Why is the serpentine belt tensioner pulley bolt reverse thread?

I’m am always the one to question things.
Is the reason that the the pulley is reverse thread because,
You have to use the pulley bolt to release tension on the belt.
Which requires you to turn the bolt Counter-Clockwise.
And doing this to a Standard Thread bolt cause it to potentially loosen the bolt?

My Older Pre-Runner had 2.7 had a separate spot on the tensioner you used.
Not the actual pulley.

 

It is L/H threaded so the rotation of the belt and pulley will not cause the bolt to loosen and come out.

 

This ^

 

New 2.7 does have serp belts. The motor is still used up to 2020 just “advanced”

 

Old cars used to have reverse thread lug nuts on one side of the car to prevent loosening as well.

 

As said, some old cars and trucks had reverse thread lugs on the LH side. IIRC, Chrysler did this in the 60s-70s. The logic is that the tire rotation when going forward "tightens" the nuts. Unnecessary, but...

 

uhh Same logic as the belt pulley.

 

Cars have had some type of reverse thread bolts/nuts for many decades British wire wheel cars have left and right hand wheel nuts as do some race cars. I can tell you this I have seen wheels come off British cars if they are towed backwards for any real distance it's all about rotation.

 

How do you torque the pulley bolt (reverse thread) to spec when turning it counterclockwise moves the tensioner?

 

Had a 70 Chrysler Belvedere with reverse threads on one side. Think it was the driver's side. There was a notch in the lug nuts so you didn't mix them up.

 

You got it, the ones that pivot in the other direction have right hand thread.

Yep I have an 84 F-250, the left side lugnuts are left hand (reverse) thread and the right side are right hand (standard) thread.

 

Yeah, that was ChryCo vehicles. I had to rotate my own tires because the idiots would spin them off at the tire shop. A lot of us would switch the bolts on the passenger side on our Mopars to just be done with shops reverse threading them and ruining the lugs and having wheels fall off.

 

Chrysler Vehicles were like this.

 

I have never seen this "feature" on a Ford...

 

Could have been a fleet vehicle. Randomly…. Fleets would have all sorts of random options or things they would add at delivery. Especially government vehicles, so they could keep service consistent. My dad used to do all of the negotiating and purchasing on vehicles for the federal government on the west coast. Some of the stories he had about negotiations and requirements were absolutely hilarious.

 

That would annoy the shit out of me lol

 

Just turn it until it stops and torque the bolt. You're not going to hurt it

 

I’ve run across the occasional reverse thread fastener. Usually accidentally. Accidentally snapped it off. Accidentally discovered, it’s stuck, shoot some penetrant, try going back and forth loosen tighten, oh it’s turning. You’d think they’d somehow identify it with some piss yellow paint, or a R stamped into it, something. When you snap it off, extracting it is a pain. Drill with a regular instead of reverse bit hoping it grabs and backs out. Only choice is a straight flute extractor.

 

It's not a fleet truck, my Grandpa bought it new in 84 I have it now it currently has 313k miles on it.
It's not quite as shiny anymore but this is what it looked like in 2010 when I got it.

 

FWIW, I asked the question over 2 years ago.
I forgot I even asked it.