Keep Your Cummins X15 and ISX Running Cooler, Longer

If you’re searching for how to reduce oil temperature in Cummins X15 or wondering why your ISX oil temperature is running too hot, the PDI Big Boss Performance Dual Oil Cooler is your answer.

This premium upgrade is engineered specifically for 1999–2024 Cummins X15 and ISX engines. Whether you’re pushing hard on long hauls or hauling heavy loads, overheating oil can be a costly problem. This high-efficiency dual oil cooler is designed to fix that—fast.

Key Features & Technical Benefits

• Dual High-Efficiency Cooler Packs
  Doubles the cooling surface area to maximize thermal efficiency under extreme conditions.

• 75% More Oil Cooling Capacity
  Compared to the stock Cummins cooler, this unit drastically improves oil heat dissipation.

• Lowers Peak Oil Temps by 20–30°F
  Maintain oil closer to your thermostat setting and avoid reaching breakdown temperatures of 255°F+.

• Thermostat & Bypass Valve Included
  Ensures smooth integration into your engine’s cooling system with OEM-style reliability.

• Complete New Casting & Assembly
  Not a reman or reworked core—this is a 100% newly engineered assembly made for performance.

• Built in the USA
  Proudly manufactured to deliver American durability, backed by a 1-Year Unlimited Mileage Warranty.

Why Your Diesel Needs This Oil Cooler

If you’re experiencing:

• Overheating engine oil on long pulls

• Degraded oil performance over time

• Loss of power during heavy loads

• Unstable oil pressure readings

…it’s time to upgrade. This performance dual oil cooler is designed to stabilize oil temps, extend oil life, and protect your engine investment.

OEM Reference & Compatibility

Compatible With:

• Cummins X15 & ISX Diesel Engines (Model Years 1999–2024)

• On-highway, off-road, and performance-tuned applications

OEM Cross Reference Numbers: 4386026, 4386025, 4386199, 4955831, 4965896, 4089583, 4965906, 4965895, 4955830, 3682787, 3682788, 4920199, 5394142, 4952498

Warranty Coverage

Enjoy peace of mind with PDI’s 1-Year Unlimited Mileage Warranty. Built to perform, built to last.

Talk Diesel, Run Cool

Whether you’re upgrading for performance, preventing future damage, or replacing a failing unit, the PDI Big Boss Performance Dual Oil Cooler is the smart move for serious diesel drivers.

Ready to upgrade your Cummins oil cooler setup?
Need better temperature control under load?

This is your solution. Add it to your cart today and drive with confidence.