How do I stop my engine from burning oil?

The most reliable way to stop oil from burning is to diagnose the underlying cause and fix it, which commonly points to the PCV system, valve seals, or worn piston rings. In many cases, a simple PCV valve replacement or valve-seal service reduces consumption; more extensive wear may require engine repairs or a rebuild.

Why engines burn oil

Oil can burn when it escapes from seals into the combustion chamber or is drawn into the intake or exhaust system. Understanding the typical culprits helps homeowners decide when to seek professional help and what to ask for during a diagnosis.

• Worn piston rings or scored cylinder walls, which allow oil to enter the combustion chamber.


• Worn or leaking valve guides and valve seals that let oil seep into the intake or combustion chamber.


• A faulty or clogged PCV (positive crankcase ventilation) system that creates excessive crankcase pressure or pulls oil into the intake.


• Turbocharger seal failures in turbocharged engines, allowing oil to enter the intake or exhaust.


• Overfilling the oil or using an incorrect viscosity, which can promote burning or oil foaming.


• External oil leaks (valve covers, oil pan, seals) that reduce oil level and can be mistaken for burning.

Technicians usually rule out leaks and PCV problems first, then assess internal wear if consumption continues.

Diagnosis: how to confirm the cause

To identify the root cause, follow a structured diagnostic path and track oil usage over time. A clear oil-consumption history makes it easier to distinguish between leaks and true burning.

1. Observe symptoms: blue smoke from the exhaust and rising oil consumption indicate burning oil; document consumption over a defined period (for example, over 1,000 miles).


2. Inspect the PCV system: test or replace the PCV valve, inspect hoses for leaks or clogs, and clean intake deposits if present.


3. Check for external oil leaks: inspect valve covers, front/rear seals, oil pan, and gaskets; repair leaks to ensure you measure true consumption.


4. Run compression and leak-down tests: determine whether rings or cylinders are worn or scored.


5. Evaluate valve seals/guides: excessive oil burning at idle or low rpm can point to seals or guides needing service.


6. Check turbocharger health (if applicable): inspect turbo oil feeds, seals, and intercooler for oil contamination that could indicate a failed seal.


7. Consult a professional if needed: engine teardown or specialized tests may be required for a definitive diagnosis and repair plan.

These steps help distinguish PCV faults, valve-seat issues, and ring or bore wear, guiding appropriate repairs and setting realistic timelines and costs.

Treatment options: fixes by cause

Once the root cause is identified, these are common repair paths. Some fixes are simple and inexpensive; others involve significant engine work. Start with the least invasive option that addresses the specific fault.

• PCV system service: replace the PCV valve and hoses; clean oil and varnish from the intake manifold and throttle body to restore proper ventilation.


• Valve seals or guides replacement: replacing worn valve seals or guides can dramatically reduce oil burning in many engines, usually without a full engine teardown depending on design.


• Piston rings or cylinder work: worn rings or scored cylinders typically require engine disassembly and possible ring/piston replacement or a full rebuild, with results varying by engine type and mileage.


• Turbocharger seals (if applicable): repair or replace turbo seals and inspect oil feeds; fixing a failed turbo seal can markedly reduce oil consumption in turbocharged engines.


• Oil specification and maintenance: use the manufacturer-recommended oil grade and viscosity, avoid overfilling, and ensure proper oil changes at recommended intervals.


• Address external leaks: replace gaskets, seals, and lines to stop external loss, which helps ensure measurements reflect true internal burning.

Costs and timelines vary widely by vehicle and the chosen approach; obtain a detailed diagnostic and written repair estimate before approving work.

Practical tips to reduce oil consumption now

While planning repairs, these interim actions can help minimize oil loss and protect engine health.

• Maintain proper oil level and follow the manufacturer’s change intervals; use the recommended oil grade for your engine and climate.


• Track oil usage over time to detect accelerating consumption and catch problems early.


• Heed symptoms promptly: blue smoke and rising consumption warrant prompt inspection to prevent catalyst damage and excessive emissions.


• Avoid aggressive driving: high RPM and heavy loads can worsen oil consumption in engines with wear.


• Consult a qualified technician for persistent cases: internal wear typically requires specialized tests and tooling.

These steps keep you running while you plan and finance the appropriate repairs.

Summary

Oil burning is usually a sign of internal engine wear or a ventilation fault, rather than a simple external leak. Start with a PCV and seal check, review oil consumption trends, and pursue repairs aligned with the diagnosed cause. With timely maintenance and targeted fixes, many engines reduce or stop burning oil, extending life and reducing emissions.

Why is my oil disappearing but no leak?

Losing oil with no visible leak is most likely due to the engine burning the oil internally. This can happen when worn components like piston rings or valve seals allow oil to slip into the combustion chamber, where it's burned off. Other causes can include a faulty PCV valve or a blown head gasket. You should have a mechanic inspect your car to prevent severe engine damage. 
This video explains the common causes of an engine burning oil: 59sHonest Mechanic ColoradoYouTube · May 22, 2024
Common causes of internal oil loss

• Worn piston rings: The rings create a seal between the piston and cylinder wall. As they wear down, oil can slip past them and burn in the combustion chamber. 
• Worn valve seals: These seals prevent oil from leaking down the valve stems. If they fail, oil can enter the combustion chamber. 
• Faulty PCV valve: The positive crankcase ventilation (PCV) system removes pressure from the crankcase. If the PCV valve is clogged, it can cause pressure buildup and force oil into other parts of the engine, leading it to be burned. 
• Blown head gasket: A damaged head gasket can allow oil to leak from the engine's oil passages into the combustion chambers. 
• Engine wear: Over time, general engine wear can lead to more oil being consumed during normal operation. 

You can watch this video to see how a faulty PCV valve can lead to oil burning: 1mScotty KilmerYouTube · Oct 7, 2014
What to do next

• Check for blue smoke: While you may not see an external leak, burning oil can often produce a blue or grayish smoke from the exhaust, especially when the engine is under load or after idling. However, if the oil loss is gradual, the smoke might not be noticeable. 
• Consult a mechanic: It is best to have a professional diagnose the problem. They can perform tests like a compression or leak-down test to pinpoint the source of the oil loss. 
• Address the issue promptly: Ignoring oil loss can lead to significant engine damage and costly repairs. Getting the problem fixed early is crucial for your car's longevity. 

How to fix an oil burning engine?

If you find that your car is burning through oil faster than normal, there are a few things you can do to help mitigate the problem.

1. Check for leaks regularly.
2. Use the correct oil grade.
3. Follow the recommended oil change interval.
4. Avoid excessive idling.
5. Drive responsibly.

Can oil consumption be fixed?

Yes, a car that burns oil can often be fixed, but the repair depends on the cause, ranging from simple fixes like replacing a PCV valve or changing oil viscosity to major engine repairs like replacing piston rings or valve seals. For a less expensive, temporary solution, using an oil additive or higher-viscosity oil may help, but a permanent fix often requires professional diagnosis and intervention. 
Simple fixes

• Check for leaks: Look for puddles under the car, as leaks are often cheaper to fix than internal engine problems. 
• Replace the PCV valve: A faulty PCV valve is a common and simple fix for oil burning caused by excessive pressure in the crankcase. 
• Use the correct oil: Ensure you're using the manufacturer's recommended oil viscosity. Thinner oils can sometimes slip past seals and burn more easily. 
• Change oil and filter: A clogged oil filter can cause increased pressure. Changing the oil and filter is a good first step. 

More complex and expensive fixes

• Replace valve seals: Worn valve seals can allow oil to leak into the combustion chamber, causing blue smoke on startup. This can be a moderately expensive repair that doesn't always require a full engine overhaul. 
• Address piston rings and cylinder walls: Worn piston rings or cylinder walls are a more serious issue. This allows oil to enter the combustion chamber, especially during acceleration. A "shotgun" approach, which includes replacing piston rings and valve seals, is sometimes recommended for older cars with high mileage. 
• Fix a bad turbocharger: If your car has a turbocharger, a failed seal can cause it to leak oil into the intake or exhaust, leading to high oil consumption. 
• Engine overhaul: For severe wear, an engine rebuild or replacement may be the only permanent solution. This is a very expensive option that may not be worthwhile depending on the car's age and value. 

Temporary solutions

• Use oil additives: Products like Motor Honey are designed to be added to your engine oil to thicken it and reduce burning. 
• Switch to a thicker oil: A mechanic might suggest switching to a higher-viscosity oil (e.g., from a 5W-20 to a 5W-40) to help reduce oil consumption. 
• Use high-mileage oil: Oils formulated for high-mileage engines contain additives that can help condition and soften old seals, which may slow down oil consumption. 

Important considerations

• Don't ignore the problem: Burning oil can damage the catalytic converter, spark plugs, and other engine components, leading to more costly repairs if left unaddressed.
• Consult a professional: Because of the wide range of potential causes and repairs, it is best to have a qualified mechanic diagnose the issue to determine the right fix for your specific car. 

What can I put in my engine to stop it burning oil?

Treating an oil-burning engine can involve using oil additives to clean deposits, using thicker oil, or performing more involved engine repairs like a piston ring or valve job. Additives can help restore performance by cleaning internal engine parts, while a thicker oil may temporarily reduce consumption. For a lasting solution, particularly in older engines, major repairs may be necessary. 
Short-term or minor treatments
This video demonstrates how to diagnose an oil burning engine: 1mScotty KilmerYouTube · Oct 31, 2023

• Use engine oil additives: Products like Sea Foam, Bardahl, or Lucas Oil are designed to clean carbon deposits, which can restore the ability of piston rings to seal properly. These can be added to the engine oil or fuel. 
• Use a piston soak treatment: A special detergent can be poured into the engine, which is then idled to clean carbon deposits from the pistons and rings. 
• Switch to a thicker oil: Using the heaviest weight of oil recommended for your engine can help reduce oil consumption, though this is not a permanent fix. 

Long-term or major repairs
You can watch this video to learn how to perform a BG service on a car that is burning oil: 52sDeutsche Auto PartsYouTube · May 19, 2022

• Perform a valve job and/or ring job: For significant oil burning, the only way to fix the issue is to rebuild the engine. This may involve replacing the piston rings or performing a valve job.
• Replace the engine: In severe cases, especially in older vehicles, replacing the engine may be more cost-effective than a full rebuild. 

Important considerations

• Consult a professional: It is best to have a mechanic diagnose the cause of the oil burning to determine the appropriate course of action.
• Monitor oil levels: Regardless of the treatment, it is crucial to check your oil level frequently and add oil as needed to prevent engine damage. 
• Understand limitations: Additives may not be a permanent fix and might not work for severely worn engines.