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When did belt tensioners become commonplace?

In the 1960s and 70s cars, the belts would be tightened manually with a prybar against the loosened alternator.
It seems like mechanical/hydaulic tensioners have become standard across all newer modern cars.

I have started wrenching again after 20 years, and just noticed this.
Around which year did this become a standard?
I am guessing sometime in the 80s or 90s?

I just typed in 1980 T-bird and it has a mechanical tensioner on the 302.
I thing about anything with a multi-grooved / serpentine belt will have the tensioner.

My memory is very hazy but I seem to remember replacing a few tensioners on the mid 80s Mustangs. The first Taurus and Sable cars (1986) had serpentine belts but used a manually adjustable tensioner instead of a spring loaded one.
I think the mid 80s was the point at which things changed with all or most car makers.

I guess it must have been the '80s that air conditioning and power steering became the norm for all cars. Once you get that many pulleys, you need idlers to ensure sufficient wrap on all of them, and then you need tensioners to ensure sufficient tension is maintained.

I’m gonna say the '80s. My '89 Toyota pickup did not have power steering or AC, and I believe that still had a V-belt. If I’d have gotten AC and/or power steering, it might have had a ribbed belt.

While the serpentine belts were the major starting point for automatic belt tensioners, I think most a/c systems had a manual tensioner for the v-belt.

One reason for the push to serpentine belts with an automatic tensioner is that the accessories could now be firmly mounted to the engine, which reduced NVH (noise, vibration, and harshness). Hard to do with an alternator on a spindly adjustable bracket.

The first serpentine belt and auto tensioner I saw was on my 1983 Mustang GT.

Ed B.

When the serpentine belts came in. About 85 or 86 on GM depending on the model.

I agree with the peceding remarks. Our 1976 Ford Granada V8 was loaded, and had a fan/alternator belt, power steering belt, smog pump belt, and air conditioner belt. All had manual adjustment. When the smog pump belt went, we did not replace it since in my area there were no emission inspections.

All those belts occupied a lot of space and made a lot of noise. But at the time you could still buy a Granada with no power steering, no Air, and you would then only have 2 belts.

My 1971 Maverick with a 250 cubic inch 6 cylinder engine, air conditioning, and power steering used a matched set of belts and dual pulleys on the crankshaft, water pump, alternator, air conditioner compressor and power steering pump. I think that the present serpentine belt with a tensioner is really a better system.

This changeover started in the late 70’s and by the mid-'80’s most motors had serpentine belts with a belt tensioner. In the 60’s and early 70’s you had a pully on the crankshaft that would accomdate 2 or 3 belts. There was an alternator belt, a power steering belt, an AC belt. As things got more congested in the motor compartment the serpentine belt driving all the accessories came into common use. The serpentine belt needed a “tensioner” to accomadate the slack in the belt as it stretched and wore over the years and miles.