why does my Volkswagen Golf MK7 (2015-2019) make a hissing noise when idling

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Vacuum Hoses

• Tools Required: Pliers, new vacuum hoses, hose clamps.
• Check all vacuum hoses connected to the intake manifold for cracks or breaks.
• If damaged, remove the old hoses using pliers and replace them with new hoses, ensuring they are securely fastened with hose clamps.

3. Examine the Intake Manifold

• Tools Required: Socket set, torque wrench, gasket scraper, new intake manifold gasket.
• Remove the intake manifold by unscrewing the bolts using a socket set.
• Inspect the manifold and the gasket for any signs of wear or damage.
• Clean the mating surfaces with a gasket scraper and install a new gasket.
• Reattach the intake manifold and torque the bolts to the manufacturer’s specifications.

4. Check and Replace PCV Valve

• Tools Required: Pliers, new PCV valve.
• Locate the PCV valve, usually found on the valve cover or intake manifold.
• Remove the old PCV valve by disconnecting any hoses and pulling it out.
• Install the new PCV valve, ensuring it fits snugly and reattach any hoses.

5. Inspect Exhaust System

• Tools Required: Visual inspection, possibly a wrench set.
• Visually inspect the exhaust system for any signs of leaks or loose connections, particularly at joints and welds.
• Tighten any loose connections or replace damaged sections of the exhaust as necessary.