2.0 subaru engine problems

So, you're here because you're curious, worried, or downright frustrated about potential issues with your 2.0 Subaru engine. Maybe you're considering buying one, or perhaps you already own one and you've noticed something a little…off. Don't worry, you're not alone. The 2.0-liter engine, found in popular models like the Impreza, Crosstrek, and some Foresters, is generally reliable, but like any engine, it has its quirks and potential pitfalls. Let's dive deep and uncover what you need to know to keep your Subaru running smoothly.

Is the 2.0 Subaru Engine Really That Bad? Let's Be Honest.

The short answer is no, the 2.0 Subaru engine isn't inherently "bad." It's a generally robust powerplant that offers decent fuel economy and adequate power for everyday driving. However, certain model years and specific engine variants have earned a reputation for certain problems. Understanding these potential issues is crucial for preventative maintenance and informed decision-making. We'll break down the most common gremlins and how to tackle them.

Oil Consumption: The Subaru's Biggest Appetite?

(Oil consumption) is arguably the most talked-about issue with some 2.0 Subaru engines, particularly those from around the 2012-2017 era. It’s not uncommon for owners to find themselves adding oil between scheduled changes, sometimes a significant amount. But why does this happen?

Piston Ring Design: The piston rings are responsible for sealing the combustion chamber, preventing oil from entering and burning. Some 2.0 engines, especially those mentioned above, had piston ring designs that didn't provide optimal sealing. This allowed oil to seep past the rings and get burned along with the fuel.
PCV Valve Issues: The Positive Crankcase Ventilation (PCV) valve helps regulate pressure within the engine. A faulty PCV valve can cause excessive vacuum, which can pull oil into the intake manifold and subsequently into the combustion chamber.
Driving Habits: Aggressive driving, especially frequent high RPMs, can exacerbate oil consumption issues. The higher the engine speed, the more likely oil is to splash and potentially bypass the piston rings.

What can you do about it?

Regular Oil Level Checks: This is the most basic but crucial step. Check your oil level at least weekly, or even more frequently if you suspect an issue.
Use the Correct Oil: Subaru specifies a particular oil viscosity for its engines. Using the correct oil type can help minimize oil consumption. Synthetic oil is generally recommended.
PCV Valve Replacement: A relatively inexpensive and easy fix. If you suspect a faulty PCV valve, replace it.
Oil Catch Can: An oil catch can is a device that filters oil vapor from the PCV system, preventing it from entering the intake manifold. This can help reduce oil consumption over time.
Engine Rebuild (in severe cases): If oil consumption is excessive and other measures fail, an engine rebuild might be necessary to replace the piston rings with an updated design.

The Dreaded Head Gasket: A Subaru Classic?

While not as prevalent on the 2.0 engine as it was on older 2.5-liter engines, (head gasket failure) is still a potential concern. The head gasket seals the cylinder head to the engine block, preventing coolant and oil from mixing. When it fails, it can lead to a variety of problems.

Overheating: A blown head gasket can allow coolant to leak into the cylinders, causing the engine to overheat.
Coolant Loss: You might notice a decrease in coolant levels without any visible leaks.
White Smoke from Exhaust: This indicates that coolant is burning in the cylinders.
Milky Oil: If coolant mixes with the oil, it can create a milky or frothy appearance on the dipstick.

What can you do about it?

Monitor Coolant Levels: Regularly check your coolant levels and top off as needed.
Watch for Overheating: Pay attention to your temperature gauge and pull over immediately if you notice the engine overheating.
Head Gasket Inspection: If you suspect a head gasket issue, have a mechanic perform a compression test or leak-down test to diagnose the problem.
Head Gasket Replacement: Replacing the head gasket is a significant repair, but it's essential to address the issue before it causes further damage. Make sure to use a high-quality gasket and have the cylinder heads resurfaced to ensure a proper seal.

The Ticking Time Bomb: Valve Train Noise

Some 2.0 Subaru engines, especially those with the FB20 engine code, can develop (valve train noise). This often manifests as a ticking or tapping sound, particularly when the engine is cold.

Valve Lash Adjustment: The valve lash is the clearance between the valve stem and the rocker arm or camshaft. Over time, this clearance can become excessive, leading to noise.
Hydraulic Lash Adjusters (HLAs): Some engines use HLAs to automatically maintain the correct valve lash. These HLAs can become clogged or fail, leading to noise.
Worn Camshafts or Rocker Arms: In rare cases, the camshafts or rocker arms can wear down, causing noise.

What can you do about it?

Valve Lash Adjustment: If your engine has adjustable valve lash, have it checked and adjusted according to the manufacturer's specifications.
HLA Replacement: If your engine uses HLAs and they are causing the noise, they can be replaced.
Oil Change: Sometimes, a simple oil change with the correct viscosity oil can help quiet down valve train noise.
Engine Flush: A gentle engine flush can help remove deposits that might be clogging HLAs.

The Annoying Misfire: Ignition System Woes

(Misfires) can occur in any engine, and the 2.0 Subaru is no exception. A misfire happens when one or more cylinders fail to fire properly, leading to rough running, reduced power, and poor fuel economy.

Spark Plugs: Worn or fouled spark plugs are a common cause of misfires.
Ignition Coils: Faulty ignition coils can prevent the spark plugs from firing.
Faulty Wiring: Damaged or corroded wiring to the ignition coils or spark plugs can also cause misfires.
Fuel Injectors: Clogged or faulty fuel injectors can prevent fuel from reaching the cylinders.

What can you do about it?

Spark Plug Replacement: Replace your spark plugs according to the manufacturer's recommended interval.
Ignition Coil Testing: Use a multimeter to test the resistance of the ignition coils. Replace any coils that are out of spec.
Wiring Inspection: Inspect the wiring to the ignition coils and spark plugs for damage or corrosion.
Fuel Injector Cleaning or Replacement: If you suspect a fuel injector issue, have them cleaned or replaced.

The "Check Engine" Light Mystery: Sensor Issues

The ("Check Engine" light) can illuminate for a variety of reasons, and sensor problems are a common culprit.

Oxygen Sensors: Oxygen sensors monitor the amount of oxygen in the exhaust gas and provide feedback to the engine control unit (ECU). Faulty oxygen sensors can affect fuel economy and emissions.
Mass Airflow Sensor (MAF): The MAF sensor measures the amount of air entering the engine. A faulty MAF sensor can cause rough running, poor fuel economy, and a "Check Engine" light.
Crankshaft Position Sensor (CKP): The CKP sensor monitors the position of the crankshaft. A faulty CKP sensor can prevent the engine from starting.
Camshaft Position Sensor (CMP): The CMP sensor monitors the position of the camshaft. A faulty CMP sensor can also prevent the engine from starting or cause rough running.

What can you do about it?

Diagnostic Scan: Use an OBD-II scanner to read the trouble codes stored in the ECU. This will help pinpoint the source of the problem.
Sensor Replacement: Replace any faulty sensors with new ones.
Wiring Inspection: Inspect the wiring to the sensors for damage or corrosion.

Don't Forget the Little Things: Regular Maintenance is Key

Beyond the specific issues mentioned above, regular maintenance is crucial for keeping your 2.0 Subaru engine running smoothly.

Oil Changes: Change your oil and filter according to the manufacturer's recommended interval.
Air Filter Replacement: Replace your air filter regularly to ensure proper airflow to the engine.
Coolant Flush: Flush your coolant system every few years to prevent corrosion and maintain proper cooling.
Spark Plug Replacement: Replace your spark plugs according to the manufacturer's recommended interval.
Timing Belt/Chain Inspection: Inspect the timing belt or chain for wear and tear. Replace it if necessary to prevent catastrophic engine damage. (Note: Some 2.0 engines use a timing chain, which generally lasts longer than a timing belt.)

Frequently Asked Questions

Is the 2.0 Subaru engine reliable? Generally, yes. With proper maintenance, the 2.0 Subaru engine can be reliable, though some model years and engine variants have known issues.
What years of the 2.0 Subaru engine are most prone to oil consumption? The 2012-2017 model years are often cited as having higher rates of oil consumption.
How often should I change the oil in my 2.0 Subaru? Follow the manufacturer's recommendations, but typically every 6,000 miles or 6 months is a good practice, especially with synthetic oil.
What does a "Check Engine" light mean? It indicates a problem detected by the engine control unit (ECU), requiring a diagnostic scan to determine the cause.
Can I fix oil consumption myself? Minor oil consumption might be addressed with a PCV valve replacement or an oil catch can, but severe cases may require professional attention.

Wrapping Things Up

The 2.0 Subaru engine, while generally a solid performer, can experience a few common problems like oil consumption, head gasket issues, and valve train noise. Understanding these potential issues and adhering to a strict maintenance schedule will dramatically improve the lifespan and reliability of your engine. Proactive care is always the best defense!