Article submitted by Sandbag
How to replace a Crankshaft Pulley Assembly on a 4 cyl Nissan Frontier:
Pics are at the bottom of the write-up.
Haynes Shop Manual
Misc drivers and breaker bars
Pry bars or pulley removal tool
Chain wrench (or equivalent)
Remove Negative cable on battery.
Remove all accessory belts.
There's an idler pulley on the driver's side of the engine that uses a 14mm adjuster bolt.
There's another idler pulley for the AC Compressor that also uses a 14mm adjuster bolt. This is located on the driver's bottom side of the engine.
Finally, using a 12mm socket, loosen the adjuster bolt assembly for the Alternator. There is also a 14mm bolt on the bottom of the alternator that needs to be loosened.
Remove the fan blade assembly by removing the 4 10mm nuts located on the water pump. You will also remove the water pump pulley at this time. It just slides off the studs that hold the fan assembly.
Remove Radiator Shroud.
Using the chain wrench, snug up on the pulley to hold it in place. Use the 28mm socket to loosen the retaining bolt for the pulley assembly. This is a standard threaded bolt – not reverse thread.
After the bolt has been removed, you can either use a pulley remover tool, or a pair of pry bars. I used the pry bars because the removal tool I rented had a small diameter threaded rod, and it would have messed up the threads on the crank. If you use the pry bars, CAREFULLY apply equal pressure to avoid damage to the crank shaft.
Install new Crankshaft Pulley Assembly. For this, I used some bearing grease, and applied a bit into the sleeve on the pulley. Make sure to line up the key on the crank to the keyhole on the pulley. At this point, I used a small block of wood, and a small hammer to get the pulley seated. I then used the bolt for the pulley to seat it on the crank. If you do this, be careful, and pay attention to how the driver feels while tightening the bolt. There is a good potential for stripping the threads on the crank. So again, please watch for any signs of stripping threads. A drill and tap on the crank would not be fun.
Torque the pulley belt to the specs called out in the Haynes Manual. I believe it is 105-112 ft/lbs or there abouts.
Reinstall Fan Shroud.
Reinstall Water Pump Pulley and Fan Assembly.
Reinstall the accessory belts, starting with the AC, then Alternator, and finally the Power Steering belt.
Attach negative battery cable.
Congratulations! You've just successfully installed a Crankshaft Pulley Assembly!
New Pulley Assembly:
The only pic I have of it installed: