1. Gather Tools and Parts:
- Replacement timing belt
- Timing belt tensioner
- Water pump (optional, but often recommended to replace with the timing belt)
- Coolant
- Socket wrench set
- Torque wrench
- Pliers
- Screwdriver
- Timing light (optional)
2. Prepare the Vehicle:
- Park the 4Runner on level ground and engage the parking brake.
- Disconnect the negative terminal of the battery to avoid electrical accidents.
- Remove the engine's plastic cover and air intake components to access the timing belt.
3. Remove the Timing Belt:
- Locate the timing belt cover, usually around the front of the engine.
- Remove the bolts that hold the timing belt cover in place and remove the cover.
- Use a 17mm wrench to loosen the tensioner pulley.
- Remove the old timing belt by sliding it off the pulleys.
4. Replace the Water Pump (optional):
- If replacing the water pump, now is the time to do so. Remove the old pump and replace it with a new one.
5. Install the New Timing Belt:
- Align the timing marks on the camshaft and crankshaft pulleys with the marks on the timing belt.
- Install the timing belt by slipping it onto the pulleys, starting from the crankshaft and moving clockwise.
- Make sure the timing marks align properly as you install the belt.
6. Tension the Timing Belt:
- Use a torque wrench to tighten the tensioner pulley to the specified torque (refer to your vehicle's manual for the exact value).
- Reinstall the timing belt cover and its bolts.
7. Refill the Coolant:
- If you disconnected any coolant lines during the process, refill the coolant reservoir.
8. Reconnect the Battery and Start the Engine:
- Reconnect the negative battery terminal.
- Attempt to start the engine. If it starts and runs smoothly, the timing belt has been replaced correctly.
9. Verify Timing:
- If you have access to a timing light, you can verify the timing by connecting the timing light to the engine's diagnostic connector and aligning the marks on the crankshaft pulley and timing cover.
Remember, this is a general guide and the exact steps may vary depending on your specific model and engine configuration. It's always recommended to consult a repair manual or seek professional help if you're unsure about any step.
