Idler pulley bolt

Is the idler pulley bolt on a '99 4.0 a 'lefty-loosey/righty-tighty' operation? I am trying to adjust the tension on my serpentine belt (I got the gauge to do so) and went to loosen the center bolt on the idler pulley... it is VERY stiff and as I was wrestling it over I suddenly wondered if perhaps since it is on a spinning pulley it might be a reverse thread deal.

Probably a dumb question but I'd still like to ask rather than snap the bolt head off!

No room for a torque wrench in there... once I cinch up my belt do I just heave the idler pulley bolt "tight" again?

Thanks -

your talkin about the pully next to the t-stat housing? mine is regualr thread or lefty-loosey, righty tighty

The idler pulley bolt is down a littleon the driver's side...

duke000088 said:

Is the idler pulley bolt on a '99 4.0 a 'lefty-loosey/righty-tighty' operation? I am trying to adjust the tension on my serpentine belt (I got the gauge to do so) and went to loosen the center bolt on the idler pulley... it is VERY stiff and as I was wrestling it over I suddenly wondered if perhaps since it is on a spinning pulley it might be a reverse thread deal.

Click to expand...

The idler pulley bolt is standard right-hand thread.

duke000088 said:

No room for a torque wrench in there... once I cinch up my belt do I just heave the idler pulley bolt "tight" again?

Thanks -

Click to expand...

Right.

-Ed Rico

Right on - thanks - standard right hand thread.

That being said... When trying to loosen the idler pulley bolt (15mm wrench squeezed down in between the pulley and the fan) my bolt was VERY stiff. It feels awful. When I can get it to budge a little it CREAKS real ugly. I'm not a Hulk so I tried tapping on my wrench with a rubber mallet to budge the bolt counter-clockwise and it just doesn't seem to want to loosen up. It does not appear to be rusted up although I'll try some PB for good measure.

Stranger still I found I can turn the adjuster bolt on top with only moderate effort. This makes me think that my idler pulley bolt is either already loose or f'd up and not properly acting as a set screw for the tensioner/adjust bolt. That idler pulley bolt sure does NOT feel loose but who knows if the threads are screwed up or something.

I'm afraid if I keep at the idler pulley bolt I will snap it! :fuse: Not sure how likey this is (hell, it's an XJ, OF COURSE it's likely).

I feel like I understand the procedure 100% but my parts just aren't behaving as predicted.

The pic below I just stole from another post.

The adjuster bolt can be loosened without loosening the idler pulley center bolt, but it will not move the pulley. It will just start to back out. You have to loosen the bolt in the center of the pulley so that the adjuster can move it.

Yes, I understand that. The problem seems to be that the center bolt is seized or close to seizing. Or it is already fairly loose and has messed up threads perhaps.