On the XA50 RAV4 with the 2.5L A25A-FKS, the accessory belt is a straightforward automatic-tensioner job, but Toyota buried it behind the right front wheel. Nearly all the work is removing the engine undercover and inner fender liner; the belt itself takes two minutes once you can reach the tensioner with a long 3/8 in bar. There is no belt routing sticker you can count on, so take a photo before the belt comes off.
The big thing people get wrong is the hybrid. RAV4 Hybrid and Prime use the A25A-FXS with an electric water pump, electric A/C compressor and motor-generators instead of an alternator — there is no accessory drive belt to replace, and a squeal on one of those cars is coming from somewhere else. The second most common mistake on the gas car is leaving one rib hanging off the edge of a pulley after installation, which destroys the new belt in short order.
| Item | Type | |
|---|---|---|
| Floor jack 2 ton minimum, low profile Lift the right front corner to reach the crank pulley area and fender liner. | Required | shop |
| Jack stands 2 ton pair, under the pinch weld / subframe Hold the car safely while you work in the wheel well. | Safety | shop |
| Wheel chocks Behind rear wheels Stop the car rolling while the front is jacked. | Safety | shop |
| Lug nut socket 21 mm, 1/2 in drive, thin-wall Remove the right front wheel for side access to the belt. | Required | shop |
| Breaker bar 1/2 in drive, 18-24 in Loosen lug nuts before lifting. | Required | shop |
| Socket wrench set 3/8 in drive ratchet with 10 mm and 12 mm sockets Engine undercover and fender liner bolts on the XA50 are 10 mm heads; a few splash shield bolts are 12 mm. | Required | shop |
| Plastic trim clip / panel removal tool Nylon pry set The undercover and inner fender liner use push-pin retainers that break if levered with a screwdriver. | Required | shop |
| Phillips screwdriver #2 Some fender liner clips have a screw-type center. | Recommended | shop |
| Serpentine belt tensioner tool Long-handle 3/8 in drive belt tool kit with 14 mm/15 mm crowfoot and socket adapters Gives the reach and leverage to rotate the tensioner in the tight space behind the engine mount. | Required | shop |
| 14 mm socket 6-point, 3/8 in drive (some tensioners take 15 mm) Fits the tensioner pulley center bolt to swing the arm and release belt tension. | Required | shop |
| Breaker bar or long ratchet 3/8 in drive, 15-18 in Extra leverage on the tensioner if you are not using a dedicated belt tool. | Required | shop |
| Extensions and wobble/swivel 3/8 in drive, 3 in, 6 in and universal joint Reaching the tensioner past the engine mount and coolant hoses. | Required | shop |
| Inspection mirror and flashlight Telescoping mirror, LED work light Confirm every rib is seated in every pulley groove before starting the engine. | Recommended | shop |
| Belt routing diagram Photo taken before removal, or FSM diagram The XA50 may not have an underhood routing sticker — your own photo is the safest reference. | Recommended | shop |
| Torque wrench 1/2 in drive, 20-150 ft-lb Torque the wheel lug nuts correctly on reassembly. | Required | shop |
| Serpentine belt 6-rib (6PK) belt for 2.5L A25A-FKS — match by VIN at the counter The replacement belt; gas models only. | Parts | shop |
| Belt tensioner assembly Automatic tensioner for A25A-FKS Optional: replace if the arm chatters, the pulley bearing is noisy or tension feels weak. | Parts | shop |
| Idler pulley If equipped on your build Spin-check when the belt is off; replace if rough or noisy. | Parts | shop |
| Brake cleaner or degreaser Aerosol, non-residue Clean oil or coolant off pulley grooves so the new belt does not slip. | Consumables | shop |
| Nitrile gloves and safety glasses Debris falls from the wheel well and the tensioner can snap back. | Safety | shop |
2.5L A25A-FKS (gas, FWD and AWD): one 6-rib serpentine belt with an automatic tensioner; 14 mm (some builds 15 mm) tensioner pulley bolt, 10 mm undercover and fender liner bolts, 21 mm lug nuts. 2.5L A25A-FXS (Hybrid, Hybrid Prime): no accessory drive belt exists — none of these tools apply. Lug nut size and torque are the same across the generation.
| Front wheel lug nuts | 76 ft-lb (103 Nm) |
| Engine undercover / splash shield bolts | Snug only, roughly 6-8 ft-lb (8-11 Nm) — verify in the service manual |
| Belt tensioner mounting bolts (if tensioner replaced) | verify in the service manual |
| Idler pulley bolt (if replaced) | verify in the service manual |
Fastener sizes here (10 mm covers, 21 mm lugs, 14 mm tensioner bolt) match Toyota's usual XA50 hardware, but tensioner bolts on this engine can be 15 mm depending on build date, so test-fit both before applying force, and verify undercover and tensioner torque values in the FSM.
No. The A25A-FXS hybrid engine uses an electric water pump and electric A/C compressor, and the motor-generators handle charging, so there is no accessory drive belt. Only the gas 2.5L A25A-FKS has one.
A 14 mm 6-point socket on the tensioner pulley center bolt covers most builds, with some taking 15 mm. Use a long 3/8 in drive bar or a dedicated serpentine belt tool with a swivel to get leverage past the engine mount.
You can sometimes wrestle the belt out from below with just the undercover off, but pulling the right front wheel and inner fender liner makes it far easier to see the routing and confirm seating. Budget the extra 15 minutes.
Toyota calls for inspection at regular services rather than a fixed replacement interval; most owners change it around 90,000-100,000 miles or sooner if there are cracks across the ribs, missing chunks, glazing or a chirp on cold start. Check the tensioner and idler at the same time.