Unless you're attending a barbecue, a burning smell is usually not good. This is especially true for your vehicle because it could mean costly repair bills or a breakdown in the middle of nowhere.
However, the burning smells that may be seeping into the cabin (where the seats are located) area of your vehicle can often be identified both by their distinct odors and accompanying symptoms of trouble.
You can then determine if the issue is minor or if you need to visit your local auto repair shop:
Burning oil produces a strong acrid smell, and in sufficient quantities produces a thick black smoke. You may smell oil burning for various reasons, and a quick check under your hood may reveal the source of the troublesome oil.
You should first look for oil around the fill cap on top of the engine. If you or someone else didn't use a funnel the last time oil was added, or the cap was not tightened securely or correctly, oil may have run down onto the engine and is being burnt away whenever the engine gets hot.
If oil is seen on other sections of the engine, there could be a leak in either the head or valve cover gasket, both of which require extensive labor to remove and replace. However, it should be done as soon as possible to minimize the chances of engine damage from depleted oil.
Burning engine coolant
Engine coolant will technically evaporate instead of burn, and will actually produce a sweet smell. This will be an odor that is familiar from closed parking garages, but with much less intensity in your vehicle.
Your vehicle will actually expel coolant from an overflow tank when it expands from being heated and the volume increases to an amount that surpasses the size of the overflow tank.
However, you shouldn't be able to smell this from inside your vehicle, so a quick inspection is needed to try to ascertain the source of the smell.
You should begin by checking the radiator hoses for any signs of dampness or dripping, as well as for cracks or bubbles that might produce leaks.
You must also check the metal hose clamps that secure the hoses. Loose clamps are a major source of leaks. Tighten the clamps if dampness is found at the clamp locations.
If no apparent leaks are found, check the fluid level on the side of the overflow tank. Fill it with the manufacturer's recommended coolant as needed, then check the level periodically. If you continue to smell coolant or begin to see steam, you may have a thermostat issue that could cause overheating.
Drop by your local auto repair shop to get the thermostat checked, or you may be sitting in a cloud of steam on a hot highway waiting for a tow truck in the near future.