Volkswagen Air-Cooled 1970-1981 Repair Guide

Air Injection System 1973-74


See Figures 1, 2 and 3

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Fig. Fig. 1: Air injection (exhaust manifold afterburning) system-1973 Type 2/1700 models

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Fig. Fig. 2: Air injection (exhaust manifold afterburning) system-1974 Type 2/1800 models

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Fig. Fig. 3: Exploded view of the Type 2 air pump filter unit

Type 2 vehicles are equipped with the air injection system, or air pump as it is sometimes called. In this system, an engine driven air pump delivers fresh air to the engine exhaust ports. The additional air is used to promote after-burning of any unburned mixture as it leaves the combustion chamber. In addition, the system supplies fresh air to the intake manifold during gear changes to provide more complete combustion of the air/fuel mixture.

Check the air pump belt tension and examine the hoses for deterioration as a regular part of your tune-up procedure.


The only maintenance required for the system is an air pump belt tension check at 6,000 mile intervals and an air pump filter

element replacement at 18,000 mile or 2 year intervals. Refer to General Information And Maintenance for the belt tension check.

The air pump filter element is located in a housing adjacent to the pump. To remove the element, loosen the hose clamp and disconnect the filter housing from the pump. Then, loosen the wing nut and draw out the element. Never attempt to clean the old element. Install a new paper element and assemble the filter housing.