my Toyota Corolla E170 (2013-2019) is making a hissing noise when I start it, what's wrong

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Vacuum Hoses

1. Identify Vacuum Hoses: Locate all vacuum hoses connected to the intake manifold.
2. Visual Inspection: Check hoses for any signs of wear, such as cracks or brittleness.
3. Test for Leaks: Apply a small amount of soapy water to suspect areas; bubbles will indicate leaks.
4. Replace Damaged Hoses: Use new vacuum hoses of the correct diameter and length, replacing any damaged hoses.
5. Reconnect: Ensure all hoses are securely connected.

3. Examine and Replace Intake Manifold Gasket

1. Remove Intake Manifold: Disconnect any cables or sensors attached to the manifold. Remove bolts securing the manifold and lift it off.
2. Inspect Gasket: Examine the intake manifold gasket for signs of damage or wear.
3. Clean Surface: Use a scraper to gently clean the mating surfaces on the engine and the manifold.
4. Install New Gasket: Place a new intake manifold gasket in position.
5. Reinstall Intake Manifold: Carefully place the manifold back and secure it with bolts to the specified torque value (typically around 15-22 lb-ft, but check manufacturer's specifications).
6. Reconnect Cables/Sensors: Ensure all disconnected components are reattached properly.

4. Clean Throttle Body

1. Access Throttle Body: Remove the air intake duct connected to the throttle body.
2. Clean Throttle Body: Use throttle body cleaner and a soft cloth to remove carbon deposits inside the throttle body.
3. Reassemble: Reconnect the air intake duct securely.