Q: Q: Hissing sound

asked by on

Hello, on my two cars Hyundai i10 2010 and BMW x3 2006 I can hear a hissing sound when I open the throttle On the Hyundai it can be heard on low rpms and it sounds like a vanos valve(which I doubt that car has) but on the X3 it is much higher and can be heard at high RPMs (Full throttle).

This is normal. What you are hearing is the rush of air entering past the throttle body. You normally don’t hear this because there is much less air passing the throttle plate at lower throttle angles. The sound of the vanos valve is a mechanical noise created by the mesh of gears where the sound you have described here is the sound of air rushing into the motor.

If both vehicles are running well without a Check Engine Light, then this is normal. This noise can be present with a vacuum leak, but a vacuum leak will be apparent under all RPM ranges. If your air cleaner box isn’t secured closed, you will be able to hear this sound much louder and under a wider range of RPM’s. If your were to remove the air filter box, you would hear this sound much more regularly.

The short answer is, this is normal. If your not sure, have one of our technicians take a look at your vehicles. It won’t take much more than opening the hood for an experienced technician to know for sure.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Q: Hissing sound

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Engine oill dropping

There are several reasons for an engine oil level to read low between oil changes. It is common for an engine to consume a given amount of oil, and all manufacturers have a tolerance for what they consider normal consumption....

Q: Car struggles to go into the reverse gear and makes a clunking noise

Other consumers report the type of issue you have with various years and models of BMW but the reports are model specific. If you do a Google search ("difficulty getting reverse BMW "model, year") for your car, you can try...

Q: Hearing clicking from wheel housing while turning

Hi. A clicking noise while turning in a front wheel drive car is usually caused by damaged or worn CV joints. CV joints are mounted on each end of a front axle and they transfer power to the wheels from...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...