Snapped Serpentine Belt - Simple or more to the mystery?

[gbaker]

Hi everyone, 2008 T4R, V8, only about 110k miles, but very rusty, NY vehicle. I drive it less than 2000-3000 miles per year. It's our 3rd vehicle that I use to plow, get to work on bad days, and enjoy some summer camping trips. A reputable local mechanic did the Timing belt service in 2020 and replaced the idler pulleys, tensioner, water pump, drive belt, housing assembly and thermostat at the time.

It has been extremely cold lately in NY, well below 0 with wind chill. This morning I remote started it, went out to drive it, and noticed when I got in, it wasn't nearly as hot as I expected, and when I put it into drive, I could barely turn the steering wheel and noticed the red battery light on that means there is an issue with the charging system of some sort. I backed it up, parked it, and went to work in a different vehicle.

I googled a bit during the work day, got home, and viola, found the snapped serpentine belt. I attached a few pics. Idk if this is weird, but I smelled the broken areas and it has a stronger distinct burnt rubber smell than non-ripped areas of the belt. Here's my big question, can I just buy a new serpentine belt and pop it on, or should I be checking to see if there is something else frozen that caused the tension and thus the break? I don't know much about DIY vehicle work, but I'm trying to learn, so I appreciate the help!

 

[AuSeeker]

The smooth side of that belt looks a bit worn, possibly because any of the pulleys/bearings being worn or more likely frozened/seized, or it could just be the belt has seen better days.

Check the bearings on both the idler and tensioner pulleys, if the both turn freely and no noise I would just put a new belt on and drive it.

Also check the alternator, power steering pump and anything else driven by the belt for the same.

If either or both of the bearings or other belt driven accessories are stiff/frozen or noisey, replace as necessary and put on a new belt.

 

[gbaker]

The smooth side of that belt looks a bit worn, possibly because any of the pulleys/bearings being worn or more likely frozened/seized, or it could just be the belt has seen better days.

Check the bearings on both the idler and tensioner pulleys, if the both turn freely and no noise I would just put a new belt on and drive it.

Also check the alternator, power steering pump and anything else driven by the belt for the same.

If either or both of the bearings or other belt driven accessories are stiff/frozen or noisey, replace as necessary and put on a new belt.

Thank you for this. Weather has been miserable and I don't have a garage, so haven't been able to troubleshoot further yet. But, should all of the pulleys, pumps, and bearing spin freely by hand, or do some of them need power to spin?

 

[Hungryhawk]

You can spin the pullys by hand. Also I would feel for any in/out play/ movement.
Feel for any unusual surface compared to other pullys. Unusual surface might be the place it broke? All pullies should be noise free and silky smooth.
Any idea how old the belt is?
I have run belts past a prudent lifespan and usually when you bend it backward you can see cracks in the ribs.

 

[AuSeeker]

Thank you for this. Weather has been miserable and I don't have a garage, so haven't been able to troubleshoot further yet. But, should all of the pulleys, pumps, and bearing spin freely by hand, or do some of them need power to spin?

Everything should turn/spin smoothly and without resistance, some of the pulleys have a smooth surface and should be smooth and free from rust and roughness, the other pulleys will have ridges that the grooved side of the belt engages/rides into, the only pulley that will not turn is the crankshaft pulley at the bottom of the engine, it's the pulley that powers/drives all the other pulleys.

Be sure to note how the belt is routed before removing it, there should be a diagram on how it routes under the hood somewhere, if you don't see that diagram take photos or draw your own diagram before removing the old belt!

Also most auto parts stores will print out the diagram for the belt if you need it.

 

[4R005]

Thank you for this. Weather has been miserable and I don't have a garage, so haven't been able to troubleshoot further yet. But, should all of the pulleys, pumps, and bearing spin freely by hand, or do some of them need power to spin?

The alternator pulley ( located below PS pump ) will be hard to reach from above since there are rad hose, air intake pipe etc in the way. Best way is to remove front skid plate which will expose the Alt and AC pulleys for examination. I shred my serpentine belt a few years back when the Alt bearing seized. Tip: with the broken belt you may be able to snag just the Alt pulley from above and see if pulley will spin freely. Regardless, you'll need a new belt and when installing it, you'll need a 14 mm socket ( a box wrench of similar size worked great for me ) and you turn the tensioning pulley bolt counterclockwise ( it's a lefthand thread so no danger of it coming loose) to move pulley for maximum slack to mount new belt on. Happy wrenching.

 

[Drcoffee]

The serp belt should last 80-100,000 miles before failing. You have only 8,000-12,000 miles on it. With that mileage you should still see the belt info printed on the smooth side of the belt. I dont see it at all, but you may have missed it in your pics. What most people dont know about serp belts is that a new belt has shallow grooves and worn has deep grooves. Your belt shows deep grooves and looks old and dry. Looking like they reinstalled the old belt in 2020. You need to see if the timing belt was done at all. If that belt breaks you could be looking at a bigger expense. Also, if they changed the pulleys, they should be shiny with no rust. If they look old, they probably are. Put a new serp belt on and take it to another shop for inspection. See if the work you paid for was actually done.

 

[gbaker]

Thanks for all the help. It took me about 3 hours of work, and a few frustration breaks, but I finally got the new belt on. Taking the coolant overflow container off helped a lot too. If I had to do it again, I might take that thick coolant hose off too, since I didn't realize it was blocking the full motion of the tensioner pulley for the longest time. The $20 flat serpentine belt toolkit from harbor freight also helped a lot too as compared to using a breaker bar which I tried first. I also used it to push the belt around a bit from the bottom and top in the tight spots. I'm sure if I had to do it again, it'd take 30 mins instead of 3 hours, but that's how we learn.

It starts and runs well with no dash lights. The alternator pulley (idk if that's the right word) spun a bit harder than all of the others, but it definitely was not frozen. So, feeling good at the moment!

 

[Drcoffee]

LOL EVERY JOB AROUND THE MOTOR IS EASIER WITH THE SKID PLATE OFF, BUT i hate taking it off.