Identifying Bad Smells on a Car

Does your car smell like rubber burning or rotten eggs? A car that is running fine should not emit strange smells. If you smell something unpleasant, don’t ignore that strange smell. This guide will help you identify car problems based on the smell.

One way to diagnose car problems is by identifying that strange smell. A bad smell is often the first sign that something is wrong with your car. It is important to identify those odors before they become serious car problems. Let’s examine some of the most common car smells and possible causes.

Rotten eggs smell

A vehicle emitting a rotten egg smell signifies a bad or plugged catalytic converter. The catalytic converter is responsible for converting harmful gases into friendly gases emitted into the air.

When the catalytic converter works inefficiently, the hydrogen sulfide present in gasoline is usually converted to sulfide dioxide, which is odorless. Replacing the catalytic converter costs $250-$400 for an aftermarket universal cat or $700-$1500 if you decide to install an original catalytic converter at the dealer.

In addition, a faulty fuel pressure regulator can also contribute to a rotten egg smell.

Fuel / Gas

A car smelling like gas is extremely dangerous. That means there is a possible fuel leak somewhere in the fuel system. The fuel system is enclosed, and neither fuel nor fuel vapor can escape, however, if this fuel smell is present. I suggest checking the fuel system as soon as possible.

Check the following:
•    Fuel line going from the fuel pump to the engine
•    Check fuel injector seals for possible leaks
•    Check all fuel vapor related to emission
•    Check all fuel lines and hoses at the fuel tank
•    Check the fuel tank for possible damage and leakage
•    Check the fuel pressure regulator hose

Burning Oil Smell

There is a difference between a car smelling like oil and a car burning oil. In this discussion, we will discuss car smells like burning oil. A car smelling like burning oil indicates external engine oil leaking.

Here are the possible areas that should be checked for leaks.

•    Bad valve cover gasket can leak onto the engine and exhaust
•    Bad oil pan gasket can leak onto the exhaust system
•    Bad camshaft and crankshaft seal
•    Leaky rear main seal

Vinegar Smell in the Cabin

If a car smells like vinegar, it is a sign of mold in the air duct. This is due to condensed water left behind when the used air conditioner is. Moreover, the dirty cabin air filter can also contribute to a vinegar-like smell. To reduce condensed water from building up, turn off the air conditioner five minutes before turning the vehicle off. Also, replacing the cabin air filter may help with disinfectant spray.

Excessive Smoke Smell

A car that smells like smoke is a sign of a leaky exhaust system or possibly a severely worn engine.

Check the following:

•    Leaky exhaust manifold gasket
•    Worn piston rings and low compression (use compression gauge)
•    Leaky exhaust fumes somewhere in the exhaust downpipe
•    Rusted muffler
•    Leaks between the catalytic and resonator

Something is Burning

A car is made up of many components. One of the components commonly used is plastic. Plastic can be used anywhere from the interior to the vehicle’s exterior.

If your vehicle smells burning, here is what you should check.

•    Check between the wheel well and the tires. The wheel well can rub against the tires.
•    Check for loose engine undercover that may be touching the exhaust system
•    Check the exhaust system for possible melted plastic  shopping bags that may have got caught in the exhaust
•    Check for engine cover that may come loose and burn on the engine
•    Check for possible loose engine plastic components on the engine bay area that may come loose
•    Check for possible tools  on the engine bay that may have accidentally been left behind by mechanics or technicians

The smell after an oil change

There are a few possible reasons why a car may smell after an oil change. During an engine oil change, the mechanic or lube tech needs to drain the oil and remove the oil filter. In this process, the engine oil can flow from the oil filter housing or drain plug to different areas of the vehicle, usually to the lowest point, sometimes flowing to the exhaust system. The residue/oil then gets burned off by the exhaust.

The wired smell from air vents

The air vents can emit a few strange odors.

Here are some of the odors that can be emitted:
•    Foul smell: a foul smell can be a sign of a dirty cabin air filter that has not been replaced
•    Mold smell: a mold smell is water residue left behind after the air conditioning has been run for a while
•    Dirt smell: It is possible that if you drive on an unpaved road, dirt can enter the air vents, therefore emitting a dirt smell

Bad Clutch Smell

The smell from a clutch system is a sign that the clutch is wearing out. Usually, it smells somewhat like burned metal rubbing against each other. If the vehicle smells like a burned clutch, it is time to replace it.

Here are some of the following symptoms that may display:

•    Unable or difficulty shifting gears
•    RPM jumps when shifting gears
•    Burning metal smell
•    Grinding noise when shifting

The car smells like antifreeze outside.

One of the most common coolants smells from a leaky heater core, cracked radiator, or damaged coolant hose. The upper radiator hose, thermostat housing, lower radiator hose, heater core hoses, broken radiator, and broken coolant reservoir can all contribute to the coolant smell when these components leak.

We hope you find the Identifying Bad Smells on a Car guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.