Updated April 2026
Drive Belt, AC Belt, Alternator Belt: They Are All the Same Serpentine Belt
On any vehicle made after approximately 1990, the serpentine belt, drive belt, accessory belt, AC belt, alternator belt, fan belt, and power steering belt are all the same single belt. One belt drives everything. If you are searching for any of these terms, you are looking at the same repair at the same cost.
The Short Answer
Modern vehicles use one single long belt that wraps around every engine accessory. Before the serpentine belt was adopted in the late 1980s and early 1990s, each accessory had its own separate V-belt. Today, the serpentine belt does the job of what used to be 3-4 separate belts.
Regardless of what you call it, the replacement cost is the same: $100-$250 for the belt, or $150-$400 with the tensioner.
Why It Has So Many Names
| Name | Why It Is Called That |
|---|---|
| Serpentine beltStandard term | Named for its serpentine (snake-like) routing path winding through multiple pulleys. |
| Drive beltStandard term | It drives all engine accessories from the crankshaft pulley. |
| Accessory beltStandard term | It powers the engine accessories (alternator, AC, power steering, water pump). |
| AC belt | It drives the AC compressor. Searchers often look for this when their AC stops working. |
| Alternator belt | It drives the alternator. Searchers often look for this when the battery light comes on. |
| Fan belt | On older vehicles, the belt drove a mechanical cooling fan. Modern vehicles use electric fans, but the name persists. |
| Power steering belt | It drives the hydraulic power steering pump. Searchers look for this when steering becomes heavy. |
All seven names refer to the same single belt on modern vehicles. Auto parts stores, shops, and manufacturers use "serpentine belt" as the standard industry term.
The Exception: Older Vehicles With Separate V-Belts
Some vehicles manufactured before 1990 (and a few outliers into the mid-1990s) use separate V-belts for individual accessories instead of a single serpentine belt. These V-belts are thinner, narrower, and each one drives just one accessory. A vehicle with separate V-belts might have three or four belts: one for the alternator, one for the AC compressor, one for the power steering pump, and possibly one for the water pump or air injection pump.
How to tell which you have: Open the hood and look at the front of the engine. If you see one wide, flat belt with multiple ribs on the inside surface weaving through many pulleys, that is a serpentine belt. If you see multiple thin, V-shaped belts each running between only two pulleys, those are V-belts.
Individual V-belt replacement costs $50-$120 per belt including labor. If multiple V-belts need replacing, the total can exceed a serpentine belt replacement because each belt is a separate installation.
How the Serpentine Belt System Works
The serpentine belt starts at the crankshaft pulley, which is the lowest pulley at the front of the engine, directly driven by the engine. From there, it winds through each accessory pulley in a specific path determined by the engineers who designed the engine layout.
Ribbed side contact: The grooved inner surface of the belt grips the grooved pulleys of the alternator, AC compressor, power steering pump, and sometimes the water pump. This is where power is transferred.
Smooth backside contact: The flat outer surface of the belt runs against smooth idler pulleys and sometimes the smooth side of the water pump pulley. These pulleys guide the belt around corners in the routing path.
Tensioner: A spring-loaded tensioner pulley maintains constant pressure on the belt, automatically compensating for belt stretch and wear over time. The tensioner is what keeps the system working without manual adjustment.
When Manufacturers Switched to Serpentine Belts
| Manufacturer | Approximate Transition |
|---|---|
| GM (Chevrolet, GMC, Buick, Cadillac) | Mid-1980s to early 1990s |
| Ford | Late 1980s to early 1990s |
| Chrysler (Dodge, Jeep, Ram) | Late 1980s to mid-1990s |
| Toyota | Early 1990s |
| Honda | Early to mid-1990s |
| Nissan | Early 1990s |
| BMW | Late 1980s |
| Mercedes-Benz | Late 1980s to early 1990s |
| Subaru | Mid-1990s |
| Hyundai / Kia | Mid-1990s |
By 2000, virtually every new vehicle sold in the US used a single serpentine belt. If your vehicle is a 2000 model year or newer, it almost certainly has a serpentine belt.
Does the Serpentine Belt Affect the AC?
Yes. The serpentine belt drives the AC compressor on virtually all vehicles. When the belt slips or breaks, the AC compressor stops spinning and AC output stops immediately. This is why "AC belt" is a common search term. People notice the AC stopped working and search for the belt that drives it.
If your AC has suddenly stopped working and you also hear a squeal or notice other belt symptoms (heavy steering, battery light), the serpentine belt is very likely the cause. A slipping belt often affects the AC first because the AC compressor has the highest load of any accessory on the belt system.
Related: AC Compressor Replacement Cost covers the scenario where the compressor itself has failed rather than the belt.