Burning smell from the engine or vents

What this usually means

A burning smell is a warning you can’t ignore, and the kind of smell points to the source. An acrid, oily smell often means oil dripping onto a hot exhaust. A sharp, hot-metal or chemical smell after braking means overheated brakes or a dragging caliper. A burning-plastic or electrical smell can mean wiring overheating — the most urgent of the group. A sweet smell usually means leaking coolant. Identifying the smell and when it appears is the fastest path to the cause.

Most likely causes

• high
  Oil leaking onto hot exhaustA common cause of an oily, acrid smell — a valve-cover or other gasket leak drips onto the manifold and burns off.
• high
  Overheated or dragging brakesA hot, sharp smell after braking, especially downhill, can mean a stuck caliper or riding the brakes.
• medium
  Electrical / wiring overheatingA burning-plastic smell can mean an overloaded circuit or chafed wiring — treat this as urgent.
• medium
  Leaking coolantA sweet smell, sometimes with steam, means coolant is escaping onto hot parts.
• low
  Slipping clutch or beltA hot, rubbery smell can come from a slipping drive belt or (on a manual) a worn clutch.

How urgent is it?

Typical fix & cost

The repair depends entirely on the source: sealing an oil leak, servicing a stuck caliper, fixing the wiring fault, or repairing a coolant leak. Because one of these (electrical) is a genuine safety risk, confirming the source quickly matters more than usual here.

Related OBD-II codes

If your car has stored a trouble code, these often come with this symptom:

Related symptoms

General guidance, not a substitute for a hands-on inspection. Cost ranges are broad reference ranges, not quotes. For safety-related issues, have the car inspected before driving.