I was almost halfway through a 4hr drive when my serpentine belt ate it. Luckily I noticed quickly that the power steering was gone but the temp gauge was already at the 3/4 mark. I pulled over instantly on I-77. I have 115k miles on the truck, and I just had the belt changed for preventive maintenance 4 weeks ago. I didn't change the belt myself and my shop is pretty good and when I looked at it after it was changed, everything looked good like it was installed fine. I was able to spin the pulleys freely and they didn't appear to be loose. It's at some shop in the middle of nowhere because towing is expensive as hell even with 'roadside assistance'. So with the info above, do we think it was a defective belt or is something else going on? First thing I did was smell the oil fill chute, and thankfully nothing smelled burned.

Sounds like a faulty belt. What brand was the belt? I have completely reverted back to all oem replacement parts due to similar issues with non oem parts. That sucks hope everything ends up ok.

Sent from my SM-N970U using Tapatalk

If you were extremely unlucky it was a defective belt. Most likely it was installed improperly or they used the wrong belt. It’s really easy to miss the rib guidelines on the main pulleys. I’ve seen it happen a few times


Sent from my iPhone using Tapatalk

Can you tell by looking at the broken belt?

I'm not sure, and it's a good question. I dropped the keys in the overnight box at the shop where I left it and left the belt on the hood so they could see it, if that leaves any clues for them.

When you get a chance post a pic of the belt and also the part number on it


Sent from my iPhone using Tapatalk

X2 on above... I would say most likely it was installed improperly -miss the rib guidelines on one of the pulleys

Improper installation. Did you lose an idler pulley.

The tensioner should be changed as well as idlers too at 115K.....did the belt break, de-rail or a pully seize.......

Hard to imagine that a belt failed due to improper alignment after a month of use.

Had one belt fail on an SLK 280 just 4 miles from the shop where we had an AC Compressor replaced. The composite (plastic) pulley on the power steering pump right above the compressor just disintegrated and took the belt with it. I am pretty certain the AC mechanic was prying on the pulley which led to the failure. I replaced the power steering pump as the pulley was not sold separately, but the engine was dumping oil like a deer shot with a bow. Turns out that pieces of the shredded belt got wrapped up behind the crankshaft pulley and cut the crankshaft seal. I topped up the engine with oil and drove it 3 miles to the nearest independent Mercedes mechanic. We got very lucky.

Depending on brand, I believe the chance of getting a defective belt is 1 in 1000 or less. Based on the fact the vehicle was recently serviced points to something the shop probably did wrong. I am guessing they took a shortcut and pried on the belt to get it over a pulley. This likely damaged/weakened the structure of the belt, leaving mostly rubber to do the work. Over time, the rubber gives way and the belt disintegrates. Same as if you hit a pothole really hard with a tire, damaging the reinforcing belts. A few days/weeks later, the tire blows out when the rubber gives up.

IF IT AINT BROKE DON'T FIX IT

I bought a new serpentine belt for the mechanic that was installing a new Denso AC compressor in August 2018 on my 2005 SR5 4runner.

He handed it back and said the OEM belt on my 2005 SR5 with 140,000 miles was fine.

So much for preventative maintenance.

BTW.. No issues with the 2005 OEM belt or the new AC DENSO Compressor.

Serpentine belt is now 15 years old!

Amazon.com: ACDelco 7K834 Professional V-Ribbed Serpentine Belt: Automotive

I don't look at the belt for condition......I just change it every 5 years or at every 50K whichever comes first. It is up to 125 here and hotter on the road and can be almost 100 miles to the nearest service on the Highway so I don't risk stranding my Family, I just throw a $22 belt from E-Bay at it.

An update- There's no part number on the belt, and it likely came from Advance or Auto Zone. The shop that did the emergency work for me 2.5 hrs away said it's inconclusive to him as to what might have happened - improper installation or maybe even the wrong belt. He mentioned the idler pullies and the tensioner like you guys have and that they should be changed at some point, but that they also both were in good shape and he doubted that either one of those was the cause. Oh well, it all was a pain in the butt, but my shop has offered compensation. Like I said, they've done some great work for me, so something like this to happen is definitely an outlier. I'm chalking it up to s*** happens.