Air Conditioning

The EPA has mandated a gradual phase out of Refrigerant 12 (R-12) due to fluorocarbons and their effects on the upper atmosphere. Prior to about 1995 almost all vehicles in the U.S. had air conditioner systems that used R-12 as the refrigerant media. Since the R-12 phase-out, the industry has used R-134A as an alternate refrigerant. Cars with systems designed for use of R-134A seem to cool well for several years. However, after a while, the systems seem to develop holes in the evaporator (the cooling coil inside the car) due to corrosion, particularly those evaporators made of aluminum.

Mercedes Benz was offering extended full or partial warranties for a while on these vehicles. A call to the dealer may be wise to check on the status of this program before having your conditioner unit repaired . We'd like to hear from you concerning the response.

Automobiles not having systems designed for R-134A but retrofitted due to system failure, tend to cool poorly at low speeds and at idle while the car is stopped when ambient temperatures exceed 90 F.This stems from the smaller condenser and evaporator sizes used for R-12. Operating pressures are also higher in the R-134A systems which can tax flexible hoses on R-12 designed vehicles.

Central Auto Care advises that R-12 be used in systems designed for R-12 as long as R-12 is obtainable ( which may not be much longer) even though the cost of R-12 is considerably more than R-134A.