Nissan/Datsun 200SX/510/610/710/810/Maxima 1973-1984 Repair Guide

Positive Crankcase Ventilation Valve



Gasoline Engines

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Fig. Fig. 1 Cutaway view of a PCV system-1980-81 510 (except Canada)

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Fig. Fig. 2 Cutaway view of a PCV system-610 and 710, 1978-79 510 (all),1980 510 (Canada)

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Fig. Fig. 3 Cutaway view of a PCV system-810, Maxima and 1980-81 200SX

This valve feeds crankcase blow-by gases into the intake manifold to be burned with the normal air/fuel mixture. The PCV valve should be replaced every 24,000 miles on models through 1979. On 1980 and later models, no strict interval for maintenance is specified. However, it is wise to check the system occasionally in case of clogging, especially if you know that you have a vehicle that has been neglected. Make sure that all PCV connections are tight. Check that the connecting hoses are clear and not clogged. Replace any brittle or broken hoses.

To check the valve's operation, remove the valve's ventilation hose with the engine idling. If the valve is working, a hissing noise will be heard as air passes through the valve, and a strong vacuum will be felt when you place a finger over the valve opening.

The PCV valve is located in the side or bottom of the intake manifold.

  1. Squeeze the hose clamp with pliers and remove the hose.
  3. Using a wrench, unscrew the PCV valve and remove the valve.
  5. Disconnect the ventilation hoses and flush with solvent.
  7. Install the new PCV valve and replace the hoses and clamp.

Diesel Engines

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Fig. Fig. 4 Cutaway view of a diesel crankcase emission control system

These engines use a crankcase emission control valve in place of the PCV valve. Although different in configuration it is similar in function.

To replace the valve which is located inline between the cylinder head cover and the intake manifold:

  1. Locate the valve. There should be three hoses attached to it.
  3. Use a pair of pliers and squeeze the hose clamp on each hose so that you can remove the hose from the valve.
  5. Install the new valve and reconnect all the hoses.