater battling it out...
« Reply #15 on: 16 May 2019, 03:05 PM »
Excellent article and responses. Have this issue on my 350SE. The problem slowly got worse in a way my tech thinks is a valve vacuum problem: under heavy acceleration the heat would mysteriously come on overpowering the A/C for a few minutes. Now it is total air temperature war. My guy says M-B was very worried about hypothermia in the event of a system failure. My temporary fix is to tie off the heater valve arm (rt. side firewall location) to stop the war at least for the summer. 
1975 Euro 350SE
1992 Euro C124 300CE-24 Sportline 5-speed Getrag
2002 R170 SLK320 6-speed
1986 190E 2.3-16 - sold
1987 W126 300SDL -sold
1994 E420 - sold
1968 W108 250SE - sold
1962 W111 220Sb - sold
1969 Porsche 911T, 911S
1980 911SC
1974 Citroen DS23