Car Engine Oil Cooler Guide

Oil coolers are generally small radiators that are situated in front of an engine’s cooling system in an automobile. Its aim is to cool the oil as it passes through the coils and it only operates when the engine is running.


Oil coolers are mainly responsible for cooling an automobile’s oil. This extends the life of both the oil and the car’s engine.

How it Works

Automobile engines produce a tremendous amount of heat and therefore depend on transmission fluid for cooling. The ideal temperature range for engine oil is 180 degrees to 200 degrees. While working within this range, the oil functions as a lubricant, coolant and cleanser for the engine.

As oil cycles through the tube and fin style coolers, heat is drawn out from the oil to the external fins where it is dispelled through air flow.

Aftermarket Coolers

In most cases, oil coolers are installed by the owner of the vehicle, as most transmissions are designed to be fitted with oil coolers.

Vehicles that Benefit Most from Oil Coolers

Vehicles that benefit the most from oil coolers are ones that do any kind of towing or are used in a hot climate. In many cases, oil coolers are added to trucks, motor homes as well as to other types of heavy vehicles.

Advantages and Disadvantages

Overall, adding an oil cooler to a vehicle’s engine will extend the life of the oil, therefore extending the life of the engine. However, adding an oil cooler will generate the need of more oil per oil change as there is more oil needed to fill the coil and lines.

Symptoms of a Bad or Failing Oil Cooler

The oil cooler on any production vehicle is an important engine component designed to keep modern cars, trucks, and SUVs running smoothly on the roads they travel daily. Whether you have a 2016 BMW or an older one, yet reliable 1996 Nissan Sentra, the fact remains that the cooling system on any vehicle must be in working order during all weather and driving conditions. Although most drivers never interact with their oil coolers, keeping them in working order will extend their lifespan. However, like any other mechanical component, they can and usually will wear out.

The aim of the engine oil cooler is to allow the engine’s cooling system to remove excess heat from the oil. These types of coolers are mostly of the water-to-oil type of heat exchanger. In most vehicles on the road, engine oil is fed to the oil coolers from an adapter that is found between the engine block and the engine oil filter. The oil then flows within the tubes of the cooler while the engine coolant flows around the tubes. The heat from the oil is transferred by the walls of the tubes to the surrounding coolant similar in many ways to the operation of an indoor air conditioning for residential homes. The heat absorbed by the engine’s cooling system is then transferred to the air when it passes through the vehicle’s radiator, which is placed in front of the engine behind the grille of the vehicle.

If the vehicle is serviced as per the requirement, including routine oil and filter changes, the oil cooler should last as long as the vehicle’s engine or other major mechanical components. However, there might be some occasions where staying on top of maintenance will not prevent all damage potential for an oil cooler. When this part begins to wear out or has broken, it will display a few warning signs. Noted below are a few of these symptoms that can alert a driver that their oil cooler might need to be replaced.

1. Oil leaking from oil cooler

One of the parts that are part of the oil cooling system is the oil cooler adapter. The adapter connects oil lines to the cooler itself and another adapter helps to send “cooled” oil back into the oil pan. The adapter consists of a gasket or rubber O-ring. If the oil cooler adapter fails externally, engine oil might be forced out of the engine. If the leak is small, you might notice a puddle of engine oil on the ground underneath your vehicle or quite possibly a stream of oil on the ground behind your vehicle.

If you notice any oil leaking under your engine, it’s always recommended to contact a professional mechanic as soon as possible so they can determine where the leak is coming from and repair it quickly. As oil leaks, the engine loses ability of lubricating itself. This could result in increased engine temperature as well as premature parts wear due to increased friction from the lack of proper lubrication.

2. Engine coolant leaking from oil cooler

Similar to a loss of oil, an external oil cooler failure might force all of the engine coolant out of the engine. Whether the coolant leak is large or small, you will eventually overheat the engine if it isn’t repaired as soon as possible. If the leak is small, you might notice coolant puddling on the ground underneath your vehicle. If the leak is a large one, you will probably find steam pouring out from under the hood of your vehicle. As with the above symptom, it’s necessary to contact a professional mechanic as soon as you notice a coolant leak. If ample amount coolant leaks from the radiator or oil cooler, it can result in engine overheating problems and mechanical component failure.

3. Oil in the cooling system

If the oil cooler adapter fails internally, you might notice engine oil in your cooling system. This takes place because when the engine is running, oil pressure is greater than cooling system pressure. Oil is forced into the cooling system. This will eventually lead to a lack of lubrication and can severely damage your engine.

4. Coolant in the oil

When the engine is not running and the cooling system is pressurized, coolant can be easily forced from the cooling system into the oil pan. High oil pan levels can damage the engine through the crankshaft slapping the oil as it rotates.

How to Install Engine Oil Coolers

Your car’s engine oil cooler acts like a radiator of sorts for the oil system in the car, keeping the oil at the optimum temperature for the car. Oil that is not cooled properly can lead to a permanent damage to the engine. As the car’s engine runs, the heat that is generated burns the motor oil and can lead to sludge and other residue to build up within the engine and on the pistons which causes the performance problems for the engine. While the engine’s oil filter reduces such a sludge build-up, installing an engine oil cooler can greatly improve the performance and life of your engine. This is particularly true for engines in high-performance vehicles, which can easily burn more motor oil at even higher temperatures, increasing the risk for oil-related engine damage.

Step One — Double-Check Your Parts

Before starting the installation of your engine oil cooler, be sure that you have all necessary parts and accessories for the oil cooler kit and all of the required tools. The job should not begin without having everything needed, including a new filter and fresh motor oil.

Step Two — Drain Your Engine’s Oil

When are you are ready to begin, just remove the existing oil filter from the engine and drain the oil pan of all of its oil.

Step Three — Locate and Remove the Existing Oil Cooler

If you are replacing an existing oil cooler, you might notice it in front of the car’s main radiator, towards the front of the car, just behind the grill. Using your socket wrench, unbolt the old oil cooler from the inside of a car’s frame.

Step Four — Prepare the Frame for Its First Oil Cooler

If you are installing an oil cooler in a car that does not have one, you will have to drill the appropriate mounting holes into the body of the engine block, in front of the main radiator. If you are buying an aftermarket oil cooler, your kit is going to consist of brackets and other accessories to help in mounting the cooler to the body of the car.

Step Five — Mount the New Cooler

Attach the new cooler to the body of the car with your socket wrench to securely tighten the bolts.

Then run the proper oil lines from the engine towards the oil cooler, and from the cooler back to the oil filter. Ensure you have the proper length of oil tubing, and mount the tubing in place where appropriate so it is not loose in the engine block.

Step Six — Replace the Oil Filter and Motor Oil

Install a new oil filter and after that, proceed to fill the oil tank with the appropriate amount of motor oil.

Step Seven — Check the Engine Oil

Start up the car and let it run for a few minutes to allow the engine to warm the fresh motor oil. Then, you need to check the oil level of the car again, as the addition of the oil cooler may require additional oil to reach the “full” level.

Video of How to Install an Engine Oil Cooler

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