If your TJ's belt is older than five years or you can see cracks across the ribs when you flex it, replace it before it strands you — total job is under an hour with one wrench.
The TJ runs a single serpentine belt driving the alternator, power steering pump, water pump, A/C compressor (if equipped), and on some years the idler. A snapped belt kills charging and steering at the same time, and on the 4.0L it also kills the water pump, so an overheat is minutes away. Belts crack with age more than mileage — a garage-queen TJ with 30k on the clock and 10 years on the belt is as likely to grenade one as a daily driver.
Part numbers depend on year and accessories. For 2000–2006 4.0L with A/C, the Mopar belt is 5281668AA. The Gates equivalent is K060910 (six-rib, ~91" effective length). For 4.0L without A/C, use a 75" six-rib (Gates K060749 or similar). For the 2.5L four-cylinder, length differs again — confirm by VIN at Gates.com or measure your old belt before buying.
The tensioner is a spring-loaded pulley on the driver's-side front of the engine. Rotate it counterclockwise with a 1/2" breaker bar or a dedicated serpentine belt tool to release tension. Slide the old belt off, route the new one according to the diagram on the radiator support (or photograph the old routing before removal — this is the single most common mistake). Let the tensioner spring back against the new belt. Done.
While the belt is off, spin every accessory pulley by hand. Any roughness, wobble, or grinding means a bearing is on the way out — tensioner, idler, or water pump are the usual suspects. Replace anything that doesn't spin clean. A fresh belt on a dying idler will tear itself up in months.
| Part | Vendor | Est. price |
|---|---|---|
| Mopar Serpentine Belt 4.0L w/ A/C | Mopar | ~$38 |
| Gates K060910 Micro-V Belt (97-02 4.0L) | Gates/RockAuto | ~$24 |
| Goodyear/Continental serpentine belt equivalent | AutoZone | ~$28 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.