Over time, alternator belts stretch. This can result in your alternator not powering your car's electrical features or recharging your battery so when you try to start your car you may find the battery is dead. Additionally, a loose alternator belt can produce an annoying squeal. The actual task of tightening the alternator belt on a Nissan 350Z is not difficult. However, getting your hands and wrench into the small area where the adjuster is located can be a little frustrating, so patience is required.
Disconnect the positive battery cable from your battery using a wrench before attempting to tighten the alternator belt on your 350Z. The positive cable is coloured red.
Remove the plastic engine cover using a screwdriver. There are several screws that need a half-turn counter-clockwise, then the cover un-clips and can be moved away.
Locate the alternator. You can see it between the engine and radiator. On the front of the alternator is a locknut and a bolt fitted through an adjustable bracket. The locknut has to be loosened so you can tighten the alternator belt.
Use two wrenches. Place one at the rear of the bolt to hold it in place. Put the other wrench on the locknut and turn counter-clockwise. Don't undo the nut too much: you only have to loosen it. Remove the wrench from the back of the bolt.
Keep one hand on the wrench and with the other hand pull the alternator away from the engine. The alternator belt will tighten. You need to pull quite hard to get the tension correct. As soon as you have pulled the alternator belt, turn your wrench clockwise until it tightens enough to hold the alternator in place. Use both wrenches to completely tighten the nut and bolt so the alternator cannot move.
Replace the plastic engine cover and turn the screws clockwise to lock the cover in place. A half-turn should be fine. Reconnect the positive battery cable on your 350Z to the positive battery terminal.