My 99 Q just had upper idler pulley burn up and replaced with new pulley and belt and after starting head a slight chirping sounded like squeeking belt but when I took it for a test drive, it began to sound like another pulley going bad, and when I accelerated there was a roaring vibration from the front like I was in first gear, but then I decelerated and it went away momentarily but happened again after leaving a stop light. When I got home and checked under the hood, there was noise and vibration coming from the fan. When I turned off the engine and checked for loose belts and pulleys, I noticed that the fan blade would not spin like it used to and two of the four bolts which connect the fan to the water pump were completely gone, just the empty holes. First I thought there might be something out of balance, but then I thought about the clutch and decided to see if anyone here has had any problems like this. Any help on this greatly appreciated.

Yes there are times where we will see fan clutches lock up.. On the older Q there are studs that thread into the water pump that hold the fan onto the water pump pulley, sounds like maybe a couple got broken? I would definitely get that fixed, if the fan flew off the pulley that would be really bad... You would most certainly wreck your radiator and maybe even the hood?

I would personally check your other pullies too, because chances are the other 2 arent far behind...

I assume that when a fan clutch locks up it means it should be replaced, but how can the studs be broken off, and how can they be replaced. I was careful not to over tighten them, this looks like a new water pump too, or do the studs even come with a new pump? Can they be drilled out? I have already ordered the other two pulleys I haven't replaced yet, so that should take care of the rest. I replaced the crank pulley last summer. Thanks for the help and anything you can add will be very helpful.

dead thread but need help asap. I was replacing the belts on my 99 and one of the fan clutch studs sheared in half, do i need to order a new water pump or can i just get the studs at an infinity dealer, ive been looking all over and all i can find are whole pump kits or general motors fan clutch studs and i dont wanna chance something being the wrong thread/length without asking here first.

lol just noticed i hit this thread 11 years to the day what are the odds

InfinitiPartsDeal.com shows the studs are separate parts and are still available, p/n 08226-62010, $2.67 list. It also shows up as a good Nissan p/n, so you're not limited to the Infiniti dealer to get one.

I used a 90 degree drill chuck adapter with my Dremel to drill a hole into the center of the stud, and then with an easy-out managed to get the remaining piece of the stud out, and then purchased new studs. I agree that you must be careful not to over tighten the studs and the nut when installing them. Since there was so much havoc under the hood that day, I decided to replace all pulleys, idlers, and belts. I also replaced the fan clutch, and the fan as well. I'm not sure the fan clutch was the problem, but any pulley or idler would have created a similar disaster.

dlduscg wrote: ↑

Wed Dec 15, 2021 5:41 pm

I used a 90 degree drill chuck adapter with my Dremel to drill a hole into the center of the stud, and then with an easy-out managed to get the remaining piece of the stud out, and then purchased new studs. I agree that you must be careful not to over tighten the studs and the nut when installing them. Since there was so much havoc under the hood that day, I decided to replace all pulleys, idlers, and belts. I also replaced the fan clutch, and the fan as well. I'm not sure the fan clutch was the problem, but any pulley or idler would have created a similar disaster.

thank you so much Vstar for the lead, ill look into it tommorow its late now. thankfuly the stud isnt completley stuck in there prolly gonna be able to get it out with pliers, and yes most definetly gonna be careful tightening it next time as im pretty sure it sheared when we were putting everything back together first time doing the belts, as the water pump wasnt on level and we thought tightening down the fan clutch would even it out. pretty sure we just tightened s*** in the wrong order.

found the parts site gonna keep looking but anyone know where i could find the 14mm idler pulley nuts as those are stripped too. ordered the studs, 4 new ones they should come in next week. can i use normal 10mm nuts or do i need to get some at a certian spec, half of the fan stud nuts are stripped.

shaggythakidd wrote: ↑

Thu Dec 16, 2021 2:48 am

found the parts site gonna keep looking but anyone know where i could find the 14mm idler pulley nuts as those are stripped too. ordered the studs, 4 new ones they should come in next week. can i use normal 10mm nuts or do i need to get some at a certian spec, half of the fan stud nuts are stripped.

The nuts are available from Nissan or Infiniti too, p/n 01225-00751. You just want 4 identical so you don't induce any imbalance, but if you need to use plain ones from the hardware store, use a split lockwasher on each. That's one spot where you don't want any chance of them backing out.

Also use blue Loctite , won't loosen , and so you wont be all anal and OCD about getting it TIGHT, too TIGHT yeah it breaks . Even a 1/4 drive small tork-wrench to limit yourself , yknow.

No need for Loctite or over-torqueing with split locks, that's why I prefer them. Using the OE nuts, yes, Loctite preferred.

VStar650CL wrote: ↑

Thu Dec 16, 2021 4:55 am

You just want 4 identical so you don't induce any imbalance...

One of the nuts had a washer stuck to it and another was slightly different from the top two. dont know how long it ran like this, what kind of damage could it cause?
Been figuring out the infinityparts site and found the 14mm idler pulley nuts i needed, ordered those and 4 10mm from the fan clutch. now hopefully once everything gets here and i get it installed it will be dailyable. prolly gonna update or start a thread for the Q cause i kinda wanna document the work for anyone else with a y33.

VStar650CL wrote: ↑

Thu Dec 16, 2021 8:38 am

No need for Loctite or over-torqueing with split locks, that's why I prefer them. Using the OE nuts, yes, Loctite preferred.

also will permatex medium strength blue threadlocker work instead or am i gonna have to go out and grab some of this loctite stuff

Permatex is fine, you just don't want to use the high-strength stuff in case it ever needs to come loose again.

dlduscg wrote: ↑

Wed Dec 15, 2021 5:41 pm

I used a 90 degree drill chuck adapter with my Dremel to drill a hole into the center of the stud, and then with an easy-out managed to get the remaining piece of the stud out, and then purchased new studs. I agree that you must be careful not to over tighten the studs and the nut when installing them. Since there was so much havoc under the hood that day, I decided to replace all pulleys, idlers, and belts. I also replaced the fan clutch, and the fan as well. I'm not sure the fan clutch was the problem, but any pulley or idler would have created a similar disaster.

When you got the new studs did you have any issue trying to put them in as opposed to the old ones? I have all 4 new studs and only one will go in easily, I ordered the ones that match my motor (VH41) and they look near identical other than being slightly longer. Might use two new ones and the two surviving old ones.

so....this is a longshot, but did you try turning the new studs 180deg and then try threading them?
sometimes (can't recall on the VH41), the water pump threads are a different pitch than the nuts that hold the fan clutch to the pulley.
If all that checks, might need to gently chase the threads in the water pump.

yes............yes,,,,,,,,,yes NOT such a longshot

3Q Jay wrote: ↑

Thu Dec 23, 2021 2:07 pm

so....this is a longshot, but did you try turning the new studs 180deg and then try threading them?
sometimes (can't recall on the VH41), the water pump threads are a different pitch than the nuts that hold the fan clutch to the pulley.
If all that checks, might need to gently chase the threads in the water pump.

ended up putting the nuts onto the smooth part of the stud, putting loctite on the part that went into the water pump and slowly tightened it down and that got them all threaded. ended up being futile tho, as when putting it all back together we broke the power steering tensioner pulley and i decided to just take it to the shop at that point and found i needed a rack and pinion, p/s pump, tensioner pulley, water pump, and a new battery. got it all for 1680 parts and labor with an alignment included.