my Toyota Highlander Third Generation (2014-2019) engine rattles when idling what causes this

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.
• Raise the vehicle and secure it on jack stands if underbody access is required.

2. Inspect and Replace Engine Mounts

• Sub-steps:
  • Locate the engine mounts (typically found on the front and rear of the engine).
  • Use a socket set to remove the bolts securing the engine mounts to the frame and engine.
  • Carefully lift the engine slightly using a jack to relieve pressure on the mounts.
  • Replace worn or damaged mounts with new ones, ensuring proper alignment.
  • Torque the bolts to the manufacturer specifications (usually around 40-50 ft-lbs, but confirm with a repair manual).

3. Check Exhaust System

• Sub-steps:
  • Inspect the exhaust system for loose hangers or clamps that could cause rattling.
  • Tighten any loose bolts or replace damaged hangers.
  • Check for any signs of exhaust leaks or damage to the exhaust components that may require replacement.

4. Inspect Serpentine Belt and Tensioner

• Sub-steps:
  • Visually inspect the serpentine belt for cracks, fraying, or signs of wear.
  • Check the tensioner for proper operation; it should have adequate tension on the belt.
  • Replace the belt if it shows any signs of wear and replace the tensioner if it does not maintain proper tension.

5. Inspect Timing Chain/Belt

• Sub-steps:
  • Remove any necessary covers to access the timing chain/belt.
  • Inspect for excessive slack or wear on the chain/belt.
  • If any wear is found, replace the timing chain/belt and associated components (e.g., guides, tensioners) according to manufacturer specifications.