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).

A: This is normal. What you are hearing is the...

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.

Need advice from certified mechanic? Get help now!

Over 1000 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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: trouble getting into reverse - 2010 Hyundai i20

Hey there. This is a common problem when the transmission synchros are going bad. These are small forks in your transmission that help get your car in and out of gear. When these get worn or break, you will experience...

Q: If I replace the ignition switch, can I use my existing BMW Keys with remote and valet key?

Yes, you can. The ignition switch is separate from the EWS system, so replacing the switch will still allow you to use the current keys you already have. Only if you have to replace a faulty key or EWS module...

Q: engine cranks will not fire, why?

My best guess would be the crankshaft position sensor. I have seen this part fail before without setting a code. It is located on the left side of the engine block, (front of car). It is near the exhaust manifold...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.