Hyundai Coupes/Sedans 1986-1993 Repair Guide

General Information


See Figures 1 and 2

All vehicles are equipped with a closed crankcase ventilation system. The system is composed of a Positive Crankcase Ventilation (PCV) valve and related hoses. This system prevents blowby gases, burned gases which pass the piston rings during combustion, from escaping into the atmosphere. The exhaust gases include Hydrocarbon (HC), Carbon Monoxide (CO) and Oxides of Nitrogen (NOx).

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Fig. Fig. 1: Positive crankcase ventilation (PCV) system on carbureted vehicles

The system supplies fresh air to the crankcase through the air cleaner. Inside the crankcase, the fresh air is mixed with blowby gases, which pass through the PCV valve into the induction system.

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Fig. Fig. 2: Positive crankcase ventilation (PCV) system on fuel injected vehicles

The PCV valve has a metered orifice through which the mixture of fresh air and blowby gases are drawn into the intake manifold in response to the manifold vacuum. Under low vacuum conditions (heavy acceleration) the mixture is backed up into the air cleaner.


PCV Valve

The PCV valve should be checked every 15,000 miles and cleaned or replaced as required. Refer to General Information & Maintenance for PVC valve removal procedures.

  1. Disconnect the ventilation hose from the PCV valve and remove the valve.
  3. Insert a thin stick into the PCV valve from the threaded end and push to check if the plunger moves.
  5. If the plunger does not move, the valve is clogged and should be cleaned or replaced.