Ford Workshop Service and Repair Manuals

The air cleaner is equipped with an air cleaner condition indicator.

The air cleaner condition indicator is a mechanical pressure gauge with a vacuum piston which acts as a display and indicates the condition of the air cleaner element.

The air cleaner condition indicator is mounted on the air cleaner, directly behind the air cleaner element.

It uses the available vacuum in the air intake system to continuously measure the air permeability of the air cleaner element.

The measurement of the air permeability of the air cleaner element is performed under full load, as this is when the maximum vacuum acts against the spring of the vacuum piston in the air cleaner condition indicator.

If the permeability of the air cleaner element is reduced, then the vacuum in the air intake system is increased, which pulls the vacuum piston down against the force of the spring under full load.

A mechanism above the vacuum piston immobilises it in this position.

If the permeability of the air cleaner element is reduced even further, then the vacuum increases again and the vacuum piston is pulled further down again.

The display on the indicator is divided into three areas with the following significance:

• Green zone - air cleaner element is OK.
• Clear zone - air cleaner element should be replaced.
• Red zone - air cleaner element must be replaced.

NOTE:Under the effects of extreme humidity it is possible for the air cleaner condition indicator to give an incorrect reading. If the air cleaner element has only recently been replaced, but the vacuum piston is in the clear zone or the red zone, then press the reset button. The air cleaner element does not need to be replaced.

After replacing the air cleaner element, the vacuum piston must be released by pressing the reset button, which returns it to its starting position.