Whistling is definitely an unusual noise for any car to make - and an annoying one, too! - but most of the possible causes are easy to diagnose and fairly cheap to fix. In this guide, we’ll cover all the different reasons your car might be whistling and what you can do to fix it.
Dirty Fuel Injectors
This might be surprising, but clogged fuel injectors can actually cause a whistling noise. Typically, the sound won’t be as loud or strong as most of the other causes in this guide, but there will be a number of other symptoms accompanying it. For example, the air-to-fuel ratio will be messed up and the check engine light will come on.
Take your car to a mechanic who will be able to clean or replace your fuel injectors.
Worn Serpentine Belt
The serpentine belt is a continuous belt that is used to drive multiple devices in your car’s engine, including the alternator and water pump. If the belt comes into contact with water, be it from driving through a puddle or from an interior fluid leak, it can start to make a whistling noise. The same applies if the belt becomes loose or damaged.
You can perform a visual check yourself to see if the belt looks like it might need replacing or tightening.
If the whistling sound in your car is most noticeable when you accelerate, the likely culprit is a vacuum leak. The system that controls the air flow between the mass air flow sensor and the engine pushes air through a hose. If the hose comes loose or is damaged it results in a whistling sound as air escapes.
A vacuum leak will make your car run less efficiently and will only get worse with time, so although the repair might not seem urgent, it’s best to get it done sooner rather than later to avoid further damage.
Worn Window Seals
If the whistling is coming from your windows and gets worse when you accelerate, this is probably due to worn out window seals. Constant exposure to heat and cold can speed up the deterioration of the sealant. Fortunately, it’s cheap and quick to replace it yourself.
Faulty Radiator Pressure Cap
A lot of drivers aren’t aware that the radiator pressure cap can actually make a whistling noise if it is damaged or comes loose. This part of your car serves an important purpose in removing excess heat from the coolant.
Take your car to a garage to get the problem fixed so your coolant system can continue to function properly.