Best Serpentine Belt Tool Sets: 10 Sets Put Through Real-World Testing

Introduction

Working on a modern car can be genuinely difficult, especially if you have large hands. Engine bays are packed, and the serpentine belt tensioner is often buried behind covers and hoses. A serpentine belt tool, also called a drive belt or accessory belt tool, is designed for exactly this job: it releases spring-loaded tensioner pressure with the leverage and clearance a doubled-up wrench simply cannot offer. It is also a handy tool for fasteners in other hard-to-reach areas.

We compared ten sets to see which brand deserves your money.

How the Sets Were Tested

Every set went through the same battery of tests. First, the quality of the crowfoot wrenches was measured: weight, jaw opening, wrench width, and outer diameter. Second, a torque ridge calibration test measured the maximum torque each crowfoot could apply to a soft coupling nut before rounding it, with jaw stretch recorded. Third, a ratchet efficiency test counted how many right-to-left swings were needed for one complete rotation in a 50-degree workspace, followed by a back-drag test using a scale and fishing line.

Fourth, wrench-plus-socket stack height was measured for tight clearance situations, and each set was tried on real vehicles, including a couple of Chevrolets, a Buick, and a newer Toyota 4Runner where tensioner access is a real challenge. Finally, a brutal strength test loaded a 14 mm crowfoot onto a 14 mm Allen socket to see which wrenches survived, and a separate torture test pushed the 3/8-inch drives and ratchets to failure.

ABN Serpentine Belt Tool Set

The ABN set ran circles around the competition in most categories and finished with the best average rating. Its roughly 128-tooth ratcheting mechanism needed only 11.2 right-to-left swings for one full rotation, the best result, and its back drag of just 204 g was far ahead of every other brand. In the coupling nut torque test it reached 35.56 ft-lb, third place, with a very low 0.04 mm of jaw stretch, and it held on to third place in the 14 mm crowfoot strength test at 123.4 ft-lb.

On the tensioner, the two-piece handle adjusts to provide plenty of access swing, and it produced the best result in the slot clearance test at 1-5/8 inches. The ratchet and 15 mm socket survived the torture test at 276.50 ft-lb. Considering the price of under $50, this is the set to beat.

GearWrench Serpentine Belt Tool Set

GearWrench finished second overall with an average rating of 4.1. The set includes a long bar that holds sockets directly or attaches to the ratcheting wrench for maximum access, along with 3/8, 1/2, and 3/4-inch adapters, 13 to 19 mm sockets, and 13 to 15 mm crowfoots. It is made in Taiwan.

The 72-tooth ratchet needed 14.5 back-and-forth passes for one rotation, tying for third, and its 396 g of back drag was second best. In strength testing it was genuinely impressive: the 3/8-inch drive and ratchet survived 280 ft-lb of torque, the only full survivor in that test, and the ratcheting wrench and socket survived the socket torture test at over 277 ft-lb. The two-piece ratchet handle is a little clunky and not quite as precise as ABN’s, but it will definitely release belt tension. If the price is right, this is an easy recommendation.

Powerbuilt Serpentine Belt Tool Set

At $42, the Powerbuilt 13-piece set covers GM, Ford, Chrysler, Saab, VW, and Volvo applications and includes seven low-profile sockets plus a nicely made blow-mold case. It is made in Taiwan. The name fits: at 53.78 g, the crowfoot is the heaviest and thickest of the group, with more points of contact like a flare nut wrench.

That heft translated to the best torque result of the entire comparison at 73.1 ft-lb, with no jaw stretch at all. The trade-off is bulk. Wrench plus socket measured 26.9 mm, and on the 4Runner there simply was not enough swing space to release the tensioner. In the 14 mm strength test the wrench handle eventually broke at 162.475 ft-lb after about 0.22 mm of jaw stretch, though the ratchet kept working properly. A strong pick for brute force, less so for tight bays.

DNA Motoring Serpentine Belt Tool Set

The DNA Motoring kit is a 16-piece set with five sockets, three crowfoots, three bars, two square drives, a GM fan clutch kit, and two fix screws. It is made in China, and the two-piece non-ratcheting bar is not as efficient as a ratcheting wrench, but it will get the job done if you can keep it holding the socket.

Its torque performance was surprisingly strong, finishing second in the coupling nut test at 50.3 ft-lb and second in the slot test at 1-3/4 inches. However, the 14 mm crowfoot was too small to fit the Allen socket without being pounded on with a hammer, and it finally let go at 148.16 ft-lb with the socket and wrench destroying each other. The ratchet-side test was worse: it failed at only 141.5 ft-lb, last place, and is best described as a light-duty tool.

Performance Tool Serpentine Belt Tool Set

At $44, the Performance Tool set is the most comprehensive tested, with 16 pieces including a fan clutch removal kit and two different extensions for hard-to-reach areas. It is made in China.

Where this set shines is clearance: wrench plus socket measured just 21.03 mm, the best of any set, and its adjustable two-piece handle offers ample access and swing to release belt tension on difficult vehicles. In the coupling nut test it reached 35.49 ft-lb for a strong second place, though the 12.98 mm jaw opening is on the narrow side. Durability was mixed: the 14 mm crowfoot’s lower jaw broke at just over 104 ft-lb, and the wrench ran out of performance around 297.7 ft-lb in the socket torture test. Good value for access, with reservations on strength.

Billy Tools Serpentine Belt Tool Set

The Billy Tools set at $40 combines a ratcheting wrench with low-profile sockets and extensions, including a 14-inch extension arm, a 19 mm and 22 mm female ratchet drive, and square adapters. It is made in China. The 72-tooth ratchet needed 11.7 swings for one rotation, second best, and the two-piece handle adjusts to provide plenty of swing on the 4Runner.

Its crowfoot had the tightest fit of the group at 13.1 mm and the smallest outer diameter at 25.15 mm, and the wrench-plus-socket stack came in under 26 mm. Torque was third place at 26.4 ft-lb, but with the most jaw stretch at 0.14 mm. Durability was a bright spot: the 3/8 drive broke at a respectable 201.1 ft-lb, and the ratchet and sockets survived the torture test at over 280 ft-lb. One of the most durable budget options.

Ares Serpentine Belt Tool Set

At $55, the Ares 15-piece set covers 13 to 19 mm sockets, 13 to 15 mm crowfoots, quarter-inch through 3/8 and 1/2-inch adapters, and includes a reversible ratcheting wrench. It is made in Taiwan.

The 72-tooth ratchet tied for third in the swing test at 14.5 passes, but 534 g of back drag made it less pleasant in tight spaces, and its wrench positioning was not as efficient as ABN’s for maximizing swing. The crowfoot is narrow at 5.9 mm, which helps in confined spots, but it rounded the coupling nut at 29.68 ft-lb and is clearly made of a softer metal, with the worst jaw stretch of the group at 0.86 mm. On the plus side, the ratchet broke at 240.3 ft-lb, a very good performance for a budget 3/8-inch drive. Decent, but outclassed by ABN at a lower price.

Harbor Freight Icon Serpentine Belt Tool Set

The Harbor Freight Icon set costs $70 and includes 13, 14, and 15 mm crowfoots with 3/8 and 1/2-inch square drives. Its crowfoot performed reasonably in the coupling nut test at 27.94 ft-lb with only 0.04 mm of jaw stretch, which was good for eighth place.

The ratchet is the problem. With only 21 teeth, the low tooth count needed 21.5 swings for one rotation, with just one gear tooth advancing per swing, and back drag measured a stiff 1,552 g, more than twice any other brand. It lacks swing space on the 4Runner unless you attach the extra handle. In strength testing it failed to impress, letting go at 97.29 ft-lb in the 14 mm test with heavy jaw damage, and the ratchet suffered catastrophic damage at around 128 ft-lb. Hard to recommend at this price.

OTC Serpentine Belt Tool Set

The OTC set also costs $70 and includes 13, 14, and 15 mm crowfoots, built-in 13 and 15 mm 12-point wrenches on the handle, and 3/8 and 1/2-inch square drives. It is made in Taiwan.

The crowfoot is very slim at 5.79 mm wide, and jaw stretch was a low 0.04 mm, but torque at 27.16 ft-lb was disappointing for a set at this price, and it finished last in the 14 mm crowfoot strength test with an early knockout at 87.9 ft-lb and 0.7 mm of jaw growth. The 3/8 drive failed at 174 ft-lb, behind even the $20 Pittsburgh. The two-piece handle does provide plenty of swing space on real vehicles, but the overall durability does not match the price tag.

Pittsburgh Serpentine Belt Tool Set

At just $20 from Harbor Freight, the Pittsburgh set claims to pay for itself ten times over the first time you use it. It fits idler pulleys requiring 15 mm or 18 mm hex or 3/8 or 1/2-inch square drives and includes 13, 14, and 15 mm crowfoots. It is made in China.

Performance matched the price. The crowfoot rounded the coupling nut at 28.74 ft-lb with 0.07 mm of jaw stretch, the 14 mm crowfoot is notably soft and expanded to almost 15 mm under load, and the 3/8 drive broke free at 186.8 ft-lb. Without a ratcheting wrench and with no low-profile sockets, wrench plus socket measured 34.43 mm, and on the 4Runner it simply lacked the range of motion to release the belt. As a very light-duty emergency tool it works, but nothing more.

All Tools Serpentine Belt Tool Set

At $28, this 8-piece universal 3/8 and 1/2-inch drive set provides the leverage and clearance to release spring tension and move the tensioner pulley, covering 15, 16, and 18 mm hex and square drives. It is made in China.

Its main advantage over the Pittsburgh is a much lower profile: wrench plus socket measured 27.4 mm, about 7 mm slimmer, which helps in tight spaces. Everything else tracked closely with the Pittsburgh. The crowfoot rounded the nut at 25.63 ft-lb with 0.09 mm of jaw stretch, the most of any set tested here, and the 3/8 drive failed the same way at 156.43 ft-lb. Like the Pittsburgh, it had insufficient swing space on the 4Runner. An affordable step up in clearance, but still light duty.

Buying Advice for Tight Engine Bays

If you mostly work on modern front-wheel drive imports where tensioner access is the real challenge, ratchet efficiency and stack height matter more than raw strength. The ABN’s efficient ratchet and two-piece handle let the wrench achieve maximum swing, which is why it earned the best possible access rating. The Billy Tools, Performance Tool, Ares, and GearWrench sets all managed the same job with varying degrees of finesse, while the Pittsburgh, All Tools, and Powerbuilt sets struggled on the same vehicle for lack of swing space.

If durability is your priority, the Billy Tools, ABN, and GearWrench sets survived the torture test at well over 250 ft-lb. If you need to break loose seriously tight fasteners, the Powerbuilt crowfoot’s 73.1 ft-lb result is in a class of its own, provided you have the room to use it.

Conclusion

The ABN set is the overall pick: the best average finish across every test, a superb 128-tooth ratchet with minimal back drag, low jaw stretch, and a price under $50. GearWrench is a close second and the only set whose 3/8 drive survived the full 280 ft-lb torture test, making it a smart buy if you find it at a good price. Budget shoppers should look at Billy Tools for durability or Powerbuilt for raw strength, while the Pittsburgh and All Tools sets only make sense as cheap backups for occasional use.