Q: Hissing sound

asked by on August 23, 2016

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).

Check Engine Light is on Inspection $79.99 - $89.99 Get a Quote

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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

What others are asking

I have a 2004 Hyundai Santa Fe with bent valves on both heads. I'm wondering if this is worth fixing?

Hello, thanks for writing in. I will try to help you with this. If the car has no other significant repair needs (i.e., costs), the calculation is fairly straightforward. If other repairs are required it is much more complicated. So,...

Hello, I got a code indicating bad oxygen sensor (bank 2, sensor 1). Where is that located on a 09 Hyundai Genesis sedan 4.6 v8?

For your model, bank 2 of the engine consists of the 4 cylinders in a row on the driver's side of the vehicle. Sensor 1 is the sensor mounted on the manifold ahead of the catalytic converter. Generally, oxygen sensors...

Why does it take a while for the car to crank.

Any time you disconnect a battery all the modules in your car loose their internal memory. When you changed your battery the engine control module was reset and it may take a few weeks for it to relearn your engine...

Knocking noise valve clatter

Hello. It's quite possible, even likely, that the crankshaft bearing journals are worn out of specification. Replacing the rod bearings only does not compensate for a worn crankshaft rod (or main) bearing journal. It's also possible the oil pump pressure/volume...

Which Toyota engine I can use to replace a Hyundai Tucson engine

Hello. I would not recommend having this done as the cost to do this (absent a free motor and labor), will likely exceed the value of the car. You may want to consider selling the Hyundai and purchasing the Toyota...

I have a 2006 dodge charger and there is oil in the water pump what can it be

Oil can leak into the cooling system from the head gasket, through cracks in the head or block and at other points depending on the design of the engine. The coolant will only boil if the radiator pressure cap is...

Car burning oil

Hi there, thanks for writing in about your 2006 BMW 750Li. The two causes of an engine to burn oil are faulty piston rings and faulty valve guides or seals. If the piston rings are faulty, this will allow oil...

Alternator not grounding on 2000 BMW 323Ci

Hello. If this occurred right after the accident, then I would check the ground connections on the battery first. If they are fine, then the wire going from the battery to the alternator needs to have a voltage drop test...

Front right suspension area making a clicking noise that speeds up as car goes faster. My car is a 2013 Infiniti G37x.

Hi there. The clicking noise in the right front may be, any number of possibilities. A loose wheel, a wheel bearing going bad, possible brake pad movement, resulting from poor fitting pads, a worn axle shaft cv joint. There are...

Related articles

The Best Used Cars to Buy If Your Kid's On the Soccer Team
If If you are a soccer mom (or dad), you know that you need a lot of space to transport your budding World Cup contenders, along with their gear. From time to time, you can also expect to be bringing...
A Buyer’s Guide to the 2012 Hyundai Accent
Hyundai Hyundai has become a force to be reckoned with in the automobile industry, as they have been improving many different elements of their vehicles – under the hood and with the exterior styling. The 2012 Hyundai Accent is proof...
Symptoms of a Bad or Failing Driveshaft
Common signs include intense car vibrations and abnormal noises, like clunking, rattling, and scraping, coming from under the vehicle.