Vehicle is a well maintained '91 300-SEL. 60k miles. A/C compressor cycles on/off about every 10-15 secs. I saw a similar post the other night; some mention was made in that case about the high pressure side running above spec. Does this imply excess R-12? Thanks for your time.

Mike Murrell

Overcharging is one possibility.
If the high press switch is cycling it.
Cooling fan coupling or Aux fans n/o .
Intermittant O\C in electrical path to the compresser.
Bugs and crud between condensor and radiator.

Usually when the compressor is "short cycling" like you described, the system is low on refrigerant.

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in
Mercedes automobiles

Or I have seen many that the pressures were too high because the auxillary fan fuse is blown, if so go up by 5 amps.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
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