Subaru is a well-known car brand that has been around since 1953. However, there is one common issue that some Subaru owners may face – burning oil.
In this article, we will dive deeper into the issue of Subaru burning oil and provide you with useful information to help you better understand the situation.
Whether you’re planning to buy a new Subaru or already own one, this article will be a helpful guide for you.
So, let’s get started!
Why is my Subaru burning so much oil?
There are a few potential reasons why your Subaru might be burning oil. One possible cause is worn out piston rings, which can allow oil to leak into the combustion chamber and burn along with fuel.
Another reason could be damaged valve stem seals, which can also lead to oil entering the combustion chamber and getting burned. Here is the possible cause of Subaru burning so much oil.
- Worn out piston rings
- Damaged valve stem seals
- Faulty PCV valve
- Clogged oil passages
- Low quality or incorrect oil used
Worn out piston rings
Over time, the piston rings in your engine can wear out and lose their ability to seal properly. This can allow oil to enter the combustion chamber and get burned along with fuel.
Piston rings are located on the outer diameter of the pistons inside your engine. They act as a seal between the piston and cylinder wall, preventing oil from leaking into the combustion chamber.
Reasons: Worn out piston rings can be caused by a variety of factors, including prolonged use, high mileage, and low oil levels.
However, it’s important to note that piston rings do wear out naturally over time and will eventually need to be replaced.
Symptom/sign: One of the most common symptoms of worn out piston rings causing Subaru burning oil is excessive exhaust smoke.
If you notice thick, blue or gray smoke coming from your exhaust pipe, it could be a sign that oil is being burned in the combustion chamber.
You may also experience a decrease in engine performance and fuel efficiency, as well as low oil levels due to frequent oil consumption.
How to Self-inspect: If you suspect that worn out piston rings may be causing your Subaru to burn oil, there are a few things you can do before bringing it to a technician.
First, check your oil level and see if it has been significantly depleted since the last time you checked.
You can also inspect your exhaust pipe for excessive smoke or residue buildup.
If these signs are present, it’s best to have a professional mechanic take a look at your engine to confirm the issue and make necessary repairs.
Error code: In some cases, vehicles with worn out piston rings may trigger an error code on the car’s onboard diagnostic system (OBD-II).
The specific code will vary depending on the make and model of your vehicle, but it may indicate issues such as misfires or oxygen sensor malfunctions.
Basic Troubleshooting: If you are experiencing Subaru burning oil due to worn out piston rings, there are a few basic troubleshooting steps you can take.
First, check for any leaks or loose parts in your engine that may be contributing to the issue.
You can also try changing your oil and using a thicker viscosity grade to reduce oil consumption.
However, these methods may only provide temporary solutions and it’s important to address the root cause of the problem through professional repairs.
Solutions: Depending on the severity of your Subaru burning oil issue, there are a few potential solutions that may be recommended by a technician.
For minor cases, simply replacing the worn out piston rings can solve the problem.
However, if the issue is more severe and has caused damage to other engine components, a full engine rebuild or replacement may be necessary.
In either case, it’s important to address the issue promptly to prevent further damage and costly repairs in the future.
Costs: The cost of addressing a Subaru burning oil issue can vary depending on the extent of the damage and the solution recommended by a technician.
Replacing worn out piston rings can range from $500 to $1500, while a full engine rebuild or replacement can cost upwards of $3000.
Damaged valve stem seals
Another common cause of Subaru burning oil is damaged valve stem seals.
Valve stem seals are small, circular components that fit over the valves of your engine
These seals prevent oil from leaking into the combustion chamber and when they become worn or damaged, oil can seep through and burn during the combustion process.
Reasons: The most common reason for damaged valve stem seals is high mileage.
As your vehicle ages, the seals can become brittle and fail over time.
Additionally, using poor quality oil or not changing your oil regularly can also contribute to premature wear and damage of these seals.
Another potential reason for damaged valve stem seals is overheating of the engine. This could be caused by a variety of factors such as a malfunctioning cooling system or continuous driving in hot weather conditions.
Overheating can cause the rubber in the seals to deteriorate faster, leading to leaks and eventually a Subaru burning oil issue.
Symptom/sign: If your Subaru is experiencing issues with its valve stem seals, you may notice excessive smoke coming from the exhaust, particularly when starting your car or driving at high speeds.
You may also notice a decrease in engine performance and an increase in oil consumption. If left unaddressed, this can lead to further damage to your engine and potentially costly repairs.
Self-inspect: If you suspect that your valve stem seals may be damaged, here are some steps you can take to self-inspect before bringing your Subaru to a technician:
- Start your engine and let it idle for a few minutes.
- Watch the tailpipe for excessive smoke – if there is an excessive amount of white or blueish-grey smoke, this could indicate burning oil.
- Check your engine oil level using the dipstick – if it is significantly low, this could also be a sign of damaged valve stem seals.
- Look for any visible leaks or drips under your vehicle.
- Listen for any unusual noises coming from the engine while idling or driving.
Error code: Another way to determine if your Subaru is experiencing issues with its valve stem seals is by using an OBD-II scanner.
This device can read error codes from your vehicle’s computer system and may indicate a problem with the valve stem seals.
The specific code related to damaged valve stem seals is P0300, which represents a misfire in one or more cylinders caused by oil leaking into the combustion chamber.
Basic troubleshooting: If your Subaru is showing signs of burning oil and you suspect it may be due to damaged valve stem seals, there are a few things you can try before bringing it to a technician:
- Replace the spark plugs: Worn or fouled spark plugs can contribute to oil leaking into the combustion chamber. Replacing them may help improve engine performance and reduce oil consumption.
- Change the PCV valve: The Positive Crankcase Ventilation (PCV) valve plays an important role in regulating crankcase pressure and preventing excess oil from being drawn into the engine. A faulty PCV valve could contribute to burning oil.
- Use a thicker viscosity oil: In some cases, using a thicker viscosity oil can help reduce the amount of oil that is burning in the combustion chamber. Consult your owner’s manual or a trusted mechanic for recommendations on the best type of oil to use for your Subaru.
- Regularly check and top off oil levels: Keeping an eye on your Subaru’s oil levels and topping off as needed can help prevent excessive burning of oil due to low levels.
Solutions: If basic troubleshooting does not solve the issue, it may be necessary to have your Subaru’s valve stem seals replaced.
This is a task that should be done by a trained technician, as it involves removing and replacing several engine components.
Costs: The cost of replacing damaged valve stem seals can vary depending on the severity of the issue and your Subaru model. On average, this repair can cost anywhere from $500 to $1500.
However, delaying the repair could lead to more serious engine damage and even higher costs in the future.
Faulty PCV valve
As mentioned earlier, a faulty PCV valve can contribute to oil leaking into the combustion chamber and burning oil.
The Positive Crankcase Ventilation (PCV) valve is an important component in regulating crankcase pressure and preventing excess oil from being drawn into the engine.
It is typically located near the engine’s valve cover, and acts as a one-way valve that allows air to flow from the crankcase back into the intake manifold.
This helps to remove harmful gases and vapors from the crankcase while also maintaining proper pressure levels.
Reasons: A faulty PCV valve can be caused by several factors, such as debris or sludge build-up, worn seals, or a clogged breather hose.
It may also be due to wear and tear over time, especially in older Subaru models.
Symptoms/signs: Some common signs that your PCV valve may malfunction include excessive oil consumption, poor engine performance, and the presence of blue or white smoke in the exhaust.
You may also notice an increase in oil leaks or a strong smell of burning oil.
Self-inspect: Before taking your Subaru to a technician, you can perform a simple inspection on your own.
Start by checking the condition of the PCV valve and its hoses for any visible signs of damage or clogs. You can also remove the valve and shake it to see if it rattles freely, indicating that it is still functioning properly.
Error code: If your Subaru’s onboard diagnostic system detects an issue with the PCV valve or its components, it may trigger a check engine light and store a corresponding error code.
Some common codes include P0171 (System Too Lean Bank 1) and P0174 (System Too Lean Bank 2), which can be caused by a malfunctioning PCV valve.
Basic troubleshooting: Depending on the severity of the issue, there are some basic steps that you can take to potentially solve the problem without having to visit a technician.
Start by checking and replacing any damaged hoses connected to the PCV valve. You can also try cleaning or replacing the valve itself if it is clogged or malfunctioning.
Solutions: If the issue persists after performing basic troubleshooting, it is best to take your Subaru to a certified technician for further diagnosis and repair.
They may suggest replacing the entire PCV system or just the valve itself, depending on the extent of the damage. It is important to address this issue promptly as a malfunctioning PCV valve can lead to more serious engine problems in the long run.
Costs: The cost of repairing or replacing a faulty PCV valve can vary depending on the make and model of your Subaru, as well as the extent of the damage.
On average, it can range from $200 to $500 for parts and labor, but this may be more or less depending on your specific situation. It is always best to consult with a certified technician for an accurate estimate.
Clogged oil passages
In addition to a faulty PCV valve, Subaru vehicles may also experience clogged oil passages. This can lead to excessive oil consumption and burning, resulting in the need for frequent oil top-ups.
Clogged oil passages refer to an obstruction or buildup of debris, sludge, or other contaminants within the channels that allow oil to flow through the engine.
In most cases, these passages can be found near the valve cover gasket, camshaft bearings, and crankcase ventilation system.
However, their exact location may vary depending on the specific model of your Subaru. It is important to regularly check and clean these passages to prevent excessive oil consumption and burning.
Reasons: One possible reason is that you regularly change your oil and maintain proper levels, ensuring that the engine is properly lubricated.
Additionally, some newer models of Subarus have been reported to have improved PCV valves, reducing the likelihood of oil burning.
Finally, driving habits can also play a role – frequent short trips or aggressive driving can increase the chances of oil burning due to higher engine temperatures and increased wear and tear on components.
Symptoms/signs: If your Subaru is burning excessive amounts of oil, it may be a symptom of clogged oil passages.
You may also notice decreased engine performance, rough idling, and unusual engine noises.
In some cases, this can lead to reduced fuel efficiency and potential damage to the engine if left unaddressed.
Self-inspect: To check for any potential issues with clogged oil passages, start by visually inspecting the engine and surrounding components for any signs of oil leaks or buildup.
Next, remove the oil filler cap and inspect the inside of the cap for any sludge or debris.
You can also use a dipstick to check the level and consistency of your oil – if it appears thick and dark, it may be an indication of clogged passages.
Lastly, pay attention to any unusual smells coming from your exhaust while driving, as this can also be a sign of burning oil.
Error codes: Common error codes related to clogged oil passages include
- P02A4 (Oil Pressure Too Low)
- P0521 (Engine Oil Pressure Sensor/Switch Circuit Range/Performance)
- P06DD (Engine Oil Pressure Control Circuit)
Basic troubleshooting: In some cases, a simple oil change or using an engine flush product can help dissolve and remove any buildup in the oil passages.
However, if these methods do not solve the issue, it is best to seek professional assistance from a technician who specializes in Subaru vehicles.
They will have the necessary tools and expertise to diagnose and resolve any clogged oil passage issues effectively.
Solutions: Depending on the severity of the clog, the technician may recommend a few different solutions. In some cases, they may simply clean out the passages using specialized tools or chemicals. Other times, they may need to replace certain components such as the oil pump or filter.
Additionally, regular oil changes can also help prevent clogs from occurring in the first place.
Costs: The cost of fixing clogged oil passages on a Subaru can vary depending on the severity of the issue and the specific solution recommended by the technician.
In general, cleaning out the passages or replacing components such as the oil pump or filter can range from a few hundred to several thousand dollars.
However, it is important to address this issue promptly to avoid more expensive repairs in the future.
Low quality or incorrect oil used
Another potential cause of oil consumption in Subaru vehicles is the use of low quality or incorrect oil. As mentioned earlier, Subaru engines require a specific type of high-quality oil to function properly. Using the wrong type or lower grade oil can lead to increased friction and wear on engine components, resulting in higher levels of oil consumption.
FAQs
How can I tell if my Subaru is burning oil?
There are a few signs that may indicate your Subaru is burning oil, such as:
- Blue smoke coming from the exhaust pipe
- Low engine oil levels between oil changes
- Smell of burning oil while driving
If you notice any of these signs, it’s important to have your Subaru checked by a mechanic to determine the cause and prevent further damage to your engine.
Can I still drive my Subaru if it’s burning oil?
In general, it is not recommended to continue driving a vehicle that is burning excessive amounts of oil. Not only can this be damaging to your engine, but it could also potentially lead to safety hazards on the road. It’s best to address the issue as soon as possible and have it repaired by a professional.
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Source
https://www.torquenews.com/1084/subaru-engines-models-and-years-burn-oil-problem-fixed
https://www.subarupartsplus.com/blog/about-subaru-oil-consumption
https://www.mechanicsdirect.com/fixing-your-subarus-high-oil-consumption/