All engines covered in this guide, except the 1.5L (VIN J) and 1.5L (VIN E), use hydraulic valve lash adjusters. No periodic valve lash adjustments are necessary or possible on these engines. If the engine is determined to have a valve tap, a complete inspection of the valve train must be made to determine the faulty components.
The 1.5L (VIN J) and 1.5L (VIN E) engines use manual valve lifters which require periodic adjustment.
Valve adjustment determines how far the valves enter the cylinder and how long they stay open and closed. If the valve clearance is too loose (large), part of the lift of the camshaft will be used in removing the excessive clearance. Consequently, the valve will not be opening as far as it should. If the valve clearance is too tight (small), the intake valve and the exhaust valves will open too far and they will not fully seat on the cylinder head when they close.
Improper valve adjustment can have several effects on engine performance. If valve adjustment is too loose, the valve train components will emit a tapping sound as they take up the excessive clearance. Engine performance will be poor because the valves are not opening fully and allowing the proper amount of gases to flow into and out of the engine.
If valve adjustment is too tight, the valves may not seat against the cylinder head. The engine will run poorly because of the gases escaping from the combustion chamber and damage to valve train components may result due to overheating.
See Figures 1, 2 and 3
- Run the engine until it reaches normal operating temperature and then turn it OFF.
- Remove the spark plug wires from their clips on the rocker cover.
- Remove the rocker cover bolts and carefully lift the rocker cover off the cylinder head.
- Using a torque wrench, ensure all cylinder head bolts are all tightened to specification.
- Remove the spark plugs to make it easier to turn the engine manually.
- Turn the crankshaft pulley to bring the No. 1 piston to TDC of the compression stroke.
- Adjust the valves marked "A" in the illustration, using a feeler gauge.
Valve clearance should be as follows:
- 1.5L (VIN J) engine-0.006 in. (0.15mm) Intake, 0.010 in. (0.25mm) Exhaust
- 1.5L (VIN E) engine-0.010 in. (0.25mm) Intake, 0.012 in. (0.30mm) Exhaust
- A feeler gauge of the proper size should fit between the rocker arm and the tip of the valve with a slight drag. If the clearance is not correct, loosen the locknut and turn the adjusting screw to obtain the proper clearance. Tighten the lock nut securely.
- Turn the crankshaft pulley to bring the No. 4 piston to TDC of the compression stroke.
- Adjust the valves marked "B" in the illustration, using a feeler gauge.
- Using a new gasket and the proper adhesive, install the rocker cover and tighten bolts to 48-60 inch lbs. (5.4-6.8 Nm)
- Start the engine and check idle speed. Readjust as necessary.