5 Causes of Burning Oil Smell Through Vents

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burning oil smell through vents

The stench of burning oil smell through vents can be stressful for drivers. In addition to preventing you from driving effectively, this symptom can signify the presence of issues. If your car vents smell burning oil, it doesn’t automatically mean that something is probably really burning your engine oil.

However, the issue is where it originates and what causes it. There are, in fact, several probable reasons, and it’s crucial to determine what’s happening so you can rectify the condition as quickly as possible.

This article will lead you through the most prevalent reasons for a burnt oil smell emanating from your vehicle vents. Because there’s no doubt about it, it’s not normal to smell oil while driving, and if your car emits a burning oil stench, you must locate the source and repair it immediately. Read on to learn more!

Why Your Vents Blow Burning Oil Smell

When engine oil leaks and spills on hot surfaces, like the exhaust manifold or exhaust pipe, it burns and disappears, creating a burning oil stench in your engine compartment. This could facilitate the passage of the odor of burning oil via your car’s HVAC intake at its windshield bottom. Evaporated engine oil disappears with almost no trace, making it more challenging to discover leaks.

Causes Of Burning Oil Smell From AC Vents

No one likes to smell a burning oil from air vents while driving. It’s not only uncomfortable, but it may also make driving hazardous. If your vents emit this odor, it must get examined so that the cause of the odor may be determined and remedied. Below are the reasons for the burning oil smell coming from your vents.

Valve Cover Oil Leak

Oil leaks seeping out of your valve cover gasket are the most typical and potential origin of this problem. Oil leaking on the back end of your valve cover could often result in spilled oil dripping on your exhaust system, causing an odor of burnt engine oil in your engine compartment. Such leaks are challenging to detect since the oil dissipates and leaves no hint.

On the portion where your engine slants by design, oil leaks from your valve cover are prone to gather. Because of the slant, it’s evident that the oil would leak more from the back of most cars with longitudinally placed engines. Accessing the back end of your valve cover might be challenging when diagnosing the engine.

Due to the car’s age, a loosened or broken valve cover nuts or bolt is probably causing the issue. A damaged valve cover gasket could also cause oil to leak out over time. Assume you spotted the leaks in the portion of your valve cover accompanied by broken valve cover bolts. In this instance, it’d be best to replace both your valve cover bolts and gasket to prevent further leaks.

Exhaust Leak

Exhaust leaks within your engine compartment can transmit a burning odor via your AC vents that many drivers can identify as a burnt oil odor. Any crack or hole near your exhaust manifold, pipe, or catalytic converter might let exhaust gasses penetrate your car cabin, causing a nasty, burning smell.

However, it’s not hard to spot exhaust leaks. Similar to detecting a hole in a tire, you could use a spray bottle and scatter soapy water over your exhaust manifold and exhaust pipes while your engine is cold and let it run for a moment.

Watch for the emergence of bubbles in the sprinkled portions to detect leakage. You can also detect exhaust leaks since they alter your engine’s tone if the fracture, gap, or hole is significant. Your engine might produce a whistling or whizzing sound when the exhaust fumes seek another route to escape without passing via your tailpipe.

PCV Valve Leak

PCV valves mounted on your valve covers regulate your engine’s positive crankcase ventilation. A bad PCV valve can trap high pressure within your valve cover, harm your valve cover gasket, and loosen the bolts.

This could lead to oil seeping within your engine compartment, generating a burning smell when dripped onto a heated surface. If a faulty PCV valve is detected, you must check the sealings of your valve cover gasket since a flawed PCV valve can quickly break your gasket and dislodge the bolts.

Leaks or fractures within the vacuum hoses linking your PCV valve can prevent it from operating as designed. You can examine your PCV valves by removing them from your valve cover. If your PCV valve is functioning correctly, you can feel a significant vacuum on the valve as you put your fingertip on it while your engine is operating.

Exhaust System Oil Leak

Leaking motor oil from any location or component due to a crack, hole, or loose component could cause oil to stream on hot engine surfaces. It might also produce an odor of burning oil within your cabin. Indications of oil leaks include oil leaking on the ground and greasy dirt covering the lowest portion of your engine bay.

Oil Change Done Poorly

An improper oil change might result in extra oil spilling into your exhaust system and other components. As your engine warms up, the oil on the hot surface will evaporate, leaving the vehicle with a distinct oil smell. If there’s no other leak, the oil will entirely burn up, and the odor will go within a couple of days.

How To Make Burning Oil Smell Go Away?

Using an air freshener to eliminate the burning oil stench would’ve been convenient, but no air freshener or purifier can provide a lasting cure. Determining the source of the issue, repairing any leaks, and replacing components may offer better outcomes. The following solutions might help you eliminate the burning oil smell from your vents.

Determine The Cause Of The Problem

It isn’t easy to draw a judgment without understanding what is producing the burning scent. It could be a simple engine oil leak that managed to reach your exhaust, or it might be the consequence of severe oil ring or gasket wear.

Various viscosity oils are required for the engine, brakes, and transmission, making it difficult to determine which component is defective without a complete inspection. Even If you raise the vehicle and inspect underneath, you might not discover anything. Therefore it’s advisable to see a professional technician or visit an auto repair shop.

Don’t Overlook The Signs

If you disregard a problem’s signs in its early stages, you might have to contend with a much larger issue in the future. Suppose your vehicle’s gears aren’t shifting correctly, or there’s an undesirable noise during gear changes. In that case, your engine is running hotter than usual, and its oil level is dropping dramatically without any apparent leak.

And the brakes are functioning with a delay, these are essential issues that might not seem like a huge concern to some, but if neglected over an extended period, they’ll become a significant nuisance. Once you begin to smell burning oil, your oil is almost certainly leaking, and it could be too late to fix the leaks quickly.

Because of a lengthy period of neglect, your gear shaft damage got more threatening. The worst is that your pistons and rings have been severely damaged and are incapable of retaining the oils; therefore, you sense the stench of burning oil. It’ll be prudent to pay attention to the little things, as this will assist you in preventing the smell of burning oil from escalating and producing further issues.

Is It Normal To Smell Oil From Vents After Oil Change?

No, it isn’t normal to detect a burning oil smell after an oil change if done correctly and if there are no oil leaks in your car. Burning oil odor quickly after changing your engine oil can often be attributed to the following causes.

Spilled Oil

Oil spilling is a rather evident and common occurrence during a regular oil change. If this oil reaches your exhaust or any other spot that generates high heat, you might detect a burned oil stench surrounding your vehicle. The burning odor might linger for some time, but there’s no need for alarm.

Loose Oil Drain Plug

To change your engine oil, you must unscrew your drain plug and some components to drain the old oil and dirt that accumulated with it. This is to make your engine clean for your new oil. If your oil filter, oil cap, or drain plug isn’t correctly fastened or is loose, the oil will leak, and you’ll smell it burning when it touches any hot engine surface. It’d be best to double-check things after the oil change.


Oil is required to maintain the engine’s functionality, brakes, transmission, and other mechanical parts. A leak occurs if you detect a pungent stench of burned oil coupled with noise or discomfort when driving your vehicle or if your engine heats up erratically. It’d be prudent not to ignore these difficulties and undergo a full assessment.

Other Burning Smells

Below are some other burning smells that may come out of your AC vents to watch out for, and their causes.

Burning Plastic Smell

It’s among the most common problems encountered by drivers. A  burning plastic stench emanating from your AC vent indicates a significant dust accumulation. Most car owners are primarily concerned with the outside gloss and frequently disregard those inside components, such as vents, which must be maintained and cleaned often.

A malfunctioning cooler or heater may also cause the plastic odor emanating from the vent. The heater includes antifreeze substances, and once they leak into your exhaust, a distinct burning plastic stench will occur.

Burning Rubber

Burning rubber produces a distinct odor that’s detectable in any circumstance. Once your vent emits a distinct smell of burnt rubber, it’s necessary to inspect all your automobile belts. There might be a problem with your AC compressor, and these problems may place substantial stress on your rubber belts. Due to excessive stress and heat, your rubber belts could melt or wear out.

Burning Fish

If you detect a foul smell of cooked fish within your automobile, there’s a significant likelihood that the electrical wires in your vehicle have deteriorated or are burning. These electric wires are copper with polymer shielding, so if you smell a combination of burning plastic and cooked fish, you must immediately address the wiring problems.


A strong odor of burning oil emanating from your vents suggests a potential exhaust or oil leak. Stop your vehicle and inspect your engine compartment for indications of oil leaks. Alternately, you can take your car to a technician and have an expert check it.


Does spilled engine oil evaporate?

Indeed, if engine oil spills on a heated surface, it can quickly evaporate, producing a burning oil odor.

Can spilled oil harm my engine?

If an external factor produced the leak, oil spilled on the engine is unlikely to cause harm. But if the oil leak results from engine leakage, you must immediately get the problem checked and corrected.

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