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Why is My Car Burning Oil?

It’s common knowledge that oil is a necessity in vehicles. It provides crucial lubrication and cooling to the complex components within your engine. So when you notice the level of your oil motor oil decreasing, it’s no doubt a worrying sight.

In many cases, this is the result of a leak that will accumulate in a puddle or somewhere within the engine bay. However, it’s not always that obvious.

Sometimes there won’t be visible oil leaking outside the engine but you’ll still be losing significant amounts. These circumstances generally point toward the leaking oil being burned off somewhere in or around the engine before forming a noticeable puddle. 

Why is Burning Oil Bad?

While some gradual oil loss is to be expected over long periods, rapid oil loss from an oil-burning issue can lead to expensive or irreparable damage to your engine and transmission through overheating.

Engine oil has some big responsibilities, chief among them being lubrication and temperature control. Oil is essential for the lubrication of the various metal moving parts within your engine, mitigating the friction of metal-on-metal contact. Without this lubrication, the friction will produce significant heat and cause the engine to overheat. Not only this, but an overheating motor will transfer that heat to the transmission as well causing that to build up excessive heat as well. 

As your engine and transmission heat up, they’ll cause warping or cracking to critical metal components like the engine block or head. This of course leads to significant problems, such as a leaking head gasket or loose piston rings. 

Where is My Oil Leaking?

If you’re experiencing a high rate of oil loss and notice the distinct smell of burning oil, there’s almost no doubt you have a leak somewhere within your oil system. Just because you can’t see it accumulated in a puddle or around the engine bay doesn’t mean that you aren’t losing significant amounts of oil, it’s probably just been burned off. 

Two types of leaks lead to burning oil, internal and external leaks.

Internal Oil Leak

Internal leaks refer to any passage that allows oil into the engine’s combustion chamber, causing it to be immediately burned off in the combustion process.

While both internal and external leaks can lead to some serious issues, internal leaks tend to be more pressing as they can not only deprive your engine of oil but disrupt the combustion process as well. 

External Oil Leak

Alternatively, external leaks are exactly what they sound like, oil leaking towards the outside of the engine. The oil exiting the engine externally often makes contact with a scorching hot engine component almost immediately, or drips onto one later, burning it off and leaving you without a visual indicator of the leak’s location. 

What’s Making My Car Burn Oil?

Faulty Valve Seals

Valve seals regulate oil consumption and lubricate the sensitive engine valve stems, creating a seal that stops oil from seeping into the combustion chamber.

However, these seals can allow oil to enter the combustion chamber when they wear over time. The oil will combine with your air/fuel mixture and be burned off during the combustion process, causing both loss of oil and flooded cylinders. 

An engine burning oil within its combustion chambers may first experience carbon and oil build-up coating the electrodes of the spark plugs, leading to misfires that can damage your engine’s internals. Internal oil burn like this is also often accompanied by black sooty smoke emanating from your tailpipe, as the products of burnt oil travel down your exhaust.

If left untreated, this issue will eventually evolve into total engine failure. 

Worn Piston Rings

Similar to the valve seals, piston rings play a huge role in keeping oil from entering the combustion chamber and maintaining proper engine compression. 

The results will be the same too, as oil seeps into the engine and is subsequently burned off, depriving you of crucial oil and disrupting the combustion cycle. This too can lead to irreparable engine damage. 

Piston ring on a piston
Beatrice Murch, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons

Bad Valve Cover Gasket

Your valve cover gasket creates a seal between the engine and the valve cover, preventing your oil from escaping. However, just like any gasket, this seal may wear out over time and eventually fail.

Rather than oil entering your engine like an internal leak from a piston ring, valve cover gasket leaks allow the oil to seep outside the engine. While this sometimes accumulates in noticeable puddles or builds up in the engine bay, it may also drip onto hot engine components and instantly vaporize, consuming that oil before you even realize it. 

Improperly Installed Oil Filter

The entirety of the oil supply in your vehicle passes through a single oil filter to remove harmful contaminants before they enter the oil loop. If this filter has been improperly installed or not sufficiently tightened down, it may cause the oil to leak through the gap and onto the hot engine block or components below. 

Oil filter installed in engine bay
Dvortygirl, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Oil Services & Diagnostics in Peoria

Whether you’re experiencing increased oil consumption or it’s just time for an oil change, look no further than the ASE Certified technicians at Beachlers Vehicle Care & Repair in Peoria, IL. Our team has extensive experience servicing most makes and models, and will ensure your vehicle’s oil system is properly protecting your engine! 

Give us a call or schedule online to chat with our friendly service advisors today!