2006 tacoma 4.0 serpentine belt/tension pulley

Ok guys, I have an 06 Tacoma double cab 4x4 with 4.0 engine. I am the original owner and the truck now has about 147,000 miles on it. 2 weeks ago I had the local Toyota dealer replace the front engine seal and harmonic balancer/lower pulley as I thought an axle seal was leaking and I was too lazy to change it myself. Turns out it was the engine seals so I was wrong. A week later I replaced the drive belt (2nd new one since I purchased the truck with 2 previous belts kept under the seat as spares) with a new Duralast belt from Autozone. This weekend I took the family for a drive down to Bolivar peninsula and then drove along the beach to Winnie, TX., then around through Anahuac, TX., west on I-10, and then back to my house. When I got home I smelled oil and checked under the vehicle and noticed a bad oil leak and the new Duralast serpentine belt had lost the edge closest to the engine. I talked to Autozone manager and got a new belt (not a Duralast) put the belt on and took the truck back to the dealer to find the leak. Turns out the new belt had shredded off the edge of the belt and that piece of belt was pulled into the new front seal of the engine. The reason (per dealer) why the belt had shredded was that the tensioner pulley had twisted a bit due to age and tension of the drive belt. The little bit of twist caused the drive belt to hang over the engine edge of the tensioner pulley and the belt had failed along the edge that hung off of the pulley (no noticeable while the engine was idling in my driveway).

My guidance to fellow Tacoma owners would be to replace the tensioner arm/pulley at about 100,000 miles if you haven't already. I did change the idler pulleys at about 100,000 but I did not change the idler arm itself.

 

Did you use Gates brand pulleys by any chance? I just purchased the Gates brand pulley for the tensioner and noticed it is not exactly a match for the factory pulley. It sticks out forward about an 1/8" more than the factory pulley and allows the belt to over hang on the engine side and would do exactly what you described. I would warn against using this brand pulley on the tensioner.

 

I think the bushing needs to go on the outside against all common sense. But when I replace my Tensioner pulley soon (I'm at 195k now) I am going OEM because I've had that issue on other idlers.