Skip the auto shop - Our mechanics make house calls

Q: I have a 2007 mercury mariner. When up to speed it seems fine. When you go from park to reverse or drive there is a whinny noise a

asked by on

When driving the car seems fine but when you come up to a stop it starts to make a whiny noise like a belt issue but the engine a revs up and if you're not on the parking break hard it seems like the car is going to take off on you. In park it's fine but when you put into gear either reverse or drive it revs up high and the noise starts.

My car has 141000 miles.
My car has an automatic transmission.

What you are describing sounds like a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about 750-800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. The whining noise may indicate an alternator that may be failing. When the alternator is not working properly, this may result in the battery quickly losing charge and the car losing all power. You may also notice a whining sound as a result of the bearings inside the alternator begin to fail. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

Was this answer helpful?

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
  1. Home
  2. Questions
  3. I have a 2007 mercury mariner. When up to speed it seems fine. When you go from park to reverse or drive there is a whinny noise a

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: Disconnected battery to install new radio. Reconnected and now it won't start.

Hello, thank you for writing in. Start with the simplest of tests, as all of the symptoms you are having point to an issue with the battery being discharged or incorrectly installed. Make sure the battery is fully charged, and...

Q: I have a 2006 Ford fusion..I recharged the a/c and when I got back in the car I have no interior lights, power windows will not ro

If there is no power to a circuit or circuits that you have commanded on, the diagnostic procedure is to trace the circuit using the factory wiring diagram. That is the only procedure guaranteed to find the fault. A certified...

Q: air conditioning doesn't work. I've put on a new compressor and orifice tube. the computer says something about a evaporator core

I would need a little more information on the actual problem. Is the compressor not coming on? It may have a cycling switch not turning on the compressor. For this problem, the system will need to be tested with gauges,...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...