GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Air Cleaner


See Figure 1

The air cleaner has a dual purpose. It not only filters the air going to the carburetor or throttle body (as equipped), but also acts as a flame arrester if the engine should backfire. The engine should never be run without the air cleaner installed unless an engine maintenance procedure specifically requires the temporary removal of the air cleaner. Operating a vehicle without its air cleaner results in some throaty sounds from the engine giving the impression of increased power but will only cause trouble. Unfiltered air to the carburetor will eventually result in a dirty, inefficient carburetor and engine. A dirty carburetor increases the chances of carburetor backfire and, without the protection of an air cleaner, an underhood fire becomes a very real danger.

Click image to see an enlarged view

Fig. Fig. 1: Exploded view of a common early model Thermostatic Air Cleaner (THERMAC) assembly

Your truck is equipped with an air cleaner element of the paper cartridge type. The element should be replaced every year or 30,000 miles, whichever comes first. If the truck is operated in heavy traffic or under dusty conditions, replace the element at more frequent intervals.


See Figures 2, 3 and 4

For most vehicles, the filter element is easily accessible by removing the cover from the air cleaner assembly.

  1. Loosen the wing nut(s) at the center of the air cleaner cover, and/or release all of the clamp fasteners along the cover's edge.

Vehicles equipped with MFI-Turbo or CMFI motors use an air cleaner housing which is mounted remotely from the throttle body (unlike carbureted or TBI motors whose housing sits on top of the unit). On these vehicles, follow the air snorkel back from the engine to locate the housing. It may be necessary to disconnect one or more of the air hoses from the housing before removing the filter.

  1. Remove the cover from the air cleaner assembly, then remove the air cleaner element from the housing.
  3. If necessary, disconnect the air intake hose, and, if applicable, the heat stove and/or vacuum line(s), from the air cleaner housing, then remove the housing from the vehicle.

To install: