FLUSHING A/C SYSTEM
There is considerable controversy over the question of whether or not to flush A/C systems or how to go about it. Before CFCs were classified as harmful to the environment, it was a common practice to open flush contaminants from a system. The waste fluid was vented to the atmosphere. This practice is now ILLEGAL and can no longer be used.
Most OEMs don't recommend A/C system flushing. They recommend replacing the defective component and installing a liquid line (in-line)filter ahead of the expansion valve or orifice tube. Ford Motor Company is one exception to this rule.
Note. DO NOT flush accumulator/receiver-drier, muffler, hoses and thermal expansion valve/fixed orifice tube as residual flushing agent cannot be completely removed from these components. These components are generally replaced after A/C system contamination. Hoses can be reused, unless they are clogged with debris. Only flush evaporator core and condenser core, and metal inlet and outlet lines.
- Manufacturer recommends flushing contaminated system using one gallon of Ford A/C System Flushing Solvent (F4AZ-19579-A), a Filter (FL-1A), an A/C Flusher Fitting Kit (014-00992). DO NOT reuse flushing solvent and filter, they are intended to be used on one vehicle only.
- Discharge A/C system, using approved refrigerant recovery/recycling equipment. Flush specified A/C components using A/C System Flusher (014-00991), according to manufacturer's operating instructions.
- If an A/C system flusher is not available to clean A/C system, an in-line filter kit can be used. Filter kit is installed before replacement compressor, accumulator/receiver-drier, muffler, and thermal expansion valve/fixed orifice tube have been installed.
- Filter kits are used with either a rubber lined suction hose or with a nylon lined suction hose located between compressor and evaporator. Rubber lined hose has a wall thickness of 1/4" and nylon lined hose has a wall thickness of 1/8". (Scheme 8)
- The filter kit for either type hose has 2 filters. A temporary pancake filter and a permanent in-line suction filter. Pancake filter is temporarily installed between condenser and condenser-to-evaporator line. (Scheme 9) Permanent filter is installed in suction line between accumulator and compressor.
- Install replacement components (compressor, accumulator and fixed orifice) with correct amount of NEW refrigerant oil. See A/C COMPRESSOR REFRIGERANT OIL CHECKING article.
- Cut suction hose between compressor and accumulator (closer to compressor). Remove a length of suction hose to accommodate suction filter. Measure side wall of suction hose and install appropriate filter with NEW "O" rings and filter clamps. If side wall is 1/4", use in-line filter labeled USE WITH RUBBER INNER LINED HOSE. If side wall is 1/8", use in-line filter labeled USE WITH NYLON INNER LINED HOSE. Ensure arrow on filter is pointing in direction of refrigerant flow. Tighten hose clamps to 54 INCH lbs. (6 N.m). (Scheme 8)
- Install pancake filter in liquid line between condenser and condenser-to-evaporator line. Ensure filter inlet (label) is toward condenser. Evacuate, charge and leak test A/C system. See the following: «EVACUATING A/C SYSTEM»(ref-125202-S20790938952001100400000). «LEAK TESTING»(ref-125202-S08359116282001100400000). «CHARGING A/C SYSTEM»(ref-125202-S38619380682001100400000). Check NEW filters and hoses for clearance from other engine components. Use tie straps if necessary.
- Place a fan in front of radiator. Select MAX A/C operation and set blower motor speed to maximum. Start engine and allow to idle. Ensure A/C is operating properly. Slowly increase engine speed to 800 RPM, then 1000 RPM, and then to 1200 RPM. With engine speed set to 1200 RPM, operate engine for one hour with A/C system operating.
- Stop engine. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove pancake filter, hoses and fittings. Discard pancake filter. Reconnect liquid line, evacuate, charge, and leak test A/C system. See the following: «EVACUATING A/C SYSTEM»(ref-125202-S20790938952001100400000). «LEAK TESTING»(ref-125202-S08359116282001100400000). «CHARGING A/C SYSTEM»(ref-125202-S38619380682001100400000). Ensure A/C system is operating properly.
