2018 Toyota Corolla Has A Vacuum Leak

Diagnosing Vacuum Leaks in Your 2018 Toyota Corolla: Symptoms, Causes, and Repair Solutions

Find Repair Location
Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Leaking Vacuum Hoses
0%
30% chance it's the
Leaking Gaskets and Seals
0%
20% chance it's the
Bad Actuators and Valves
0%
10% chance it's
Something else
The most common reasons a 2018 Toyota Corolla has a vacuum leak are leaking vacuum hoses, leaking gaskets and seals, or bad actuators and valves.
  • Leaking Vacuum Hoses: A cracked or disconnected vacuum hose can lead to a loss of engine vacuum, resulting in poor engine performance and increased fuel consumption.
  • Leaking Gaskets and Seals: Aged or damaged gaskets and seals can lead to fluid leaks, resulting in loss of engine oil or coolant and potential engine damage.
  • Bad Actuators and Valves: A malfunctioning actuator or valve can disrupt the proper operation of the vehicle's systems, leading to issues such as poor engine performance or erratic behavior of components like the HVAC system.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2018 Toyota Corolla has a vacuum leak?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Problems with the intake manifold gasket can create the following symptoms:

  • Illuminated check engine light
  • Erratic engine performance
  • Oil and coolant leaks
  • Poor gas mileage
  • Stalling

» LEARN MORE: Intake manifold gasket symptoms

Rough idling, lack of power, engine oil leaks, engine burning oil, and illumination of the check engine light are all possible if the PCV valve has clogged. If the check engine light comes on, the on-board diagnostics (OBD) trouble codes will most likely relate to manifold vacuum, air and fuel mixture, PCV system, mass airflow sensor readings, and exhaust and emissions readings. These are all affected in the event the PCV valve is clogged, is stuck fully open, or is stuck fully closed, however, if the valve is stuck fully open, the engine oil seals are not in danger of overpressure.

A bad valve cover gasket will result in an oil leak. You may notice oil under the car or on other parts under the hood. You might also notice a burning smell while driving.

» LEARN MORE: Signs of a bad valve cover gasket

Any time there is an emissions fault the check engine light will be displayed. The purpose of the check engine light is to inform the driver that an emission related fault has been found, and that there are on-board diagnostic (OBD) trouble codes stored in the powertrain or engine control module. Additionally, since the emissions systems are so intertwined into engine control and transmission control systems, symptoms may include nearly any sort of drivability concerns. This may include harsh shifting, failure to shift, hesitation on acceleration, jerking, engine failure to start or run, loss of power, or any number of other drivability issues.

What are the steps to diagnose a vacuum leak in a 2018 Toyota Corolla?

To effectively diagnose a vacuum leak in a 2018 Toyota Corolla, begin with a comprehensive visual inspection of the engine compartment. Look for any signs of wear such as damaged hoses, loose connections, or cracked tubing that could be allowing air to escape. Once you've completed the visual check, start the engine and listen for any hissing noises, as these sounds often indicate a leak. If you have a vacuum gauge, connect it to the intake manifold; a reading that is lower than normal can signal a vacuum leak. Another useful technique is to spray soapy water on the vacuum hoses and connections while the engine is running; if bubbles form, this will help you pinpoint the leak's location. For a more thorough investigation, consider performing a smoke test, which involves introducing smoke into the vacuum system to visually identify any escaping air. Finally, if the check engine light is on, using an OBD-II scanner can provide specific trouble codes that may relate to a vacuum leak. By following these steps, you can systematically diagnose and address any vacuum leaks in your Corolla, ensuring optimal engine performance.

What are the common causes of a vacuum leak in a 2018 Toyota Corolla?

Understanding the common causes of a vacuum leak in a 2018 Toyota Corolla is essential for any DIY mechanic looking to maintain their vehicle's performance. One of the primary culprits is damaged or worn-out vacuum hoses, which can deteriorate over time, leading to cracks or looseness that allow air to escape. Additionally, a faulty intake manifold gasket can create a significant vacuum leak, as it is responsible for sealing the manifold to the engine. Another area to inspect is the throttle body; if it is not properly sealed or has sustained damage, it can also contribute to leaks. Furthermore, cracked or damaged vacuum fittings can compromise the system's integrity, while a malfunctioning brake booster can introduce unwanted air into the engine, affecting both performance and braking efficiency. By being aware of these potential issues, DIY enthusiasts can take proactive steps to diagnose and resolve vacuum leaks, ensuring their Corolla runs smoothly and efficiently.

How urgent is it to address a vacuum leak in a 2018 Toyota Corolla?

Addressing a vacuum leak in your 2018 Toyota Corolla is not just a matter of convenience; it is crucial for maintaining the vehicle's performance and safety. A vacuum leak can lead to a range of problems, including rough idling, stalling, and significantly reduced fuel efficiency, which can compromise your driving experience. Moreover, if left unaddressed, a vacuum leak can cause long-term damage to the engine, leading to costly repairs down the line. The urgency to fix this issue cannot be overstated, as timely intervention can prevent further complications and ensure that your vehicle operates smoothly. By prioritizing the repair of a vacuum leak, you not only enhance your car's performance but also safeguard your investment in the long run.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.