The Mystery Of Burning Oil: Full Pan, Burning Engine

If you're noticing a burning oil smell, it's important to get your car checked out as soon as possible. Burning oil can be caused by a number of issues, from a worn-out oil filter cap to a blocked crankcase ventilation valve, or even just poor oil quality. The most common cause is a leak in the engine, which can be hard to spot. This allows oil to come into contact with hot engine surfaces, causing it to smoke and possibly ignite. Other signs of burning oil include a fast decrease in oil levels, bluish smoke from the exhaust, and a pungent odour.

Clogged crankcase ventilation

A clogged crankcase ventilation system can cause oil leaks, which can lead to burning oil. The crankcase ventilation system is designed to relieve pressure from the engine's crankcase by rerouting blow-by gases (gases that escape from the combustion chamber past the piston rings) back into the engine's intake manifold to be consumed by the engine.

If the crankcase ventilation filter gets dirty or clogged, it can restrict airflow and the system's pressure-relieving capacity. This can cause a build-up of pressure, leading to blown gaskets and seals, resulting in oil leaks. Oil leaks can cause burning oil if the leaking oil comes into contact with hot engine surfaces, such as the exhaust system, where it can smoke and possibly ignite.

To address a clogged crankcase ventilation system, it is recommended to have the vehicle serviced by a professional technician. They can replace the failing crankcase vent filter and perform any necessary services to resolve the issue.

Leaking seals or gaskets

Seals are designed to keep oil inside the engine, but they can wear down over time and allow oil to escape. The most common culprits for seal leaks are the crankshaft and camshaft seals. The constant motion of these components puts a lot of stress on the seals, causing them to wear out and leak.

If you notice oil leaking from your vehicle, it is important to get it checked by a professional technician. Small leaks can turn into major issues if left untreated, leading to expensive repair bills. To prevent oil leaks, regular maintenance is key. This includes oil changes, inspecting for worn gaskets or loose parts, and ensuring the oil filter is installed and tightened correctly.

If you suspect a leaking gasket or seal, a mechanic can diagnose the problem and perform the necessary repairs. Gasket replacements can be complex, and if not done correctly, can lead to further leaks or damage. It is important to address oil leaks in a timely manner to prevent engine damage and ensure the smooth performance of your vehicle.

Poor or wrong oil quality

• Reduced fuel economy: Using too thick an oil for the conditions will increase resistance on moving parts such as pistons, leading to more frequent trips to the gas station.
• Poor cold-temperature starting: If the cold viscosity of the oil is too high, it may be too thick to properly lubricate all moving parts, causing excess resistance during cold starts.
• Engine ticking in cold weather: Using too thin an oil for cold conditions can result in a ticking noise as the metal components hit against each other due to poor lubrication.
• Burning oil smell: If the hot viscosity of the oil is not high enough, it may break down under extreme conditions, leading to a burning oil smell and potential long-term engine damage due to excess friction between metal components.
• Increased sludge buildup and worn seals in the oil pan: Using the incorrect oil can cause issues with the oil pan, such as increased sludge buildup and worn seals, resulting in oil leaks and decreased engine performance.
• Carbon buildup in the engine: Conventional oils with unstable molecule structures can easily burn off when heat is present, leading to accelerated carbon buildup in the engine.

To remedy these issues, it is essential to use the correct type and viscosity of oil recommended by the vehicle manufacturer. Refer to the owner's manual to determine the appropriate oil type and viscosity for your specific vehicle.

Bad piston rings or pistons

Piston rings, often referred to as oil control rings, are small, inexpensive components situated deep within the engine. They are affixed to the pistons and play a crucial role in pressurising the combustion cylinder.

When piston rings deteriorate, they can create a pathway for engine oil to seep into the combustion chamber. This oil then becomes an unintended participant in the combustion process, mixing with the fuel and air. This produces an unusual byproduct: smoke. The colour of this smoke, often blue or grey, indicates that oil is burning within the engine.

The piston rings are the seal between the piston and the cylinder walls, which keep the combustion chamber's pressure and oil in the crankcase. If they deteriorate or fail, your car's engine will start losing power, and hundreds of other problems may arise.

The most common symptoms of bad piston rings are high oil consumption, blue smoke coming from the exhaust pipe during acceleration, and a loss of power in your car.

If the piston rings are bad, you will get high pressure inside the crankcase. This makes the engine seals fail and start leaking oil. If you see many different oil leaks, you should check the pressure in the crankcase.

If your piston rings are bad, it can cause damage to the cylinder walls, which can result in needing to replace the entire engine block.

The cost to replace your piston rings is between $1000 and $5000, depending on the car model and labour costs. The piston rings cost $40 to $200, depending on how many cylinders your car has. The labour work is between $1000 and $4000.

High oil pressure

If you are experiencing high oil pressure, start with the basics. Have you had an oil change recently? If you did, can you verify that the oil used was the right type? Beyond that, high oil pressure is a good indicator of other, more serious issues with your engine. It's a good idea to get things checked out to rule out anything big.

Frequently asked questions