CHECKING AND ADJUSTING TENSION
See Figures 1 through 8
The belts on your Mitsubishi should be inspected and adjusted every 15,000 miles (24,000 km). They should be replaced every 30,000 miles (48,000 km). It is a good idea to first inspect the belts and then turn the engine over by engaging the starter for a split second in order to permit re-inspection of the belts in another position. This way, worn areas will not be hidden by the pulley sheaves. You'll have to replace belts that show severe wear if you want to avoid a breakdown on the road.
Belts must run under constant tension in order to ensure slip-free performance. Belts that slip will overheat and wear out at a very high rate. Too much tension, on the other hand, may cause premature failure of alternator, water pump, or power steering pump bearings.
Estimate tension by pressing a belt halfway between pulleys with thumb pressure (about 20 lbs. or 9 kg). The belt should deflect downward 1 / 4 - 3 / 8 in. (6-10 mm). Note that "deflection" does not refer to play or droop, but stretch. If the belt requires adjustment, use wrenches at both ends of the alternator or power steering pump support bolt and loosen it. Then loosen the adjusting bolt that passes through a slotted bracket. Pull (pry with an appropriate prybar, only if necessary) the alternator or power steering pump away from the engine block to create tension and hold it in position while you tighten the adjusting bolt.
On some later model vehicles, belt tension is adjusted by loosening the tension pulley locknut, turning the adjusting bolt on the tension pulley. Once you've reached the proper belt tension, tighten the locknut to retain the adjustment.
If possible, do not pry on the component. If you cannot get enough tension on the belt without prying, make sure to pry with an appropriate prybar squarely on the front of the housing right where the adjusting bolt passes through it. After tightening the adjusting bolt, tighten the support bolt and nut.
REMOVAL & INSTALLATION
If you're replacing a belt, use the previously described procedure, but move the accessory toward the engine block after you've loosened the support and adjustment bolts. Then work the belt off the pulleys. Make sure to move the accessory far enough so that the new belt can be installed without forcing it on. If moving the accessory until it is at the inner end of the adjusting slot still does not permit easy installation, you've probably got the wrong belt. Prying a new belt on with a prytool will damage it and could substantially shorten its life.
Where there are two belts and you have to replace the one that is located farther back on the crankshaft, you'll have to remove the front belt first.
Once the belt is over the pulleys, pull the accessory outward and tension it (slotted type adjustment or tension pulley) as described earlier. New belts should be adjusted just a little tighter than ones that are used. It's a good idea to recheck tension after running the engine for five minutes and then again after a few hundred miles of driving.