System Leak Test

WARNING: This page is about a different car, the 1996 Oldsmobile LSS, 1996 Oldsmobile Eighty-Eight, and 1996 Buick LeSabre. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: System leak test determines if a leak exists, and if leak is internal or external to compressor.

Install Pressure Gauge (J-22124-B ) and Attachment (J-22124-91 ) to air dryer and struts. See Fig 1 . With shutoff valve open, apply shop air pressure through service valve on pressure gauge until pressure gauge reaches 100 psi (7.0 kg/cm² ).
If air leak is indicated, close shutoff valve. This isolates compressor from rest of system. Check for drop in air pressure. If air pressure continues to drop, leak is external to compressor.
Test all connections using soapy water solution and repair as necessary. If air pressure stops decreasing after shutoff valve is closed, leak is in compressor assembly. See COMPRESSOR LEAK TEST under COMPONENT TESTING.
If air pressure increases rapidly but vehicle does not rise, check for pinched air line, and stuck or binding struts.

Fig 1: Checking System For Leakage

Courtesy of GENERAL MOTORS CORP.