Hey guys,
Let me start off by saying I'm normally a pretty good driveway mechanic, and have been working on my own cars for the last 15 years or so. Now, with the backstory out of the way, here's the issue:

Last week I did an oil change and installed new belts on my '06 G35x. I followed the video that I found on infinitihelp and it made the job easy - besides, it was the same procedure I had to do on my '01 Jeep Cherokee, so I was familiar with the concept of the adjustable tensioner.

Anyway, today I was driving home from work, and noticed a whistling sound coming from the engine bay. So I popped the hood after I got in the driveway and noticed the AC belt wasn't spinning, because the idler pulley on the AC side FELL OFF and dropped into the tray under the engine. I grabbed it with a magnetic wand, but I haven't pulled the pan to see if the nut and washer are in there as well. I have a feeling they're long gone, so I stopped by the local Nissan dealer and picked up a new tensioner assembly just in case.

So, here's my questions - 1. Is the locknut on the front of the pulley supposed to be super-tight, or will that restrict it's ability to spin? 2. And, where can you find the "belt tensioner gauge" that they use in the vid on infinitihelp? I went to my local parts guy, Sears Hardware, and Autozone, and no one stocks that tool.

Any and all help you guys can give will be much appreciated! Thanks in advance!

 

I reefed on my pulley bolt and made sure it was SUPER tight. Spins fine and mine's still on

 

bolt on the pulley must be tight. It is the only thing that keep the pulley in position and the tensioner from adjusting itself.

 

Awesome guys, thanks for the help! I'm gonna go out now and report my findings later - with any luck, the washer and nut will still be on the shield under the motor and I can return the spare parts to the dealer.

 

FSM shows the nut needs to be torqued to 26 ft/lbs. Doesn't seem like a lot.

ALTERNATOR AND POWER STEERING OIL PUMP BELT
1. Remove undercover with power tool.
2. Loosen idler pulley lock nut (A) and adjust tension by turning
adjusting bolt (B).

For specified belt tension, refer to EM-14, "Checking Drive
Belts" .
3. Tighten nut (A).

34.8 N·m (3.5 kg-m, 26 ft-lb)
A/C COMPRESSOR BELT
1. Remove undercover with power tool.
2. Loosen idler pulley lock nut (C) and adjust tension by turning
adjusting bolt (D).

For specified belt tension, refer to EM-14, "Checking Drive
Belts" .
3. Tighten nut (C).
Removal and Installation ABS00479
REMOVAL
1. Remove undercover with power tool.
2. Remove alternator and power steering oil pump belt. Refer to EM-15, "ALTERNATOR AND POWER
STEERING OIL PUMP BELT" .
3. Remove A/C compressor belt. Refer to EM-15, "A/C COMPRESSOR BELT" .
: 34.8 N·m (3.5 kg-m, 26 ft-lb)

 

Thanks again guys! Believe it or not, the washer and nut were still on the tray under the motor. I thought they would have slid out the big hole by the drain plug. So I put everything back together with the original parts, cranked down on the nut this time, and took it out for a drive. All is well, so I'll return the other parts Monday. Thanks again for the help!!!