Boxer engine differs from the in-line and V-line engines because it is rectangular shaped and adjusted horizontally in your Subaru Outback. These are beneficial because of smoother efficiency and less noise from the engine compartment. It increases the vehicle’s stability because of its low center of gravity. However, these have several problems because of their different performance, location, and size.
Subaru Outback Boxer engine problems include less efficient heat dissipation, high oil consumption, stalling issues, high fuel consumption, faulty ECM, cracked positive crankcase ventilation valve, broken head gaskets, and difficulty in charging the spark plug.
These engines have a complex design, and I had to maintain them frequently for smooth functioning. I sold my SUV to upgrade it to the latest version. I did not face any serious issues in their engines because of the routine maintenance.
| Problems | Solutions |
| Less efficient heat dissipation | Check coolant levels |
| High oil consumption | Use oil with thicker viscosity |
| Stalling issue | Replace fuel pump |
| High fuel consumption | Keep air filters clean |
| Faulty ECM | Subaru updated ECM software |
| High maintenance | Call an expert for maintenance |
| Cracked positive crankcase ventilation valve | Replacement of cracked positive crankcase ventilation valve |
| Broken head gaskets | Replace head gaskets |
| Difficulty in changing spark plug | Keep spark plugs clean to minimize issues |
Less efficient heat dissipation
Engines generate heat because of the overheating of their components. In addition, their parts overheat because of the burning of air and gasoline in the combustion chamber.
Heat dissipation from this compartment is necessary to reduce the risk of cracking and breaking of rubber components. In addition, high temperature also affects the functioning of sensors and various electrical systems.
My friend loves to drive and keep different SUVs. Moreover, he owns vehicles of other brands to tow trailers and campers for road trips. He told me he compared the heat dissipation of the Toyota vehicle containing a V-line engine and the Subaru Outback, which has a boxer type.
I towed the same trailers with both vehicles and checked the temperature of the engine compartment. Subaru SUV engines become extremely hot because of their less efficient heat dissipation system.
These are present horizontally on the ground surface and do not have free space to dissipate heat generated during ignition.
By checking the coolant levels, you can decrease their overheating chances and ensure optimal performance. Inspect the coolant leakages and clogs in hoses to reduce overheating chances. It is also better to check the radiator for proper airflow.
High oil consumption
Many people who own the Subaru Outback complain that their engine with boxer configuration consumes more oil than the V-line.
Oil consumption increases because of their design, which allows the oil to seep through the piston. It burns more oil because of its increased risk of leaking in the cylinder head.
Oil sits on the walls of the cylinder head and can easily move into the combustion chamber for its burning. However, high oil consumption decreases the overall motor oil and increases the chances of engine damage.
It also increases the overheating issue because of the increased friction between the metal parts. Moreover, wear and tear chances also increase because of less friction.
You can minimize oil consumption by changing the motor oil frequently. It is necessary to use the oil, which has a slightly thicker viscosity, to decrease its seeping into the cylinder head. Check motor oil levels frequently through the dipstick method.
Stalling issue
One of my friends also owned the Subaru Outback 2019, and he faced an engine stalling issue while driving on the road.
He checked the batteries of his SUV, but these had sufficient voltage. A few years back, he realized that the fuel pump in his vehicle was not working fine.
A failed fuel pump does not supply sufficient fuel to the combustion chamber for ignition. Subaru did not recall their faulty vehicles at that time. He spent hundreds of dollars on fuel pump replacement.
Subaru recalled their vehicles with the faulty fuel pump in 2020, and they provided the free-of-cost replacement of the component.
Fuel pumps supply sufficient fuel to the combustion chamber for ignition. They fail to perform their functioning because of bad relays, electric connections, corrosion, and debris buildup.
You can contact Subaru dealers if your fuel pump is bad for its free-of-cost replacement.
High fuel consumption
Boxer engines are less fuel-efficient because of their design and configuration. They consume more fuel because these are designed to provide a smoother ride.
The main motive of their horizontal configuration is to ensure the smooth functioning of engine parts.
This configuration is less fuel-efficient because it directs power from the engine to the transmission parts to ensure smooth driving conditions.
You can improve the fuel efficiency by keeping the air filters clean. These are less efficient but provide a smooth, comfortable driving experience for drivers and passengers.
Faulty ECM
The engine control module is a small device or sensor that controls various engine and exhaust system functions. Many people complain that the ECM in their SUVs become faulty and do not monitor the ignition functions correctly.
Continuous ignition and burning of its coil because of the faulty computerized system leads to increased emissions of harmful gasses and overheating.
High temperatures can also cause fuses to blow out, short circuits, and sudden power loss. The issue is common in vehicles that were launched in 2019. Subaru recalled their affected Outback and updated the ECM software for its normal functioning.
High maintenance
The Boxer engine in the Subaru Outback requires high maintenance compared to the conventional V-line engines. It requires high maintenance because of its mounting close to the ground surface.
Moreover, it is better to do regular maintenance instead of becoming worried about costly repairs. In addition, these are costly to maintain because of their different structure.
It is challenging to maintain because of its flat mounting location. It is better to call the expert mechanic for its maintenance instead of doing complicated procedures at home and ending up with messy situations.
Cracked positive crankcase ventilation valve
Crankcase ventilation valves play an essential role in enhancing engine efficiency. It is helpful to remove harmful gases from the combustion chamber.
Sometimes, these PCV valves become bad and get stuck in the open or closed position. The issue worsens when these get stuck in a closed position and do not allow the removal of harmful emissions from the engines.
These become bad because of the sludge, dust, and corrosion build up on their surface. In addition, these are also vulnerable to cracking, which allows the oil to mix with the combustion chamber ignition mixture.
My friend also faced the issue, and he saw gray smoke from the tailpipe, which is not normal. He checked the Subaru Outback Boxer engine parts and saw the debris deposits on the ventilation valve.
He told me he preferred to replace it instead of cleaning it to increase its working efficiency. However, Subaru dealerships also recalled their affected vehicles and replaced the faulty crankcase ventilation valve with a new one.
Broken head gaskets
Boxer engine head gaskets are also vulnerable to wear and tear, which can lead to oil and coolant leakage between the chamber.
Head gaskets can break because of their incorrect size, high engine temperature, and incorrect installation. In addition, corrosion of metal gaskets increases their breaking chances.
Remove the broken head gasket and replace it with a new one of the same size and material to decrease the chances of oil and coolant leakage directly affecting the engine temperature.
Difficulty in changing spark plug
Replacing the worn-out spark plug in the Subaru Outback with a boxer engine is challenging because of its different configuration and location. You cannot access the engine sides to access the faulty or damaged spark plug for its replacement.
It does not have enough space on its sides to access the internal components. The spark plug provides the spark for the air and fuel mixture burning. You can face the issue of loss of power because of a damaged spark and cannot start your engine.
Difficulty in accessing these parts also leads to costly repairs. It becomes bad because of insufficient power supply, blown-out fuse, and carbon buildup.
You can maximize its life and decrease the chances of replacement by maintaining it properly. Use a wire brush or spray cleaner to remove the carbon residues and rust from their surface.
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