I replaced the alternator in my 01 4WD Pathfinder yesterday, I'd read about it being a tough job but it wasn't too bad. Here are some notes for anyone considering it -



The telltale sign of a bad alternator are the dash lights below. In this state it is not charging so you will not be able to drive very far. In my case as the car warmed up the lights cleared and the truck worked fine. Until it didn't.


I bought the HITACHI ALR0012 from RockAuto.

10, 12, and 14mm wrenches and sockets are needed. Having a ratchet-end 10mm wrench could save a lot of time with the fasteners on the back of the alternator. I did the job without one though.

First I removed the battery, fan shroud, and fan, loosened the belt tension pulley and removed the belt. The fan shroud comes off in 2 pieces. Remove the lower section from under the truck by releasing the set of plastic clips on each side, then navigate it out from underneath. Having good lighting helps to locate the clips. The top of the shroud is held on by a couple 10mm bolts and is removed from the top. It may not be necessary to remove the fan, but it comes off easily by unfastening 4 10mm bolts.

I removed the radiator - not necessary but I did not want to damage it and wanted the extra working room. It is easy to remove, drain it from the plug underneath into a container and set aside. Remove and plug the transmission fluid hoses, remove the top and bottom coolant hoses, unbolt and remove.

The alternator is fastened to a bracket on the lower side and a long 14mm bolt at the top. This 14mm bolt is not tapped into the block, instead it is held by a nut welded to a small angle iron. Access to this nut is very limited, you might need to pry some of the wiring away to even see it. You can use a telescopic magnet tool to keep the nut from dropping and becoming lost when you remove the long bolt.

After unfastening the alternator, tilt it to get better access to the connections on back. Remove the power connection under the rubber boot and ground wire on the 10mm bolt. Then remove the 10mm bolt used to fasten the wiring harness to the alternator. Access to this bolt is very limited, this is where a ratcheting end 10mm wrench would help. Once the bolt is off, remove the alternator from the front.

Reverse the steps to install the new alternator. The only tricky parts are getting the 10mm bolt on the wiring harness threaded to the back of the alternator, and getting the 14mm angle-iron nut in place to thread the long bolt.

Thanks for the tips.

Wow thank you much appreciated. I haven’t had to do mine yet but starter and alternator will be in my future at some point.

Just adding to the great information, there are two 10mm bolt holding wiring harness and the ground wire at the back of the alternator. taking out is easy, but when put it back in, I had to temporarily mount the alternator main bolt and installed the 10mm bolt holding the wiring harness. The airing harness plate was actually about one mm or two mm closer to the engine, and I didn't realize it until after spending almost two hours fumbling around with the bolt.

Once mount the 10mm, I took the alternator main bolt out and installed the ground 10mm and battery positive cable to the alternator. Then reinstalled the alternator main bolt and reconnect the wiring harness.

Like mentioned above, I used magnetic pickup tool to hold the rear nut retainer bracket while attacking the rachet and socket to the front of the bolt. from under the car with a spot flashlight, I can see the rear side of the bolt and use the magnetic holder and nut retainer to the back of the bolt. Using my left hand to hold the nut retainer while rachet it down the bolt from underside, it was done.

Some parts were not easy, but keep cool and take time, I was able to get it done.

Now, after messing around with the bolts and nuts, I almost forgot all the other stuffs and I had to look up the diagram to attach brackets and power steering pump and so on.

When I inspected alternator, the ring sleeve was worn out and was about 1.5mm below the surface. Almost at the end of the life and it was good time to change it. I am going to replace the ring sleeve and brush and clean it to keep it as a spare.

All these were due to the oil leak around the engine oil cooler, and I decide to replace the gaskets and oil pressure sensor at the same time. After 22 years, it is a small maintenance that I need to do.

My pathfinder (2001 4WD) has a crankshaft rear seal leaking slow, but I can live with that.

However, around the engine oil cooler leak is much easier get to, and I decide check, and this became a job!