Changing the timing belt on a Highlander should be done every 60,000 miles. This estimate is arrived at through the previous service records for this engine. The 3.0 engine has been determined to be a freewheeling engine in which there is a remote possibility of engine damage if the belt were to fail while operating. Failure of the belt usually means that it stretches beyond the tensioner's limits to keep proper tension on the belt (to maintain timing), but there is also a chance the belt could break. This article will explain how to change a Highlander timing belt.
Remove the accessory drive belts. Remove the cooling fan and the pulley. Remove the alternator and bracket. Remove the crankshaft pulley bolt and the pulley with the puller. Remove the upper and lower timing belt cover. Temporarily install the crankshaft pulley (loosely).
Turn the crankshaft clockwise until the timing marks on the camshaft pulleys are straight up and the mark on the crankshaft sprocket is lined up with the mark on the block which is straight up at 12 o'clock. Remove the tensioner from under the engine. The bolts are going straight up. Remove the timing belt.
Compress the auto tensioner in a vise carefully until the top hole in the rod is aligned with the holes in the tensioner body. Insert a cotter pin through the tensioner body and the rod to keep it compressed.
Install the new timing belt counter clockwise starting on the right side, away from the tensioner at the crankshaft sprocket to the inside of the water pump, around the right camshaft sprocket, then under the idler pulley and over the left side cam. Install the tensioner pulley and torque the bolts to 20 foot pounds of torque. Pull the cotter pin out of the tensioner and allow it to operate.
Rotate the engine two times clockwise and recheck the timing marks. If the marks are lined up, install all components in the reverse order of removal and torque the crankshaft pulley bolt to 155 foot pounds. If the marks are not lined up, remove the timing belt and repeat Step 4 and Step 5.
