How to Troubleshoot Engine Problems by Sound

A lot can be learned by listening to your engine, so if your car starts to change its tune, you should take heed. As long as you've been paying attention, nobody knows how your engine sounds better than you do, so if it starts to sound odd or even just a little different, there could be a problem. Catching problems early on can help you avoid time at the repair shop later, not to mention the impact on your wallet.

For example, a hissing sound from under the hood could indicate a number of possible problems. You should do a proper investigation of the hissing sound before you dive into any repairs. A hasty solution may turn out to be more costly than it had to be.

Here are some other engine sound issues to be investigated:

Whirring or Whining Sounds

The Symptom: Whirring from the engine that gets worse as engine speed increases, or any noise that increases or decreases with engine rpm.

Possible Cause: Low power steering fluid.
The Fix: Check and fill power steering fluid.

Possible Cause: Bad alternator bearings.
The Fix: Replace alternator.

Possible Cause: A bad water pump.
The Fix: Replace water pump.

Possible Cause: A bad power steering pump.
The Fix: Replace power steering pump.

Possible Cause: A bad air conditioning compressor.
The Fix: Replace air conditioning compressor. (This is not a DIY job.)

Exhaust Sounds

The Symptom: A loud exhaust noise that may be coming from the front or the rear of the vehicle.

Possible Cause: Worn out muffler or exhaust pipe.
The Fix: Replace muffler and/or pipes as required.

Possible Cause: Cracked or broken exhaust manifold.
The Fix: Replace exhaust manifold.

Engine Backfiring

The Symptom: Engine backfires when you press on the gas pedal. When you step on the gas the engine pops, spits, and backfires. Sometimes it's loud, sometimes it's not so loud. This can cause severe engine damage and/or fire under the hood.

Possible Cause: Camshaft timing belt or chain has slipped.
The Fix: Replace timing belt or chain.

Possible Cause: Ignition timing needs adjusting.
The Fix: Adjust ignition timing.

Possible Cause: Spark plug wires on the wrong spark plugs.
The Fix: Check firing order and place wires on the correct spark plugs.

Popping/Stuttering Sounds

The Symptom: Engine hesitates, and a popping sound comes from the engine. When you step on the gas, the engine bogs down or takes a second to respond. You may notice a general lack of power. The problem may occur when the engine is hot or cold or when you are low on fuel. The popping noise tells you something isn't right.

Possible Cause: Dirty air filter.
The Fix: Replace air filter.

Possible Cause: Bad ignition wires.
The Fix: Replace ignition wires.

Possible Cause: Some other type of ignition problem.
The Fix: Check distributor cap or rotor. Ignition module may be bad.

Possible Cause: Internal engine problem.
The Fix: Check compression to determine engine condition.