4 Things That Can Cause A Subaru BOXER® Engine To Overheat

July 15, 2019

Every Subaru vehicle is powered by a BOXER® engine, featuring a unique horizontally opposed design. These engines are smoother and more efficient than many ordinary engines with inline or V-shape configurations -- but, when it comes to overheating, BOXER® engines are just like all modern car engines. They need to be cooled down by a liquid cooling system to prevent overheating. Without this system working properly, the metal components of your engine could get so hot that they actually warp and deform until the engine completely seizes up.

On this page, we've created a list of four things that can commonly cause a car engine to overheat. If your Subaru vehicle starts to overheat, pull over as soon as you can to let the heat die down! Then, consider getting a tow to our service center so we can carry out a repair before your engine suffers anymore overheating damage.

4. Low Coolant Level

Coolant is a special liquid with anti-freezing and anti-corrosive additives that flows through your car's engine, absorbing heat from the engine's hottest parts. That coolant will need to be replaced periodically, as it gathers debris and breaks down over time. You could also lose coolant due to a leak.

When the engine is cool, you can peer under the radiator cap and see how much coolant is in the system. The coolant should pretty much fill the radiator when you check it. If the coolant level is lower than that, you may have a leak that needs to be fixed. It could be leaking onto the ground, which you might notice as a brightly-colored, sweet-smelling puddle under your car. Or, it could be leaking internally, where the engine will burn up the coolant. That can cause a wispy, white smoke to come from your car's tailpipe as you drive. Without the right amount of coolant in the cooling system, your engine is very likely to overheat.

3. Blocked Radiator

Once the coolant has absorbed heat from the engine, it must dissipate that heat somehow. That takes place at the radiator, a system of thin, metal fins through which the coolant flows. The radiator is typically located right behind the front grille so that air will pass over it as you drive. As air flows across the radiator, its increased surface area allows heat to be exchanged from the liquid coolant inside to the outside air. Then, once the coolant temperature has been reduced, it'll flow back toward the engine to repeat the process.

If the radiator has become blocked by debris, there won't be enough airflow across the radiator to keep the coolant at a safe temperature. Furthermore, radiators can corrode and rust over time. That can cause them not to exchange heat as well as they should. You may need a replacement radiator ... or it might be as simple as removing a plastic bag that got sucked into your car's grille.

 

2. Stuck Thermostat

Engine overheating isn't good for your car, but car engines run their best at a warm operating temperatures. A warm engine helps your car's heater warm up your car faster, and helps the engine run as smoothly and efficiently as possible. That's why your car's cooling system has a part called a thermostat. When you first start your car, the thermostat stays closed, preventing coolant from flowing through the system as the engine warms up. Then, once the engine reaches the ideal operating temperature, the thermostat opens up so coolant flows and the engine stays at that temp.

Over time, the spring-loaded thermostat can go bad and get stuck in the closed position. This can cause your engine to overheat, but take heart! As long as there isn't more severe damage inside that's been caused by excess heat, replacing a bad thermostat is a fast, easy and relatively inexpensive repair.