There are four steps on how to measure pulley size. One of the step-by-step instructions is to diameter of driven pulley) times (revolutions of driven pulley) divided by (revolutions of driven pulley) equals (diameter of driver pulley).

Super easy!

Step 1: Get the idler pulley from autozone for $18 bucks

Step 2: Loosen the serpentine belt by turning down the tensioner (to your bottom left); you should be able to do this with your hands...no tool required.

Step 3: Take off the S. belt

Step 4: Use a 18 mm wrench to turn the idler pulley's center bolt.

Step 5: Replace the Idler pulley

Step 6: Replace the S. belt

Step 7: Push the tensioner back into th eup position to tighten then S. belt.

This should take you 13 minutes going slow...

Requires two person team. Step One: Look at serpentine belt diagram on front of engine. Arrow points to idler tension pulley. (Front Left side of engine) Loosen this 15mm bolt. Step Two: Loosen Idler pulley bolt - 15mm. Step Three: One person push down on idler tension pulley with tire removal tool or cheater bar on front left of engine while second person lifts belt off alternator. Step Four: Remove Idler pulley and replace with new one. Tighten bolt to idler pulley Step Five: One person push down on idler tension pulley with while the other fits belt on alternator and around idler pulley. Step Six: Make sure belt fits as noted on belt diagram and Tighten bolt on idler tension pulley (front left side of engine). Approximate time: 10 minutes

depress the tensioner pulley with a ratchet and take off the belt installation is the opposite

(step one) line up your crank pulley on zero with the mark on the pulley.

(step two) the one dot on your diesel pump should be centre of the crank gears two dots.

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(step three) line up the two dots on the cam gear with the arrow on the first cam cap behind the gear