Engine knocking, ticking or losing power? What it means

What the noise usually means

• Light ticking that speeds up with the engine: often low oil or a valvetrain part. Some direct-injection engines also tick normally, so a change in the sound matters more than the sound itself.
• Pinging or rattling when you accelerate or climb a hill: often fuel igniting too early. It can come from carbon buildup, a sensor problem or fuel with a lower octane than the manual calls for.
• A deep knock that gets faster as you rev: can be a worn bearing inside the engine. Stop driving; this one can end an engine.
• Squealing at start-up: usually a belt that is slipping or worn.

Rough idle, shaking or losing power

• Shaking at a light, or a stumble when you accelerate: usually a misfire from a spark plug, ignition coil or injector.
• Hesitation or weak acceleration: can be fuel delivery, a dirty airflow sensor, a clogged air filter or a vacuum leak.
• Sudden loss of power with a warning light: many cars go into a reduced-power mode to protect themselves when they detect a fault.

What the smoke color tells you

• Blue or gray smoke: oil is burning inside the engine.
• Thick white smoke that smells sweet: coolant is burning, which can mean a head gasket problem. Watch the temperature gauge.
• Black smoke: the engine is running rich, burning too much fuel.
• A little thin white vapor on a cold morning that goes away is normal condensation.

Check the oil first

Park on level ground, turn the engine off, wait a few minutes and check the dipstick. If the oil is low, top it up with the grade listed in your owner’s manual and keep an eye on it: an engine that keeps needing oil is either leaking or burning it. Oil that is overdue for a change breaks down and protects less, which is one of the most common reasons engines wear early.

When to stop driving

• The oil pressure light comes on.
• There is a deep knock that follows engine speed.
• The check engine light is flashing.
• The temperature gauge climbs toward hot, or you see steam.
• There is heavy smoke, or you smell burning.

Pull over somewhere safe, turn the engine off and call. A few more miles can turn a repair into a replacement.

How we handle it here

• We listen to it, drive it, check the oil and read the codes and live engine data, then test the suspected part before recommending anything.
• We do engine repair in our shop. We tell you what we found, what is urgent and what can wait, and give you the price before any work starts.
• Nothing is done without your approval, and you can ask for a written estimate.
• We are open 24 hours a day, 7 days a week, and we speak English and Spanish.