Ford Thunderbird/Cougar 1983-1997 Repair Guide

PCV Valve


The PCV valve system vents combustion blow-by gases from the crankcase into the engine air intake where they are burned with the fuel and air mixture. The PCV valve system helps to keep the engine oil clean by ridding the crankcase of moisture and corrosive fumes. The PCV valve system consists of the PCV valve, its mounting grommet, the nipple in the air intake and the connecting hoses. On some engine applications, the PCV valve system is connected with the evaporative emission system.

The PCV valve controls the amount of vapors pulled into the intake manifold from the crankcase. It also acts as a check valve by preventing the flow of air from entering the crankcase in the opposite direction. The PCV valve limits the fresh air intake to suit the engine demand; it also serves to prevent combustion backfiring into the crankcase as well as protecting against crankcase explosions.


PCV Valve

See Figures 1, 2 and 3

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Fig. Fig. 1: PCV location-4.6L shown

  1. On some models it may be necessary to remove the air cleaner outlet tube.

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Fig. Fig. 2: Exploded view of the PCV system-1983 3.8L shown

  1. Disconnect the vacuum hose from the PCV valve.

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Fig. Fig. 3: Exploded view of the PCV system-1984-87 2.3L turbo shown

  1. Remove the PCV valve from its mounting grommet.

To install:
  1. Inspect the mounting grommet and PCV hose, replace if necessary.
  3. Place a small amount of clean engine oil onto the valve end portion to be inserted into the grommet. Then insert.
  5. Place the PCV hose on the exposed valve end.
  7. If removed, install the air cleaner outlet tube.

Crankcase Ventilation Filter

See Figure 4

Replace or inspect cleaner mounted crankcase ventilation filter (on models equipped) at the same time the air cleaner filter element is serviced. To replace the filter, simply remove the air cleaner top cover and pull the filter from its housing. Push a new filter into the housing and install the air cleaner cover. If the filter and plastic holder need replacement, remove the clip mounting the feed tube to the air cleaner housing (hose already removed) and remove the assembly from the air cleaner. Installation is the reverse of removal.

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Fig. Fig. 4: To replace the holder and filter assembly, remove the clip mounting the feed tube