- Safety first
- Park on level ground, engage parking brake, apply wheel chocks behind rear wheels, wear eye protection and gloves.
- Work with engine cool. Disconnect negative battery terminal to avoid accidental engine start or electrical shorts.
- Use a proper jack and jack stands if you must go under the vehicle; never rely on a jack alone.
- If any fastener feels seized, use penetrating oil and care — don’t apply sudden extreme force that can break bolts or tools.

- Tools required (detailed descriptions and how to use each)
- Ratchet and socket set (metric): used to remove splash shields, accessory brackets, and sometimes the tensioner bolt. Choose the correct socket size; push the socket fully onto the fastener and pull the ratchet handle steadily. Use long-handled ratchets for more leverage on stubborn bolts.
- Breaker bar (long non-ratcheting bar): used to apply higher leverage to loosen tight bolts or to move the belt tensioner on some models. Fit a socket on the breaker bar, place on the bolt, and push/pull slowly.
- Serpentine belt tool or long-handled 3/8" or 1/2" drive ratchet/extension: many Hilux tensioners need a long-handled tool to rotate the tensioner pulley to release belt tension. A dedicated serpentine belt tool is slim and fits tight spaces. Use it to rotate the tensioner in the direction indicated on the tensioner (usually clockwise or counterclockwise) and hold while slipping the belt off.
- Torque wrench (click-type, metric): ensures bolts are tightened to manufacturer torque specs (reduces risk of stripped bolts or parts failure). Set the required torque, snug the bolt, then apply until the wrench clicks.
- Combination wrenches (metric set): useful where sockets can’t reach. Use the correct-size wrench, pull the wrench toward you rather than push when possible for better control.
- Screwdrivers (Phillips and flat): remove clips, pry off covers or loosen hose clamps gently. Use the correct tip to avoid camming out.
- Pry bar / small flat bar: useful to gently move components or align belt on a pulley — use sparingly to avoid damage.
- Flashlight or work light: exposes pulley grooves and belt routing.
- Gloves and safety glasses: protect hands and eyes.
- Jack and jack stands (if splash guard or lower access required): lift vehicle safely and support on stands; never work under unsupported jack.
- Wheel chocks: prevent vehicle roll.
- Torque or impact rated tools optional: impact wrench can speed bolt removal (use with care).
- Pen and phone camera: document belt routing so you can re-route correctly.

- Useful extra tools (why they may be required)
- Serpentine belt tensioner tool set: needed if the tensioner is in a tight spot where a normal ratchet or breaker bar won’t fit. It simplifies releasing tension without removing nearby parts.
- Idler/tensioner pulley holding tool: helps prevent tensioner from snapping back while you work; reduces risk of injury and makes belt installation easier.
- Penetrating oil and small hammer: for frozen bolts; penetrating oil soaks, hammer taps can help free them. Use carefully to avoid damage.
- Replacement tensioner and idler pulley(s) and bearing puller (if replacing those parts): if pulleys are seized or bearings noisy you’ll need to remove and replace them; a puller helps remove tight pulleys.

- Parts you may need and why
- New serpentine/drive belt (required if old belt shows wear or per maintenance interval): belts age and crack, ribs wear, or they glaze — replace to prevent belt breakage and loss of charging/charging/AC/power steering.
- Tensioner assembly (recommended replacement if worn, noisy, or has excessive play): the spring or bearing can fail, causing poor tension and belt slip or premature belt wear.
- Idler pulley(s) (replace if bearing noisy or grooves damaged): bad pulleys can seize or misalign the belt.
- Alignment hardware/bolts (replace if threads damaged or bolts rounded): use correct hardware and torque.
- Manufacturer or high-quality aftermarket belts: Gates, Dayco, Conti are common. Buy correct belt length and rib count for your Hilux engine (check owner’s manual or parts lookup).
- Don’t use “belt dressing” — it’s a temporary fix and can cause contamination.

- How to identify the belt type and buy the right part
- Check under-hood sticker/diagram (often inside engine bay cover) for belt route and part number.
- If absent, note engine code and year (e.g., 2.7 petrol, 1KD-FTV diesel) and confirm belt part number with dealer or online parts lookup.
- Measure old belt length and rib count if needed; bring old belt to auto parts store to match.

- Step-by-step replacement procedure (basic sequence for a beginner)
- Prepare vehicle: park, chock wheels, disconnect negative battery, open bonnet, put on safety gear, position light.
- Photograph or sketch current belt routing: take clear photos from multiple angles. This is essential.
- Remove obstructing panels: if a plastic splash guard or undertray blocks access, support the engine bay as needed and remove the fasteners with ratchet/sockets or screwdrivers. Save fasteners in a tray.
- Locate the belt tensioner and identify rotation direction: inspect the tensioner pulley for an arrow or mark showing which way to rotate to relieve tension.
- Relieve belt tension: fit the correct size socket or belt tool to the tensioner square or bolt, rotate slowly in the indicated direction until slack appears, and slip the belt off one accessible pulley (usually easiest to remove from the alternator or AC pulley). Hold tensioner in the released position while removing the belt.
- Remove the old belt: with tension relieved, pull the belt off all pulleys and out of the engine bay. Compare it to the new belt to confirm length and rib count.
- Inspect pulleys and tensioner: spin each pulley by hand; note roughness, play, wobble, or noise. Check alignment and pulley grooves for glazing or debris. Replace any faulty pulley or tensioner.
- Install new belt: route the new belt per your photos/diagram around the pulleys leaving the tensioner pulley for last. Ensure ribs seat properly in each pulley groove.
- Re-tension: using the same tool, rotate the tensioner to allow the belt to slip over the tensioner pulley, then carefully release the tensioner so it applies tension to the new belt. Confirm belt is seated correctly on all pulleys and aligned.
- Double-check: confirm routing matches diagram/photos, check belt has about the same tension as a new belt should (no excessive slack). Spin the crank pulley by hand (if accessible) to ensure smooth run and that the belt stays seated.
- Reassemble removed parts: reinstall undertrays or covers, tighten fasteners to recommended torque if known, or snug then check later with torque wrench.
- Reconnect battery: reconnect negative terminal, secure.
- Start engine and observe: with engine idling, watch the belt and pulleys for a minute for correct tracking, unusual vibration, or noise. Turn off and recheck tension and fasteners.
- Final safety check: after a short drive, re-inspect for looseness, noises, or misalignment.

- How to use specific tools in-situation
- Using a breaker bar or ratchet on the tensioner: place the socket on the tensioner square or bolt head. Pull or push in the direction the tensioner requires. Keep your body out of the belt path; hold the tensioner and slip the belt off quickly then release the tensioner slowly.
- Using a torque wrench: set required torque, attach appropriate socket, tighten bolt until the wrench clicks. If you don’t know the torque, tighten snug and consult a repair manual or dealership for exact values before finalizing.
- Using a jack and stands: lift at manufacturer lift point, raise vehicle high enough for access, place stands under the frame or rated lift points, lower the jack until the vehicle settles on the stands, give a firm shake to confirm stability.

- Signs you must replace tensioner/idler (not just belt)
- Squealing, chirping, or grinding noises from pulleys.
- Visible wobble, play, or rough spinning when turning pulley by hand.
- Belt wearing unevenly, glazing, or slipping despite proper routing.
- Tensioner spring weakness (belt shows excessive slack).

- Common beginner mistakes to avoid
- Forgetting to document routing — this causes reinstall errors.
- Using wrong-size belt or wrong rib count.
- Not supporting vehicle properly when working underneath.
- Allowing tensioner to snap back uncontrolled — hold or secure it.
- Not inspecting pulleys — new belt on worn pulleys will fail quickly.

- Quick checklist before finishing
- Belt routing matches diagram/photo exactly.
- Pulleys spin smoothly, no play.
- All fasteners tightened and covers replaced.
- Battery reconnected.
- No unusual belt noise when engine runs.

- Recommended parts/brands
- OEM Toyota belt or quality aftermarket: Gates, Dayco, Conti. Match exact part by engine/year.
- Replace tensioner and idler pulleys if they’re noisy or older than the belt replacement interval — many mechanics replace tensioner and idler as preventive maintenance with a new belt.

- Disposal and cleanup
- Dispose old belt per local waste regulations.
- Clean tools, store fasteners and leftover parts, and note the date/mileage of replacement for future service records.

- Final safety reminder
- If any step feels uncontrolled or a fastener won’t budge, stop and use penetrating oil, the correct tool, or seek professional assistance. Improper removal or reinstallation can cause engine damage or injury.
rteeqp73

Tools & supplies
- New PCV valve (match VIN/engine) and any replacement O-ring/grommet or breather/oil-separator if used
- Small flat-blade screwdriver and Phillips screwdriver
- Pliers (needle-nose and hose-clamp style)
- 1/4" & 3/8" ratchets, extensions, sockets (8, 10, 12 mm common)
- Small pick or dental probe (for O-rings/grommets)
- Clean shop rags and paper towels
- Nitrile gloves, safety glasses
- Torque wrench (if you remove valve cover or bolts; 1/4" drive ok)
- Container for oil/old parts, disposable bags for contaminated rags
- Optional: hand vacuum pump (to test), compressed air (low-pressure blowout)

Safety precautions
- Work on a cold engine. Hot aluminum/plastic and pressurized systems cause burns.
- Park on level ground, engage parking brake. Chock wheels.
- Wear gloves and safety glasses. Keep rags away from ignition sources (oil soaked rags are combustible).
- Disconnect negative battery terminal only if you will be removing ignition coils or sensors; not strictly required for PCV swap but recommended if you’ll disturb wiring.
- Dispose of oil-soaked rags and old parts according to local rules.

Identify the PCV on a Hilux (general guidance)
- Petrol engines (e.g., 2.7 2TR-FE): PCV valve is usually on the valve cover or in a small rubber grommet on the top of the rocker/valve cover, with a vacuum hose to the intake manifold.
- Diesel engines (e.g., 1KD-FTV): Many use an oil-separator/breather assembly with a valve integrated; location is typically on or near the rocker cover and feeds the intake via a larger hose.
- If unsure, trace the hose from the intake manifold toward the valve cover/rocker cover — PCV / breather is at the end of that hose.

Parts required
- Correct PCV valve for engine (OEM or quality aftermarket).
- Grommet/O-ring if the PCV seals into a rubber grommet (replace if brittle).
- If Hilux model uses an oil-separator element, replace that if oil-soaked or cracked.
- New small hose clamps or replacement vacuum hose if the old is cracked.

Step-by-step replacement (typical petrol-style PCV on valve cover)
1. Prepare: let engine cool, wear PPE, chock wheels.
2. Remove obstructions: remove engine cover (snap-on) or any air intake ducting that blocks access. Use screwdriver/sockets as needed.
3. Locate PCV: find the small valve protruding from the valve cover with a vacuum hose attached.
4. Inspect: look for oil residue, cracked hose, brittle grommet. If oil-soaked or valve’s moving parts appear clogged, replace both valve and grommet.
5. Release hose clamp: use needle-nose pliers or flat screwdriver to loosen the clamp on the vacuum hose at the PCV valve end. For clamp pliers, squeeze and slide clamp back along hose.
6. Disconnect hose: twist gently while pulling the hose off the PCV valve. If stuck, use a twisting motion and a small flat screwdriver to pry carefully—don’t tear the hose or damage the valve cover.
7. Remove PCV: some PCV valves pull straight out from a grommet; others have a bayonet or clip. Pull straight while wiggling. If the PCV is threaded, use appropriate pliers or socket. Use pick to lift the old grommet out if replacing.
8. Clean seat: wipe the valve cover hole and mating surfaces with a rag. Use low-pressure compressed air to clear dirt so nothing falls into port.
9. Install new grommet/O-ring: if supplied, lubricate lightly with clean engine oil and press into valve cover hole until seated flush.
10. Install new PCV valve: push the valve into the grommet until it snaps/seats. Ensure orientation correct (check part: vacuum side to intake).
11. Reattach vacuum hose: push hose onto PCV valve nipple and secure clamp. Ensure hose is routed as before — no kinks.
12. Reassemble intake/engine cover: reinstall removed parts. If you removed ignition coils, tighten to specified torque (manufacturer’s spec).
13. Start engine: run for a few minutes, check for vacuum leaks, listen for hissing, inspect for oil leaks around the valve and hose.
14. Test: with the engine idling, remove the PCV quickly (if accessible) and cover the hole with finger — you should feel vacuum if working. Or use a hand vacuum pump to confirm valve holds vacuum. Replace immediately after test.

Step-by-step replacement (diesel oil-separator type)
1. Prepare as above and remove plastic covers/airbox to expose breather assembly.
2. Remove hose clamps and vacuum/breather hoses from the oil-separator assembly.
3. Unbolt the oil-separator (often 2–4 small bolts 8–10 mm). Support assembly as you remove bolts.
4. Remove separator and inspect for oil pooling; if heavily contaminated, replace separator element or entire assembly.
5. Remove old PCV valve or internals, replace with new part and grommet. Clean sealing surface on the valve cover.
6. Reinstall separator and hoses, torque bolts to light spec (usually 6–10 Nm; avoid over-torqueing plastic).
7. Reconnect all hoses and start engine; check for leaks.

How each tool is used — short notes
- Ratchet/sockets: remove any bolts holding intake components, separator or valve cover bits. Use extension to reach recessed fasteners.
- Screwdrivers: pry off clips, loosen hose clamps, remove engine cover fasteners.
- Pliers (needle-nose): pull off small hoses and clamps; hold small components.
- Hose-clamp pliers: compress and slide spring-type clamps on vacuum hoses.
- Pick/dental probe: lift old O-ring/grommet without damaging mating surfaces.
- Torque wrench: tighten bolts (valve cover, separator) to specified torque to avoid cracking plastic/warping metal.
- Vacuum pump: test valve by pulling vacuum; PCV should hold and let vacuum through one-way only.
- Compressed air (low pressure): blow out dirt around port before inserting new PCV, not into engine.

Common pitfalls & how to avoid them
- Using wrong part: match part number to VIN/engine. Wrong flow direction or dimensions lead to vacuum leaks.
- Damaging brittle grommet: remove slowly; replace grommet rather than reusing old one.
- Breaking plastic housings: don’t overtighten bolts or use excessive leverage. Use correct socket sizes.
- Not cleaning mating surfaces: dirt falling into the crankcase/inlet causes contamination — clean first.
- Reusing cracked vacuum hose: replace if brittle; a small leak causes rough idle/PCV failure symptoms.
- Not seating PCV fully: ensure clicking/locking engagement; test for vacuum after install.
- Overtightening hose clamps: can cut hoses; use correct clamp tension.
- Forgetting to route hoses correctly: wrong routing can create kinks or heat exposure.
- Forgetting to inspect oil separator on diesels: a clogged separator causes excess oil consumption and smoke.

Diagnostics quick checks (before replacing)
- Shake test: remove PCV (if accessible). A good valve often “clicks” or has a loose internal plunger; if stuck solid, replace.
- Vacuum/hand pump: valve should hold vacuum on one side and not on the other (one-way).
- Symptoms of bad PCV: oil consumption, oil in intake, rough idle, hissing, check engine light (P0171/P0174 can be related to vacuum leaks).

Final notes
- Replace PCV at recommended intervals or if symptoms present. On diesels, replace the entire breather/separator assembly more often if oil starts pooling.
- Keep used parts/oil-contaminated rags sealed and dispose properly.

Done.
rteeqp73

Overview (theory first)
- What the drive/serpentine belt does: a single multi-rib belt transmits engine crankshaft torque to accessories — alternator, water pump (on some engines), power steering pump, A/C compressor and sometimes vacuum pumps. Ribs increase contact area and wrap angle to transmit torque by friction. Proper belt tension and pulley alignment prevent slip, noise and wear.
- Failure modes: cracking, rib chunking, glazing, oil/antifreeze contamination, rib separation, stretching, worn bearings on idlers/tensioner causing misalignment. Symptoms: squeal/ chirp, accessory failure (no charging, overheating, hard steering, A/C loss), visible damage, or belt off/pulled into engine.
- How replacement fixes the fault: a new belt restores correct thickness, rib shape and friction surface; a new or serviced tensioner restores correct tension and damping; replacing worn idlers/pulleys restores alignment and smooth rotation. Together they eliminate slip, restore drive of accessories and prevent belt breakage.

Ordered procedure (with brief theory for each step)
1) Prepare the vehicle and safety
- Park on level ground, engage parking brake, chock wheels, engine cold. Disconnect negative battery terminal if you will be working near electrical connectors or the alternator (prevents shorts).
- Theory: prevents accidental startup and electrical shorting while you manipulate the belt and pulleys.

2) Locate belt routing diagram and inspect current belt
- Find the routing diagram (sticker under hood or in service manual) and photograph it if absent. Visually inspect the belt for cracks, glazing, rib loss, oil contamination; spin exposed pulleys by hand to listen for rough bearings.
- Theory: correct routing and wrap angles are essential. Inspection identifies whether only the belt or also pulleys/tensioner need replacement — replacing only the belt while a bearing is bad is a short-term fix.

3) Gather tools and replacement parts
- Required: correct replacement belt (exact OEM or correct size/rib count), possibly replacement tensioner/idler(s), breaker bar or belt tensioner tool/special socket, socket set, torque wrench.
- Theory: tensioning devices are spring-loaded; some require specific tools to move them safely. Using the correct belt avoids slippage or excessive tension.

4) Relieve belt tension and remove old belt
- Locate the automatic tensioner. Using the appropriate wrench, bar or tensioner tool, rotate the tensioner to reduce belt tension (direction varies by model) and slide the belt off an accessible pulley (usually the easiest accessory). Slowly release the tensioner back.
- Theory: the automatic tensioner maintains spring force to keep constant tension. Rotating it compresses the spring so the belt can be removed safely.

5) Inspect and test pulleys, tensioner and accessories
- Spin idler and accessory pulleys by hand; feel for roughness, play, or binding. Check tensioner pulley for smooth travel and return. If bearings are worn, replace those components now.
- Theory: new belt on worn pulleys will quickly fail. Bearings introduce drag or misalignment that causes heat and rib wear; the tensioner spring/damper wears and can’t maintain correct tension.

6) Replace tensioner/idlers if needed
- Remove and install new tensioner/idler(s) per torque specs. Tighten bolts to manufacturer torque.
- Theory: a properly functioning tensioner provides designed tension and damping of belt oscillations; idlers maintain routing and wrap angle.

7) Fit the new belt following the routing diagram
- Route the belt around pulleys except for the one you will use to slip the belt onto after tension is relieved (common practice: leave the tensioner or an accessible pulley for last). Ensure ribs seat in grooves and belt is not twisted.
- Theory: correct routing maximizes wrap angle over driven pulleys for torque transfer and reduces slip; twisting or misrouted belts wear rapidly.

8) Apply tension and check alignment
- Rotate the tensioner again, seat the belt on the final pulley, and slowly release the tensioner so it applies tension. Visually confirm the belt sits squarely in all pulley grooves; check alignment — pulleys must be co-planar.
- Theory: proper tension prevents slippage but avoids over-tensioning which overloads bearings and the belt. Alignment keeps ribs engaged and prevents edge wear.

9) Double-check and torque fasteners
- Verify all fasteners (tensioner/idler bolts) are torqued to spec. Replace any covers removed. Reconnect battery if disconnected.
- Theory: loose hardware allows eccentric movement, belt misalignment and premature failure.

10) Start engine and observe
- Start and run at idle; check for noises, belt tracking, and that accessories operate (charging, A/C, power steering). Rev briefly to see if belt slips under load. After a short test drive, re-inspect belt tension and routing.
- Theory: dynamic check ensures tensioner responds under engine speed and confirms no transient slip or whistle; re-check after thermal cycling because tension can change slightly once warm.

Notes specific to Toyota Hilux (generalized)
- Hilux uses a serpentine belt on most modern petrol and diesel engines; some older models used separate V-belts. Always match belt type and length to engine code/year.
- Direction to rotate the tensioner varies by engine/tensioner design — if there is an arrow on the tensioner housing follow that; otherwise use service manual guidance.
- Common practice: replace tensioner and idler(s) with the belt if the vehicle has high mileage or if the existing tensioner shows wear.

How the repair fixes specific faults (concise)
- Squeal at startup or during acceleration: usually belt glazing/slip or low tension. New belt + correct tension restores friction and stops squeal.
- Intermittent charging (battery warning): belt slip or rib failure reduces alternator drive. New belt & correct routing restore alternator speed and charging.
- Overheating or coolant loss from water pump not driven: belt wear or breakage reduces pump drive. Replacing the belt and inspecting pump pulley ensures coolant circulation restored.
- Power steering noise or loss: belt slip or broken ribs reduce pump drive. New belt restores hydraulic pressure.
- Excessive wear or rapid failure after replacement: f/worn/misaligned pulleys or bad tensioner; replacing those parts fixes the root cause.

Final practical tips (brief)
- Always compare old belt to new to confirm correct length and rib profile.
- If belt runs off the pulley once, stop and re-check alignment immediately.
- Replace tensioner/idlers proactively on high-mileage vehicles for reliability.

End.
rteeqp73