How long does a drive belt tensioner last?

[mat82284]

I've never really looked at my tensioner as getting old. Its got 113k miles on it. I'm assuming you would want to replace them after 100k?

I noticed that my tensioner shakes when the car is at idle and moves back and forth releasing tension a little. I'm not sure if this is causes by the cams, maybe its shaking the engine and its just an effect from that? The car drives fine, I rarely use boost so i wouldnt have noticed any drop in boost, but I was wondering if its time to replace it, how would one know? Are the Gates ones any good?

 

[wmburns]

As for constant excessive shaking/adjusting, look at the run out on the crank shaft damper (or the other pulleys). Over time, the rubber between the outer and inner ring will shrink. This allows the outer ring to "run out" as compared to the crank shaft.

More likely that is the source of the constant adjusting.

There is one school of thought that say the tensioner will last the life of the car. However, that is most likely unrealistic. I suspect there is a way to measure the spring tension and determine if the spring is weak. However, the cost of the tool may exceed the cost of a new tensioner.

In my experience, the bearings give out before the spring thus rendering the question moot.

 

[mat82284]

As for the shaking/adjusting, look at the run out on the crank shaft damper (or the other pulleys). Over time, the rubber between the outer and inner ring will shrink. This allows the outer ring to "run out" as compared to the crank shaft.

More likely that is the source of the constant adjusting.

There is one school of thought that say the tensioner will last the life of the car. However, that is most likely unrealistic. I suspect there is a way to measure the spring tension and determine if the spring is weak. However, the cost of the tool may exceed the cost of a new tensioner.

In my experience, the bearings give out before the spring thus rendering the question moot.

Thanks, I actually had my engine rebuilt 10k miles ago and had the crank shaft pulley/dampener replaced. I replaced everything below the intake manifold. The only thing i didn't replace was the tensioner. I'll take a short video of it today and see if maybe I'm over exaggerating the belt issue and it might just be normal use. I've never really looked at it before so i couldn't say.

 

[Kilgore Trout]

It is normal to see it move when the engine is running. At your mileage I would say it could fail at any time.