Valve adjustment determines how far the valves enter the cylinder and how long they stay open and closed.
If the valve clearance is too 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. This condition has two effects: the valve train components will emit a tapping sound as they take up the excessive clearance and the engine will perform poorly because the valves don't open fully and allow the proper amount of gases to flow into and out of the engine. If the valve clearance is too 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. When a valve seats itself on the cylinder head, it does two things: it seals the combustion chamber so that none of the gases in the cylinder escape and it cools itself by transferring some of the heat it absorbs from the combustion in the cylinder to the cylinder head and to the engine's cooling system. If the valve clearance is too small, the engine will run poorly because of the gases escaping from the combustion chamber. The valves will also be come overheated and will warp, since they cannot transfer heat unless they are touching the valve seat in the cylinder head.
The Sonata and Elantra engines are equipped with hydraulic valve lash adjusters, which require no adjustment or regular maintenance.1468cc and 1495cc Engines
See Figures 1, 2, 3 and 4
Valve clearance is adjusted with the engine off.
- Run the engine until it reaches normal operating temperature and then turn it off.
- Remove the air cleaner. Pull the large crankcase ventilation hose off the front of the air cleaner. Disconnect the 2 smaller hoses, one goes to the rear of the rocker arm cover and the other to the intake manifold.
- Loosen and remove the nuts and bracket which attach the air cleaner to the rocker arm cover.
- On carburetor equipped vehicles, lift the bottom housing of the air cleaner off of the carburetor and the hose coming up from the exhaust manifold heat stove.
- Remove the spark plug wires from their clips on the rocker arm cover.
- Using a deep socket or box wrench, remove the rocker arm cover bolts.
- Carefully lift the rocker arm cover off the cylinder head. Using a 5/16 in. (8mm) Allen socket and a torque wrench, make sure the cylinder head bolts are all tightened to specification.
- Hot valve clearance is 0.006 in. (0.25mm) for the intake valves and 0.010 in. (0.30mm) for the exhaust.
- Turn the crankshaft pulley to bring the piston to TDC of the compression stroke on the cylinder being adjusted.
- Loosen the rocker arm adjusting screw locknuts.
- Using the correct thickness feeler gauge, turn the adjusting screw until the gauge just snaps through the valve stem and the rocker arm.
- Repeat the procedure to adjust the valves of each cylinder.
Loose valve clearances will result in excessive wear and valve train chatter. Tight valve clearance will result in burnt valves. Make sure to set the valve clearance to the exact specifications.
- Apply non-hardening sealer to the rocker arm cover gasket. Always use a new gasket.
- Install the cover, hoses, spark plug wires and the air cleaner in the reverse order of removal. Tighten the rocker arm cover bolts to 48-60 inch lbs. (5.4-6.7 Nm)
- Start the engine and check for leaks.