ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Air Compressor Will Not Pump Air

Air governor is malfunctioning or not set correctly

Check the air governor for correct operation. Refer to
Procedure 012-016 (Air Governor) in Section 12 and the OEM service manual.

Unloader valve is malfunctioning

Check the unloader valve and unloader body seal. Refer to
Procedure 012-014 (Air Compressor) in Section 12 and the OEM service manual.

Air compressor intake or exhaust valve leaks air

Inspect the air compressor intake and exhaust valve assemblies. Refer to
Procedure 012-007 (Air Compressor Cylinder Head, Single Cylinder) in Section 12. If the air compressor head is
not serviceable, replace the air compressor head.
Refer to Procedure 012-014 (Air Compressor) in Section 12.

Splined drive coupling or gear is excessively worn

Check the coupling for wear. Refer to
Procedure 012-014 (Air Compressor) in Section 12.

Air compressor is excessively worn or internally damaged

Replace or rebuild the air compressor. Refer to
Procedure 012-014 (Air Compressor) in Section 12.