Every time I accelerate my 2009 Ford Ranger XLT there is an annoying whistle sound. I need some advice on where the sound could be coming from. – Anis
That’s not much to go on, but here are my thoughts. As opposed to a clunking noise, which would likely be suspension related, a whistle usually indicates an air leak. Since it occurs while accelerating, this would lead me to believe that you have an issue somewhere in the intake manifold or corresponding air-intake ducting system.
An intake leak will allow unwelcome, unmetered air into the engine. If your check-engine malfunction light is also on, does the powertrain control module (PCM) have a P0171 or P074 code stored? This indicates the PCM has detected an incorrect fuel-to-air ratio because of the air leak, supporting this theory.
Additionally, check the exhaust system, as not all exhaust leaks result in the typical noisy rumble. While your mechanic is under the truck checking the exhaust, have them pay particular attention to the catalytic converter. A partially plugged converter will lead to excessive backpressure and may cause a small upstream exhaust-gasket failure.
Along with that, be aware that whistling sounds can sometimes be confused with high pitched scraping noises. Use this tip to differentiate between the two: Scraping noises, such as from a wheel for example, will increase with road speed, but air/exhaust leaks change with engine speed.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail firstname.lastname@example.org, placing “Lou’s Garage” in the subject line.