Looking for advice on how to replace idler pulley in my 98 Pathfinder

[bagofbricks]

Hi all,

I've just bought a 98 Pathfinder and I've been told the idler pulley, the one that I think is next to the alternator, needs to be changed..

I'm a compete noob when it comes to mechanics, but I'm keen to learn and start doing some work myself. I've been told by a friend that an Idler change is a pretty easy job, so I'm gonna give it a shot. Basically there's a bit of a whine when I start my engine, and there is movement on the idler pulley when you wiggle it. I've attached a photo of it.

I've watched a few videos on you tube, but these have all been on different types of vehicles. Could anybody link me to any instructions/diagrams specific to a 98 Pathfinder please? Also, should I be changing the whole pulley, or just the pulley bearing?

Many thanks in advance,

[mdmellott]

This is fairly straight forward. If the idler pulley bearing is shot, you will have to replace the entire pulley/bearing assembly. For your '98 it's Nissan part number 11947-31U05 which can be purchased as an OEM part from https://www.nissanpartsdeal.com/parts/n ... 31u05.html? or other places you may find. There is a field service manual on this website for your '98. In the maintenance section it describes what the proper adjustment is for the belt on this pulley but not much in the way of how to do it. https://www.nicoclub.com/service-manual ... 998/ma.pdf There is also a Haynes Repair Manual https://www.amazon.com/Nissan-Frontier- ... 1563926105 you will find useful. I use both but often find the Haynes manual of more use with real images of the parts being worked on. The pulley assembly is removed by removing the nut in the center of the pulley. The 10mm hex head of the bolt you see in the picture you posted is the tension adjustment bolt for this pulley. Loosen the locknut on the adjustment bolt, loosen the adjustment bolt, and then remove the pulley nut. When you put it back together, install the new pulley/bearing assembly but do not tighten the pulley nut. Just install the nut by hand until it is seated. The belt tension can then be adjusted with that adjustment bolt. When the tension is correct, tighten the locknut on the tension bolt and then tighten the pulley nut. Good luck and welcome to NICOclub.

[bagofbricks]

Awesome, That's just the kind of information I've been looking for, I feel a lot more confident now.

I'll be buying a Haynes manual asap, and I appreciate the link to the service manual.

Thank you!

[AZhitman]

MD, that was a STELLAR post.

Way to take care of the new guy! Welcome aboard, BoB!

[mdmellott]

I just realized, there might not be a lock nut on this belt tension adjustment bolt. If that be the case, just loosen the bolt. You might have to loosen the pulley nut first. I can't tell for sure how the adjustment bolt is captured in the idler pulley bracket. Once you have buttoned everything up with the new pulley, crank over the engine just for a second or two, turn off the engine and check the belt tension again. Readjust the tension if necessary.