Simple question about belts

Where are you going to buy the belt? They should be able to tell you, or you'll have to tell them which belt(s) you need, in which case you'll have already answered your own question. Anyway, I'm betting they're different, can you find part numbers on them?

 

I doubt you need to carry a tensioner. They go for a very long time and will give you ample warning of their demise if you keep an eye on them. But at 7 years they may be at the end of their lifespan. Just give the parts man the last 8 of your truck's vin and that's all he'll need to find any part on your truck unless it's been modified. In fact just memorize those 8 letters/numbers because at 7 years you'll start needing them.

If you look at the rear of the sleeper on the cab where the airbags are you'll see the number stamped along the big brace that spans the airbags. Or on the left frame rail ahead of the firewall.

 

Carry the tensioner. Mine gave no warning. When I parked the truck it was fine no charging probs no belt slipping. Started up the next morning. Was not charging. Opened the hood broken tensioner. 2007 386 Pete isx 550.

 

they are not the same even though they look like they are.Gates part#38501 and #38503.

 

A better plan is to just change them before they fail. I changed my belts around 300K and then again at around 600K along with the tensioners when I had my radiator replaced. There was no savings in reusing old parts at that point, the tensioners were easily accessible and had been noisy for a while.

 

Any signs of cracks including spider cracks or frayed edges go ahead and change your belts. On occasion go ahead and put a wrench to the tensioner and see how much tension it has. It should take some muscle to move it. The main thing that wears on a tensioner is the bearing. You might be able to wiggle the pulley a hair, you might see it wobbling with the engine running, it might turn super shiny from the belt slipping, it might make noise like bob says from being dry or you can feel it after shutting the engine off. Worn bearings produce heat and would be abnormally hot. There are warning signs if you look carefully. They just don't go out overnight. The same with the idler pulley if it has one. If you change one change the other. Not all the time you have to change the whole tensioner. If it has good spring strength then change just the pulley which has a new bearing in it.

It's good to carry spare parts but one can fill their truck up with spare parts. Belts I would carry but a tensioner I would not.

 

Nothin wrong with carrying spares of parts that commonly fail. Hell a belt and tensioner could save you the 350.00 it cost to get mine fixed in a customers parking lot.

 

Do what is failing in these? Is it the bearing in the roller or the ability to keep tension?

Mine got noisy but I left them for a while then during a pre trip I noticed the wheel was not sitting square on the belt. I had my radiator replaced that day do I asked them to replace the tensioners at the same time.

Maybe on some trucks the tensioner isn't as visible ?