Oil Cooler Benefits

Oil Cooler | Highway & Heavy Parts

The oil cooler is not typically a component that goes bad, but should be replaced after any catastrophic engine failure. The best way to protect a new engine investment is to put in a new engine oil cooler to prevent any contamination. On startup, the new engine with higher oil pressure will dislodge trapped debris in the oil cooler and force it into the bearings of the new engine. This can cause premature wear or sometimes an immediate failure. If you're interested in other problems that could lead to failure or the need for a rebuild, read our blog, Signs Your Engine May Need a Rebuild.

The primary job of the oil cooler is to cool the engine lubricating oil, which travels through the main oil rifle, allowing this cooled oil to not only lubricate but cool down a number of other components such as the crankshaft, bearings, camshaft, rods, and pistons.This cooling can impact overall performance. It helps keep the engine running smoothly, during hot weather gear changes or on long-haul trips, for example, when things sometimes have a tendency to overheat and break down.

Oil coolers don't bypass. So if an engine has had bearing, camshaft, or oil pump failure, the oil cooler must be replaced because it can't be flushed. Failure to replace it can lead to repeat failure of a rebuilt engine, too. That's just throwing money away.

Rob McDowell, Sales Technical Support at HHP, shares: “Engine oil is cooled by the cooler allowing consistent oil temperature. In many cases, the bottom of the piston is cooled by a piston cooling nozzle spraying oil to the bottom side of the piston, which helps to regulate piston temperature, and doing so improves efficiency.”

High temperatures are the enemy of any oil system. Keeping it cool, though, is a proven way to extend the life of your engine and transmission. You should inspect and service your oil cooler regularly to avoid major failures.

Oil coolers are most common in heavy-duty commercial vehicles that have an industrial-grade engine. These engines usually produce more power than their standard counterparts. This can lead to the engine oil becoming too hot and not lubricating the way it should. The solution is an engine oil cooler.


Some vehicles that rely on oil as a coolant include:

  • Trucks for towing or used to haul freight
  • Large vehicles designed for off-roading
  • Some RVs
  • Some racing or sports cars


Types of Engine Oil Coolers

There are a few styles of engine oil coolers:

Filter Mounted

Engine oil leaves the engine and moves to the oil cooler. There it circulates through the oil cooler, leaves, and enters the oil filter. The oil is filtered and returns to the engine through the hollow mounting bolt. Cooled fluid comes from the radiator circuit.


Mounted inside one of the radiator tanks, oil lines are routed to the oil cooler, and oil flows through the inside of the oil cooler. At the same time, cold water in the radiator tanks flows around the outside of the oil cooler.

Remote Mounted

Mounted remotely from the engine block or transmission case.

There are two kinds of designs and mounting strategies in this type of engine oil cooler:

  1. Air Cooled—Mounted directly in an air stream: These are most often in front of the radiators, so they can receive air flow through them. To achieve cooling, hot oil passes through the cooler via external fluid lines from the engine or transmission, while ambient air passes through the core of the oil cooler. This type of cooler is available in a range of sizes, depending on how much you need to cool the oil.
  2. Water Cooled Oil—Liquid-to-liquid remote oil cooler: Engine or transmission oil and coolant are both fed to the oil cooler through fluid lines coming from the oil and coolant circuits. It can be mounted anywhere there is room under the hood. Instead of relying on airflow, like the radiator type of oil cooler, they connect to the vehicle's cooling system and use the coolant to keep the oil temperature down. This style of oil cooler is more compact in size and is more commonly used in vehicles where space is a premium.


Engine Mounted

This engine oil cooler is commonly used on diesel, gasoline or flex fuel engines for passenger vehicles and light trucks needing engine oil cooling capacity. This design also works well for new, efficient engines requiring engine-mounted oil coolers.

Mounted directly onto the engine block, engine oil leaves the engine and enters the oil cooler, circulates through the oil cooler, leaves the oil cooler, and re-enters the engine. The cold fluid can be routed to the heat exchanger in two ways.

  1. It can be fed from the radiator circuit through flexible lines.
  2. It can be fed directly into the heat exchanger from the engine block, eliminating the need for additional lines.


Common Problems

Motor oil lubricates and cleans the metal surfaces that move and create heat and friction. As motor oil heats up, it loses its ability to lubricate, and the surfaces that require lubrication begin to wear. Engine oil coolers function to prevent or delay oil from getting to a critical break-down point.

The most favorable temperature for oil is usually between 180° and 200°F. Failures start to happen when oil can’t deplete its heat quickly, allowing it to rise past the optimum temperature range, which can start to degrade the oil. Oil loses its lubricating and cooling properties when it starts to break down, and this can lead to a number of serious transmission and engine problems.

McDowell says: “The most common failures of oil coolers are rusting through from the outside, internal cracking of the coolant tubes or plates. Often times, this causes engine oil to be forced into the cooling system, overfilling the radiator or contaminating the coolant.

Important Part of Your Engine's Operation

By replacing the oil cooler, you’ll help to improve your engine oiling and improve the oil quality running through your injectors.

Oil Cooler Kit | Highway & Heavy Parts



Ask us about our Oil Cooler Install Kits!

HHP sells Engine Oil cooler replacements and other engine cooling components such as EGR coolers, water pumps, and thermostats.

The only difference you'll see with our replacement oil coolers and components is the lower price.

HHP Oil Coolers are built to withstand even the toughest abuse.


Highway & Heavy Parts has quality NEW Engine Mounted Engine Coolers at manufacturer direct prices.


  • Cost Savings of 30-40%
  • Built to OEM specifications
  • Fast Shipping
  • Lower and control engine oil operating temperature to extend engine life
  • Enable robust, highly fuel-efficient engine performance

If you're looking for a new oil cooler, give us a call at 844-304-7688. One of our certified techs can help you find the right fit for your engine. Or, you can always request a quote online

Originally posted September 21, 2015, Updated March 5, 2019