Follow the manufacturer's recommendations for the replacement interval for the belt. This varies from 20,000 to 60,000 miles. Some manufacturers have longer intervals. When no recommendation is made, timing belts should be changed every four years.
If a belt slips or breaks it can cause interference to the engine, resulting in costly damage.
Replacing A Timing Belt On An OHC Engine
Disconnect the negative cable from the battery prior to removing and replacing the timing belt.
Carefully remove the timing cover. Be careful not to distort or damage it while pulling it up. With the cover removed, check the immediate area around the belt for wires and other obstacles. If some are found, move them out of the way.
Align the timing marks on the camshaft's sprocket with the mark on the cylinder head. If the marks are not obvious, use a paint stick or chalk to clearly mark them.
Carefully remove the crankshaft timing sensor and probe holder.
Loosen the adjustment bolt on the belt tensioner pulley. It is normally not necessary to remove the tensioner assembly.
Slide the belt off the crankshaft sprocket. Do not allow the crankshaft pulley to rotate while doing this.
Art courtesty of Delmar - Thomson Learning.
To remove the belt from the engine, the crankshaft pulley must be removed. Then the belt can be slipped off the crankshaft sprocket.