On the DT-generation Ram 1500 this is a straightforward tensioner-and-swap job made awkward by packaging. The front of the engine is boxed in by the cooling module and fan, so most of your time goes into pulling the engine cover, intake duct and often the upper fan shroud just to get a breaker bar on the tensioner. Once you can reach the tensioner, the belt itself is off in two minutes.
The thing people get wrong is the belt itself. On eTorque trucks the accessory belt also has to start the engine through the 48-volt belt-starter-generator, so it is a specific heavy-duty construction — a cheap generic belt of the right length will chirp, slip during auto start/stop restarts, and fail early. Order by VIN. The second most common mistake is routing: eTorque and non-eTorque Hemis are not the same, so photograph the original and check the under-hood label before the old belt comes off.
| Item | Type | |
|---|---|---|
| Wheel chocks Truck stays on the ground for most of this job; keep it from rolling. | Safety | shop |
| Mechanic's gloves Protects hands from sharp pulley flanges and hot components. | Safety | shop |
| Socket set, metric 8, 10, 13, 15, 16, 18 mm, 3/8 in drive Air box/resonator screws, battery terminal, fan shroud bolts and tensioner/idler bolts. | Required | shop |
| Ratchet 3/8 in drive, 8-10 in General fastener removal for covers, shroud and intake ducting. | Required | shop |
| Breaker bar 1/2 in drive, 18-24 in Gives the leverage needed to swing the automatic belt tensioner off the belt. | Required | shop |
| Serpentine belt tool kit 3/8 in drive, with crowfoot sockets and long offset handle Reaches the tensioner in the tight space behind the cooling module, especially on the 3.6 and 3.0. | Required | shop |
| 18 mm socket 6-point, 1/2 in drive, thin wall Fits the 5.7 Hemi tensioner pulley center bolt to rotate the tensioner. | Required | shop |
| 15 mm socket 6-point, 3/8 in drive Tensioner pulley bolt on 3.6 Pentastar and idler pulley fasteners. | Required | shop |
| Extension set 3/8 in and 1/2 in drive, 3 in, 6 in, 10 in Clears the fan and radiator support to reach the tensioner. | Required | shop |
| Wobble/swivel extension 3/8 in drive Lets you reach the tensioner at an angle without pulling the cooling module. | Recommended | shop |
| Flat-blade screwdriver / trim tool set Plastic pry tools Pops the intake duct clips, push-pin retainers and engine cover without breaking them. | Recommended | shop |
| Long nose pliers Frees hose clips and helps guide the belt behind the fan. | Recommended | shop |
| Zip tie or bungee Hold the tensioner back or hold the new belt in place on a pulley while you route it. | Recommended | shop |
| Inspection light LED work light or headlamp The lower crank and A/C pulleys are nearly invisible without light. | Recommended | shop |
| Torque wrench 3/8 in drive, 10-80 ft-lb For re-torquing any tensioner, idler or shroud bolts you removed. | Recommended | shop |
| Belt tension/wear gauge Rib-wear gauge for 6-rib K-section Confirms the old belt is actually worn and the new one is seated in every groove. | Recommended | shop |
| 10 mm wrench or socket Disconnect the 12 V negative battery terminal before working near the eTorque belt-starter-generator. | Recommended | shop |
| Serpentine belt 5.7 eTorque, 3.6 eTorque and 3.0 EcoDiesel each use a different Mopar-specific belt; buy by VIN eTorque belts carry generator-start loads, so use the OE-spec belt, not a generic length match. | Parts | shop |
| Belt tensioner assembly Engine-specific; only if pulley is noisy or arm is weak A tired tensioner will chirp and shorten the life of the new belt. | Parts | shop |
| Brake cleaner or belt cleaner Aerosol Removes oil film from pulley grooves so the new belt does not slip or chirp. | Consumables | shop |
| Shop rags Wipe pulley grooves and any coolant or oil residue. | Consumables | shop |
5.7 Hemi eTorque tensioners generally take an 18 mm socket on the pulley center bolt and can often be reached from above with a long extension and swivel. The 3.6 Pentastar eTorque tensioner is typically 15 mm and sits low behind the cooling module, so an offset serpentine belt tool handle is close to mandatory. The 3.0 EcoDiesel is the tightest of the three: plan on a crowfoot/offset belt tool and, on many trucks, loosening or tipping the cooling module, and be aware some EcoDiesels run a separate secondary belt for an accessory.
| Belt tensioner assembly bolt to bracket (all engines) | verify in the service manual |
| Idler pulley bolt | verify in the service manual |
| Fan shroud / cooling module bolts | verify in the service manual (low value, plastic — snug only) |
| Battery negative terminal nut | verify in the service manual (approx. 5 ft-lb / 7 Nm) |
The 18 mm tensioner bolt on the 5.7 Hemi and 15 mm on the 3.6 Pentastar match the common sizes for these engine families, but Mopar changed tensioner suppliers within this generation, so test-fit 15, 16 and 18 mm before you commit, and verify all torque values in the FCA/Stellantis service manual for your VIN.
Use an OE-spec belt for eTorque. That belt transmits engine-start torque from the 48 V belt-starter-generator, and standard-duty belts slip and squeal under those loads. Order by VIN so you get the eTorque part rather than the non-eTorque length.
Most 5.7 Hemi tensioners in this generation use an 18 mm socket on the pulley center bolt with a 1/2 in drive breaker bar. Test-fit 15 and 16 mm too, since suppliers varied through the generation.
On the 5.7 you can usually work from above with a long extension and swivel. On the 3.6 and especially the 3.0 EcoDiesel most people remove the upper fan shroud or loosen the cooling module to get a tool on the tensioner and to snake the belt out.
The DT needs a battery-state relearn before it will re-enable auto start/stop. It is normal for the feature to be unavailable for some drive cycles; no scan tool or battery registration is required for a belt replacement.