Used Hydraulic Oil Cooler and Oil Radiator

Types of coolers: hydraulic air/oil heat exchanger or water/oil

On most construction machinery, the hydraulic oil cooler is an air/oil heat exchanger: the oil circulates through a tube and fin bundle, often made of aluminum alloy, which is crossed by fan-driven air. Heat exchange occurs through the bundle’s walls. This aluminum radiator is usually mounted as a single unit with the water radiator and the charge air cooler, placed either in front or behind them depending on the brand. Some machines feature a combined bundle, while others have a separate oil radiator mounted on its own frame. The water/oil cooler, more compact, is still rare on mobile machinery. In hydraulic systems of machines, the heat exchanger is installed on the hydraulic return line, before the filter and reservoir. A bypass valve protects the bundle when the oil is too thick during cold starts or when a pressure spike occurs.

Fans for hydraulic radiators and hydraulic coolers – 12V and 24V

• Engine-driven fan: on older machines, it runs continuously with the thermal engine via a belt.
• Hydraulic fan: on recent excavators and loaders, a hydraulic motor drives it at a speed controlled by oil and water temperature. Some models reverse the rotation direction to clean the bundle.
• 12V or 24V electric fan: found on mini excavators and hydraulic coolers added later. Most excavators and loaders use 24V: verify the voltage before ordering.
• A fan not running at full speed causes the oil to heat up as much as a clogged bundle.

Identifying the right oil radiator before ordering

Two hydraulic oil coolers that look similar are not necessarily interchangeable, as hydraulic systems from the same brand can vary between series. Cooling capacity depends on the bundle size and must match your circuit’s oil flow. Measure the height, width, and thickness of the bundle, then note the position and diameter of inlet and outlet fittings, as well as their type: flange, threaded fitting, or collar-ended fitting. Also record the position of mounting brackets, since the radiator must align with other bundles in the cooling block. Finally, note the reference engraved or labeled on the frame and the machine’s serial number. With this information, our advisors can find the original oil radiator or a model with the same dimensions.

Oil radiators dismantled by brand and model

• Caterpillar: excavators 308E2CR, 323F, 336EL and 345CL, wheeled excavator M313D, loaders 963C, 966K and 972M
• Volvo: excavators ECR145EL, EC210BLC and EC380EL, loaders L110F and L120E
• Liebherr: excavators R956HD and R974C, crawler loader LR622
• Komatsu PC228USLC-11 and WA320PZ-6, JCB 436 and JS330XD, Mecalac 714MW and 12MTX
• Hitachi ZX250LCN-3, New Holland E135B, Case WX145 and other brands: inquiry available on request from dismantled machines

Hydraulic oil radiator for mini excavators

On a mini excavator, the hydraulic oil radiator is smaller but works within a tight hood, close to the engine, where dust accumulates quickly. It is often combined with the water radiator in one unit, sometimes with an electric fan. Models around 8 tonnes, like the Kubota KX080-4, are offered depending on stock. For mini excavators, fitting the position of connections and block size is as important as the bundle’s dimensions. For diagnosis and maintenance, read our article on the mini excavator radiator.

What are the symptoms of a faulty oil cooler?

• Oil traces on the bundle or at the bottom of the cooling block: cracked tube or leaking weld.
• Oil temperature warning light comes on during continuous operation while the fan runs normally.
• Movements slow and feel sluggish when the machine is hot, pump gets noisier, risk of cavitation.
• Fins flattened or corroded over a large area, cleaning no longer effective.
• Connection torn off or frame cracked after impact or vibrations.

Repairing or replacing the oil radiator

A bundle clogged simply with dust can be cleaned with compressed air or low-pressure water, against airflow, without bending the fins. A leak on a tube or weld can sometimes be repaired in a specialized workshop, but repair remains uncertain on an aluminum bundle already fatigued by heating cycles: its lifespan mainly depends on vibrations, oil cleanliness, and bundle maintenance. In that case, a used original oil radiator taken from the same model can be refitted without adapting mounts or hoses. As with all hydraulic systems, flush the circuit and change filters before reassembly: debris from a pump or a worn hydraulic motor would quickly clog the bundle.

Requesting an oil radiator from our advisors

• The brand, model, and serial number of the machine.
• The bundle dimensions and position of the fittings.
• A photo of the radiator in place and its label or plate.
• Specify if you need the oil radiator alone or the complete block with water, oil, and air.

Our advisors search among approximately 17,000 references of used spare parts and answer at 05 18 23 21 34.