A vehicle losing oil quickly is concerning, especially if it coincides with blue smoke or a burning smell. It can mean your car is burning oil, and it may lead to severe issues with expensive repair costs.
How do you tell if your car is burning oil?
In this article, we’ll explore the signs of a car burning oil, its potential causes, and seriousness. We’ll also cover possible fixes, repair costs, and whether it can lead to a failed emissions test.
This Article Contains:
- What Are the Signs of a Car Burning Oil?
- Why is My Car Burning Oil? 7 Possible Causes
- What Happens if I Ignore Burning Oil?
- What Can I Do About My Car Burning Oil?
- How Much Does it Cost to Fix a Car That’s Burning Oil?
- Will a Car Burning Oil Fail Emission Tests?
Let’s go.
What Are the Signs of a Car Burning Oil?
If your car’s burning oil, you’ll notice signs like:
- Blue smoke from the exhaust: Bluish smoke can indicate your car is burning oil during the combustion cycle.
- Burning oil smell: A thick burning oil smell could mean oil is seeping onto hot engine parts.
- Frequent low oil light warnings: Regular low oil warnings can indicate excessive oil consumption or a car burning oil.
But here’s the thing:
Some newer car models burn motor oil faster than others. BMW cars may burn a quart of motor oil within 1000 miles, while General Motors use less than a quart for 2000 miles.
So, check the expected engine oil consumption for your vehicle model. Moreover, a good practice to identify if your car is burning oil is to have a mechanic check your car’s oil level every 1000 miles.
Generally, an engine under 50,000 miles shouldn’t use more than a quart per 2000 miles. If it uses more, it could be a sign of oil burning. However, engines over 75,000 or 100,000 miles generally have high oil consumption.
Next, let’s explore why a car could be burning oil.
Why is My Car Burning Oil? 7 Possible Causes
Here are potential reasons for a car burning oil:
1. Blocked or Worn Positive Crankcase Ventilation (PCV) Valve
The crankcase contains parts like the oil pan, crankshaft, pistons, and cylinders. These pistons generate combustion gases, which create pressure in the crankcase when the engine operates.
The combustion gases are typically recirculated into the combustion chamber through the PCV valve. They’re burned in the combustion chamber before being released through the exhaust.
But when the PCV valve that lets the gas out is clogged or worn, it can cause oil blowback — where oil, instead of gas, is sucked into the engine through the air intake and burned.
2. Damaged Valve Seal or Guides
Generally, a valve seal helps regulate oil consumption by keeping oil from leaking into the engine cylinders and combustion chamber.
But If it’s damaged, oil can leak past the seal. This leak may worsen if the valve guides are also worn out.
All this leads to oil leaking down the valves and burning. As the valves degrade further, the oil eventually reaches the combustion chamber and releases bluish smoke when burned.
3. Broken or Worn Piston Ring
A piston may have three types of piston rings:
- Compression ring: It allows the piston to compress the air/fuel mixture without any leaks.
- Wiper ring: It is a backup piston ring that stops gas leakage beyond the compression ring. This ring also wipes excessive oil off the cylinder wall.
- Oil control ring: This piston ring wipes and returns excessive oil from the cylinder wall into the oil reservoir.
The wiper ring and oil control ring prevent extra oil from entering the combustion chamber.
But here’s the deal:
A worn piston ring may let oil leak into the internal combustion chamber. This can lead to oil burning, increased oil consumption, and creates carbon deposits on the cylinders and piston rings.
Plus, blow-by gases enter the crankcase while gathering oil vapor. This is then pushed back into the intake tract via the PCV system.
4. Oil in the Turbocharger
Another potential reason for burning oil (in turbocharged vehicles) are leaking turbocharger seals.
Turbochargers use oil to lubricate the turning bearings. But when the seal deteriorates, extra oil can leak past the bearings and seep into either the:
- Compressor or cold side of the turbo leading to the intake
- Exhaust or hot side of the turbo leading to the exhaust
Both of these leaks result in burning oil. Moreover, the bearings will eventually fail, causing total turbo failure.
5. Leaking Head Gasket
A prime location for burning oil is a head gasket leak, which may be due to damage from the continuous heating and cooling of the cylinder head gasket.
Cylinder head gaskets seal oil galleries in the engine block. This allows circulation without an oil or coolant leak. But if the head gasket leaks, it can dump oil directly into the cylinders and engine.
Note: Like the head gasket, the valve cover gasket also helps prevent oil leaks.
6. Oil Filter Cap Leak
The oil filter cap covers the opening through which you fill the engine.
But if the cap is worn out or loose, engine oil can flow onto the surface of the engine and burn.
7. High Oil Pressure
Oil can flood the engine due to high oil pressure (a potential symptom of excess oil or a Powertrain Control Module defect).
And when this oil falls on the cylinders, it burns.
Now, let’s see what happens if you don’t address these issues promptly.
What Happens if I Ignore Burning Oil?
A car burning oil is a moderately serious issue that can do further damage besides decreasing your car’s oil level.
What damage does it cause?
Here are the potential risks of ignoring burning oil:
- Spark plug damage
- Catalytic converter overheating or failure
- Engine damage or failure
So, burning oil or an oil leak must be addressed soon.
Though if it’s an emergency, you could drive for a short distance. But you’ll need to add engine oil frequently, so it doesn’t go below the recommended level.
Let’s explore what you can do to resolve the issue.
What Can I Do About My Car Burning Oil?
Since a car burning oil can lead to engine problems, it’s best to have a professional address the issue.
Here’s what a mechanic would do to fix a car that burns oil:
- A mechanic would first determine the cause of the oil burn.
- They’d do an oil change to replace low-quality or old oil with a high-mileage synthetic oil. This synthetic oil contains additives that help stop leaky piston rings by creating a tight seal.
- The mechanic would replace any leaks or damaged engine parts, like a seal or gasket, that let oil into the combustion chamber or exhaust.
- If the damage is severe, they may have to replace the engine.
But what can you do to prevent the damage from escalating?
The best way to prevent further damage in a car that burns oil is through regular maintenance.
But other measures you could take include:
- Use oil with the correct viscosity for your vehicle, as mentioned in your owner’s manual.
- Avoid aggressive driving or driving that can put a lot of stress on your engine, as it may cause the oil to break down faster. This can lead to your car burning through oil faster, enabling a higher risk of engine damage.
After knowing what needs to be done about an oil burn, let’s explore how much it’ll cost you.
How Much Does it Cost to Fix a Car That’s Burning Oil?
Depending on the auto repair needed, here are estimates for some replacements and fixes with their labor cost:
- PCV replacement: About $100
- Head gasket replacement: Around $900-$1,800 per cylinder head
- Gas Engine: Around $1,000-$5,700 (a diesel engine may cost much more)
The prices above can vary based on the car’s make and how early or late you address the issue. In general, the longer you wait, the greater the damage to your car and wallet.
Plus, if your car burns oil, it may fail certain inspections.
Will a Car Burning Oil Fail Emission Tests?
Yes, it’s possible a car burning oil may fail an emission test.
Why?
If your car burns oil, it could lead to heavy smoke or emissions from your exhaust system.
And that’s not all!
Old or poor-quality oil could also make your car fail an inspection.
Final Thoughts
A car burning oil could happen for several reasons, most of which are hard to discover or fix at home. Plus, the consequences of ignoring the issue can be heavy on your car and wallet.
That’s why it’s best to leave the issue to professional mechanics from a trusted auto repair company like AutoNation Mobile Service.
With AutoNation Mobile Service, you get easy online bookings and high-quality repairs.
Why not reach out today to have an expert mechanic diagnose the issue right from your driveway?