Burning oil smell through vents is a common problem for many car owners. This is especially true if you drive a high-mileage vehicle or if you have neglected regular maintenance.
In this post, I’ll explain the possible causes and how you can get rid of it:
1. Low Engine Oil Level
The oil level in your engine needs to be between the high and low marks on the dipstick. If it’s too low, your engine will overheat and cause damage to itself. It can also cause a burning oil smell through your car vents.
Most manufacturers recommend changing your engine oil every 3,000 miles or every three months. If you follow that schedule, then you should have no issues with regular maintenance of your vehicle. If you neglect this simple task and don’t pay attention when checking your dipstick before driving off, then there could be serious consequences down the line when something goes wrong with your car.
2. Faulty PCV Valve
If you’re smelling a burning oil smell through the vents of your car, it could be that there is oil leaking into your intake manifold. A PCV valve helps to recycle oil vapors in the crankcase back into the engine and prevents them from being released into the atmosphere.
If this valve has become clogged or otherwise faulty, then it will allow some of these oily fumes to escape into your intake manifold. This causes a burnt-oil smell that can come through vents like those on your car’s dashboard or AC vents when you turn on your vehicle’s AC system.
3. Faulty Oil-filter Housing O-ring
The oil filter housing O-ring is a gasket located in the oil filter housing. It’s made of rubber and forms a seal between the engine block and oil filter housing, keeping oil from leaking out of these locations.
The faulty O-ring might simply be from age or damage, but if you’ve recently changed your car’s oil, it could also be because the new filter was put on incorrectly by a mechanic at an auto shop. If you suspect something like this has happened, inspect your car again and make sure everything is tight before driving again.
4. Worn Piston Rings
Your engine’s pistons are a crucial part of the compression system. They seal the combustion chamber, which helps to compress your air/fuel mixture.
There are many different types of piston rings, but they all have one goal: to prevent oil from getting into your exhaust and polluting it, while also preventing exhaust gases from leaking back into the cylinder while you’re driving.
Worn piston rings can cause a burning oil smell if not taken care of in time.
5. Bad Main/Rod Bearings
Main and rod bearings are the most common cause of engine oil leaks. The main bearings are located on the crankshaft, while the rod bearings support the connecting rods.
The main bearings are responsible for supporting all of the weight of the crankshaft, which rotates around an axis that is perpendicular to its length.
Because it must also withstand constant pressure as it rotates, this means that a lot of wear can be expected from this part over time—and if you notice your car leaking oil at this location, chances are good that you’ll need to replace its main bearing assembly. The same goes for the rod bearings.
6. Oil Leak in The Engine
If you smell burning oil coming from the engine, it could be caused by an oil leak in the engine. An oil leak can drip onto the exhaust manifold, which will cause smoke to come out of your tailpipe.
This is a dangerous situation because it can make your car run poorly or even stop running altogether if you ignore it long enough.
7. Bad Catalytic Converter
It is possible for a catalytic converter to get clogged and start burning, which can cause a burning oil smell through the vents. The catalytic converter is meant to absorb fuel so that it does not go into its harmful form in the environment.
If there is buildup from carbon or other materials, this absorption can become limited and will not work properly anymore. When this happens, the unabsorbed fuel will start to burn and make the car smell like burning oil.
8. Exhaust Leak
If the burning oil smell is stronger when you first start your car and then goes away, this is a sign of an exhaust leak. The exhaust manifold is a common source of the burning oil smell.
When you drive faster, there is more air rushing through the engine compartment, which increases the velocity at which all fumes are circulating around your engine, including those coming from leaks in your exhaust system.
If you have an exhaust leak, it will be worse when you drive faster because there will be more air flowing through it and spreading out into other areas where there may not be enough ventilation.
9. Poorly Done Oil Change
Poorly done oil changes can cause a burning smell. If you’re not getting your oil changed at a professional place, it’s possible that the technician has left some of the old, dirty oil in your vehicle. That dirty old oil can build up over time and potentially cause serious damage to your engine.
It’s also possible that they didn’t put enough new clean oil into your vehicle when they did an “oil change” so there wasn’t enough lubrication during driving. This can cause overheating and other issues that can lead to smelling like burning rubber or something similar.
How to Eliminate the Burning Oil Smell Through Your Car Vents
1. Determine The Cause of The Smell
If you are experiencing a burning oil smell, it’s important to first determine the cause of the problem. The burning smell may be coming from your furnace or air conditioning system. This can be caused by low refrigerant levels in your AC system.
But, if it is not being caused by a lack of refrigerant, then it is likely that there are some other causes of the smell. You have to first ensure that you find the exact cause so that you can fix the problem.
2. Replace The PCV Valve
The best way to fix this issue is by replacing the PCV Valve altogether with an updated version that works better than before. This doesn’t just stop the leaking. It also eliminates the strong odor you perceive.
To do this, you’ll need to remove your car’s valve cover and then disconnect the old PCV valve from its connection point inside your engine. Next, install the new part in its place by screwing it back into place with an adjustable wrench or a ratchet set.
3. Replace Worn Piston Rings
If you have an oil-burning problem, the piston rings may be worn out. Worn piston rings contribute to poor combustion, as they allow more oil to pass through them and into the cylinder.
To check if your piston rings need replacing, remove the spark plugs and look inside each cylinder. If you notice any visible carbon buildup on your spark plugs, it’s likely that the cylinder walls have been damaged by excessive blow-by gases that escape past seals or gaskets before being burned in combustion.
This could indicate that your engine has worn piston rings so check to see if they’re cracked or broken off completely. Replace the worn piston rings to get rid of the problem. Once this task is completed, run another series of tests on your vehicle for about 10 minutes.
4. Repair Bad Catalytic Converter
If you’ve been smelling burning oil through the vents, it’s likely that your catalytic converter is broken. This can cause internal damage to other parts of your car and cause toxic fumes to come out through the vents.
To replace a broken catalytic converter, you’ll need to remove all four wheels from your vehicle so you can access its underside.
Next, locate where the catalytic converter is located on your engine (it may be near or under one of two exhaust pipes), remove any bolts holding it in place and carefully pull off the old unit before installing the new one back into place with new bolts.
5. Repair Exhaust Leak
If you are smelling burning oil through the vents, the likely culprit is an exhaust leak. You can check for leaks by locating your car’s muffler and tailpipe. If you see any cracks or holes in these areas, it will be obvious that a repair job is needed.
If your car has an exhaust leak, try tightening all of its fasteners to prevent further damage from occurring. If this does not solve the problem, consider replacing worn parts with new ones from an auto parts store or mechanic shop if possible.
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It is important to remember that the burning oil smell is not something to ignore. The best thing you can do for yourself and your car is to investigate what may be causing it. In this case, there are many possible causes of an oil leak in the engine.
It could be as simple as a worn piston ring or a loose O-ring on the oil filter housing, a faulty PCV valve, low engine level, bad main or rod bearings, exhaust leak, poorly done oil change, a bad catalytic converter, or oil leak in the engine.
If these problems are left untreated they can lead to larger issues down the road such as bad bearings or even catastrophic failure.
Ugo is a passionate car enthusiast with a Bachelor of Electrical and Electronics Engineering degree and hands-on experience in troubleshooting and fixing automobiles.
I combine my electrical and mechanical engineering knowledge with practical skills to address car-related issues.
My love for cars and dedication to educating others led to the creation of Fixandtroubleshoot.com!