On vehicles which exhibit repeated orifice tube plugging, or when a compressor is being replaced due to internal causes an in-line filter should be installed. As stated in Dealer Technical Bulletin 90-T-11 (Corporation No. 931203R), General Motors recommends liquid line filters as they eliminate the need to use CFC-11 to flush the A/C system during repair service.
Two types of filters are available to service the 1985-90 Ninety-Eight and Eighty-Eight models and are described as follows:
In-line filter for vehicles with one piece liquid line from the condenser to evaporator (See Figure 1 on page 4 of this bulletin). This filter is a splice-in" design so the existing liquid line can be used. This type is available with or without an orifice tube built in.
In-line filter for vehicles with a two piece liquid line from the condenser to the evaporator (See Figure 2 on page 4 of this bulletin). This tube with filter is a direct replacement for the existing rear half (evaporator side) of the liquid line. The orifice must be removed when using this type.
To install the splice-in filter, the following procedure should be followed after the A/C system has been discharged for the repair.
1. Remove proper amount of tubing:
Filter without orifice - 2 inches Filter with orifice - 2.75 inches
Cut end of tube square with sharp tubing cutter.
Remove external burr with file. Carefully cut out internal burr so that shavings do not drop into tubing. Prior to cutting the internal burr from fixed vertical tubes, wedge a small cloth ball into the tube. Loose particles are swept away as the cloth is removed. High side particles may be caught in the drier screen or the expansion device screen. Under no circumstances should foreign material enter the low side plumbing.
2. Place the nut over the tubing. Then install the ferrule with the small end toward this nut. Do not install "O" ring.
3. Push tube into fitting, bottoming it out while the nut is securely tightened 15 N.m (11 lbs. ft.).
4. Disassemble the joint. Lubricate the "O" ring with clean 525 viscosity refrigeration oil. Install "O" ring on tube. Reassemble and tighten 15 N.m (11 lbs. ft.).
To install the tube with filter, (see Figure 2) the following procedure should be followed after the A/C system is discharged for the repair.
1. Remove engine compartment splash panel at cowl to access fitting to accumulator.
2. Remove windshield washer reservoir or coolant reservoir as necessary to access lower A/C fitting at orifice tube.
3. Disconnect A/C fitting at orifice tube and remove orifice.
4. Disconnect A/C fitting at evaporator inlet.
5. Remove the rear half of the A/C liquid line from vehicle.
6. Install the tube with filter and align filter lines to match up with A/C fittings on vehicle and tighten fittings on filter. Install new "O" ring and torque fittings to specification, 15 N.m (11 lbs. ft.) (This step is not necessary on some Tube with Filter designs.)
7. Tighten lower A/C fitting on liquid line to specification, 24 N.m (17 lb.ft.).
8. Tighten A/C fitting at evaporator inlet to specification, 24 N.m (17 lb.ft.).
9. Reinstall windshield washer reservoir or coolant reservoir removed in Step 2.
10. Install engine compartment splash panel removed in Step 1.
Part numbers are as follows:
Splice in type filter for vehicles with one piece liquid line.
52450767 Filter without Orifice 52450924 Filter with Orifice
The filter without orifice tube is preferred if there is suff icient space to allow installation.
Tube with filter for vehicles with two piece liquid lines.
This tube with filter replaces the rear half of the liquid line. The original orifice is removed as the tube with filter has a built-in orifice.
25533642 For 1989 or 1990 Vehicles 25532892 For 1988 Vehicles
Parts are currently available from GMSPO.
Filter installation should be used as an add condition to either:
D3200 Expansion Tube - Replace D4440 Compressor Assembly - Replace
For 1985-1987, put the appropriate filter installation time (0.4 hrs.) in the other labor hours column as no add is provided in the Labor Time Guide.
For 1988-1990, use the appropriate add condition as listed in the Labor Time Guide.
Labor Time for Splice in Filter: 0.4 hrs. Labor Time for Tube with Filter: 0.3 hrs.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.