Honda Accord/Civic/Prelude 1973-1983 Repair Guide

Positive Crankcase Ventilation (PCV)


The Honda is equipped with a Positive Crankcase Ventilation (PCV ) system in which blow-by gas is returned to the combustion chamber through the intake manifold and/or the air cleaner.


See Figure 1

  1. On 1973-75 models, squeeze the lower end of the drain tube and drain any oil or water which may have collected. Maintenance intervals are every 15,000 miles (1973-79 miles) and 60,000 miles (1980-83 models). On 1976-82 models, remove the tube, invert and drain it; after all condensation has been drained, reinstall it.
  3. Make sure that the intake manifold T-joint is clear. You first have to remove the air cleaner to where the joint is located. To clear the joint, pass the shank end of a drill of 0.9mm diameter through both ends (both orifices) of the joint.

Click image to see an enlarged view

Fig. Fig. 1: Typical PCV system component locations-1973 model shown

  1. Check for loose, disconnected or deteriorated tubes and replace if necessary. Make sure the hoses are clean inside, cleaning them with a safe solvent, if necessary. If the system has a condensation chamber attached to the bottom of the air cleaner, unscrew and remove the chamber, clean and replace it; when removing the top gasket from the chamber, note the angle of installation. Reinstall it in the same position to provide proper airflow.
  3. The 1983 models use a regular PCV valve. Check the valve by pulling it out of the valve cover with the engine idling. Cover the open end of the valve with your finger so airflow is stopped. If the valve clicks, it is OK; if not, replace it.

For further information on the servicing of Honda emission control components, check Emission Controls .