How to tension serpentine belts (or a better tool?)

[michaelluscher]

So I finally switched in the 150 amp alternator into my Camry
I want to set the belt tension correct, as the FSM states

Problem is, no gauge I have or can find will fit down onto the belt
I've got this one

Which works...
On maybe 3/4 of the belts on my classic G body, that's all it's been good for
It's much too large and bulky, and if it doesn't face you it's readings are useless
And I bought 2 of these "Krickt" clicky deflection deals, that IMO have been nothing but confusing and a source of frustration

I want to set it right where it won't squeal, but I don't want to burn up my (knock on wood) A+ 160k old A/C compressor, and nice new alternator
How's everyone else doing this?
You've only barely got enough room to get your hand on it, and forget about the power steering belt

Do they make a tension gauge with a cable on it where it'll reach into tight spaces (think FWD Toyota V6)?

 

[slacktide_bitog]

Oh, I just thought it went by deflection (for example, 7mm when pushed from a certain point)

 

[AutoMechanic]

Never seen anything like that I have always been told just put it back on and make sure it’s lined up.

 

[michaelluscher]

Never seen anything like that I have always been told just put it back on and make sure it’s lined up.

This is manual tensioning
Before automatic spring loaded tensioners

 

[AutoMechanic]

This is manual tensioning
Before automatic spring loaded tensioners

Oh ok never seen that before lol. Thanks for the info.

 

[The Critic]

Never seen anything like that I have always been told just put it back on and make sure it’s lined up.

No offense intended, but based on this post and a few of your other ones, it does not appear that you received quality mentoring at your dealer.

 

[The Critic]

So I finally switched in the 150 amp alternator into my Camry
I want to set the belt tension correct, as the FSM states
View attachment 33464
Problem is, no gauge I have or can find will fit down onto the belt
I've got this one

Which works...
On maybe 3/4 of the belts on my classic G body, that's all it's been good for
It's much too large and bulky, and if it doesn't face you it's readings are useless
And I bought 2 of these "Krickt" clicky deflection deals, that IMO have been nothing but confusing and a source of frustration

I want to set it right where it won't squeal, but I don't want to burn up my (knock on wood) A+ 160k old A/C compressor, and nice new alternator
How's everyone else doing this?
You've only barely got enough room to get your hand on it, and forget about the power steering belt
View attachment 33474
Do they make a tension gauge with a cable on it where it'll reach into tight spaces (think FWD Toyota V6)?

I don't think there is a commercially available one that would fit into that space, easily.

 

[AutoMechanic]

No offense intended, but based on this post and a few of your other ones, it does not appear that you received quality mentoring at your dealer.

None taken. They didn’t train on a whole lot just put me in front of a computer screen for a few days then put me with a tech for a month or so then I was on my own. They didn’t teach us about anything older because it rarely would come in but I wish they would have. I recently left the dealership now looking for a new mechanic job haven’t had any luck yet finding one but I am sure I will my neighbor said he might be able to get me on with the trucking company he works for as a mechanic since I also have diesel experience.

 

[OIL_UDDER]

We did it with natural frequency in production because of this exact problem. To bad that math and tool is not available to the public. Real slick....

Wish I could help on the packaging. Always an issue.

 

[92saturnsl2]

I've always just tightened them till it "feels right" erring on the side of too loose. If the belt squeals, I crank 'er down a little more.

For my Maxima, that winds up being about 1/2" deflection across the furthest pulleys.

 

[Oro_O]

That whole OP nonsense is so dealers don't have to hire knowledgeable mechanics - just send an enabled monkey to do the job.

1/2 way through the belt's free length (between pulleys), push firmly with your thumb. Firmly, not hard. Maximum deflection 3/8"/10mm.

Done - that's it.

 

[atikovi]

How to tension serpentine belts (or a better tool?)

View attachment 33474

You're already using the best tool for the job in the picture, your fingers. If it feels tight and doesn't move over a half inch when you press down, it's fine and you can tighten the adjuster.

 

[doitmyself]

These "do it by feel" recommendations are often difficult for us DIYers that have never had a mentor show us. I do belts by feel, but at my workplace I have a Browning pencil type tension gauge for our greenhouse exhaust fan belts and I always enjoy having an instrument giving me some readings, just like I enjoy using a torque wrench on lug nuts and a refractometer on coolant. Same for spark plugs - nice when I can use a torque wrench and good enough when I am forced to do it by feel.

Bearing adjustment is the same. Do it by feel, but whose feel? 90 lb. weakling or gorilla? Deflect the belt 3/8 inch, but do you push at 10 pounds pressure or 20?? I know, the answer is press it "not too hard", LOL.

I haven't wrecked too many things over my DIY career by "feel", but there have been some school-of-hard-knocks lessons, LOL. I know the pros have these moments occasionally also.

 

[madeej11]

Maybe if you can slip

No offense intended, but based on this post and a few of your other ones, it does not appear that you received quality mentoring at your dealer.

Yeah, I noticed that too Mr. Critic. Maybe the user name is what mislead us. Seems some of the stuff that he doesn't know is elementary.

 

[Timmastertech]

https://gmtoolsandequipment.com/en-US/Pages/ItemDetail.aspx?SKU=BT-3386-FVT This might work for you. Used to be used to measure timing belt tension on some GM engines. I dont remember the tension numbers on it off the top of my head. I have one somewhere but its been years since I have seen it. It doesnt help but we usually tension by feel, couldnt tell you the last time I used a tension gauge

 

[Kruse]

Oh ok never seen that before lol. Thanks for the info.

RE: manual adjusting of serpentine belts. If you ever see some mid to late 90s Jeeps with the 4.0 engine, pop the hood on it and inspect it. I've got two '96 Cherokees with the 4.0 and the adjustment is manual. Sometimes, depending on the belt manufacturer, it's somewhat trial and error to get it perfect.

 

[92saturnsl2]

These "do it by feel" recommendations are often difficult for us DIYers that have never had a mentor show us.

I never had anyone show me, but the first time I did a manual tension, I had already done several belt replacements on vehicles that had automatic tensioners-- so I had at least a rough benchmark of how tight the belt should be. He also removed the old belt, so that should have been somewhat of a reference. If you err on the side of too loose, the worst that can happen is you go back in and tighten it up a notch or two if you notice squealing. Just don't let it keep squealing or you run the risk of glazing the belt.

After setting it initially, turn the A/C on, bunch of electrical accessories, and work the power steering (if on same belt) to put a load on it-- if it doesn't squeal at varying RPMs and you're confident it's not too tight, it's good in my book.

 

[AutoMechanic]

RE: manual adjusting of serpentine belts. If you ever see some mid to late 90s Jeeps with the 4.0 engine, pop the hood on it and inspect it. I've got two '96 Cherokees with the 4.0 and the adjustment is manual. Sometimes, depending on the belt manufacturer, it's somewhat trial and error to get it perfect.

Thanks. I do have a 2001 Jeep Cherokee 4.0 but I think it’s automatic one but not sure.

 

[DGXR]

I thought that serpentine accessory drive systems all had automatic tensioners because all the cars I owned either had V-belts or auto-tension serpentines. No I am not a dealer technician.

 

[atikovi]

Nope.