Oil Cooler Kits

An oil cooler is a heat exchanger that transfers heat from engine oil to either coolant or ambient air. In a diesel engine, oil operates under significantly higher thermal stress than in a gas engine — higher compression ratios, greater cylinder pressures, and sustained load conditions (towing, hauling) push oil temperatures well beyond what a standard oil pan can manage alone.

Signs your truck could benefit from an upgraded oil cooler:

• Oil temperatures regularly exceeding 240°F during normal driving or towing
• Long mountain grades cause the oil temperature gauge to climb toward the red
• Extended idle times in hot climates — diesels running under load generate enormous heat with minimal airflow
• Frequent short-trip driving where oil never fully reaches operating temperature, leading to fuel/water contamination
• Running a tuned truck with increased combustion pressures and higher horsepower output

Stock oil coolers are sized for stock conditions. If you tow, live in a hot climate, or have added a tune, an aftermarket oil cooler is one of the best ways to protect your engine long-term — keeping oil within its optimal temperature range (210–230°F) extends oil life and reduces internal wear.

Oil cooler kits vary by platform and application. Here is a quick reference for the major diesel platforms:

• Ford 6.0L Powerstroke (2003–2007): The 6.0L oil cooler is one of the most notorious failure points in diesel history. Clogged coolant passages in the oil cooler cause oil to overheat, leading to head gasket failure and EGR cooler ruptures. Bulletproofing a 6.0L almost always includes an oil cooler replacement or external oil cooler upgrade. This is not optional — it is mandatory for a healthy engine.
• Ford 6.7L Powerstroke (2011–2024): The 6.7L has a more robust factory oil cooler than the 6.0L, but heavy towing and tuning still push it past its limits. Mishimoto and SPELAB both offer external oil cooler kits as supplements to the factory unit for owners running tunes or frequently towing near maximum GCWR.
• GM Duramax (all generations): Duramax oil cooler failures can be catastrophic — when the oil cooler clogs or fails, oil supply to the engine is disrupted, leading to immediate engine failure. The LML (2011–2016) and L5P (2017+) are particularly sensitive to oil cooler issues under high-load conditions.
• Dodge Cummins 6.7L (2010–2024): The 6.7L Cummins benefits from a factory oil-to-coolant oil cooler, but upgrading to a larger-capacity external oil cooler reduces oil temps under sustained heavy loads and extends the life of both the engine and the turbocharger.

When purchasing an oil cooler kit, confirm your exact engine platform, model year, and whether you need a coolant-to-oil cooler (factory-style) or an air-to-oil cooler (external, mounted in front of the radiator).

An oil cooler failure does not always announce itself with a warning light. Watch for these symptoms:

• Oil temperature spikes under load: If the temperature gauge climbs rapidly when towing or climbing grades, the oil cooler may be restricted or failing
• Coolant contamination: Milky-colored coolant or oil showing up in the coolant overflow bottle — a cracked oil cooler core allows oil and coolant to mix, which is catastrophic for both systems
• Low oil pressure: A failing oil cooler can restrict oil flow to critical engine bearings, causing pressure drops especially at idle and under load
• Excessive oil consumption: Oil coolers that develop internal leaks consume oil by feeding it into the cooling system rather than burning it in the combustion chamber
• Oil smell in the coolant: Radiator overflow tanks that smell like burnt oil are a strong indicator of oil-cooler-to-coolant leakage

If you notice any of these symptoms, stop driving immediately. An oil cooler leak that cross-contaminates your oil and coolant can lead to engine failure within minutes. This is not a repair to delay.

Both options have their place depending on your truck's situation:

• OEM replacement: Use an OEM oil cooler (Mopar, Motorcraft, ACDelco) if you are replacing a failed unit on a stock truck. OEM coolers match factory specifications exactly and are the safest choice for warranty-covered vehicles. For the 6.0L Powerstroke, Ford's updated oil cooler design (post-2005 revisions) is significantly more reliable than earlier versions.
• Aftermarket upgraded oil cooler: Choose an aftermarket kit (SPELAB, Mishimoto, BD Diesel, Banks Power) if you want to supplement or replace the factory cooler with a higher-capacity unit. Aftermarket options offer:
  
  Greater heat dissipation capacity for modified and heavy-duty builds
  Thermostatic bypass valves to warm the engine faster in cold climates
  External mounting for improved airflow and cooling efficiency
  Stainless steel construction for corrosion resistance
  
  

Bottom line: Replace with OEM if you are doing a one-time repair on a stock truck. Upgrade to an aftermarket kit if you are building a performance diesel, regularly tow near max capacity, or own a 6.0L Powerstroke.

Installing an oil cooler kit ranges from moderate to advanced difficulty depending on the platform:

• Difficulty level: Intermediate to advanced — this is not a beginner project
• Time required: 3–8 hours depending on platform and whether you are replacing the factory cooler or adding an external supplemental cooler
• Platform-specific notes:
  
  6.0L Powerstroke: Requires draining coolant, removing intake or valve cover for access, and bleeding the cooling system after installation. Often combined with EGR cooler deletion for a full repair package.
  6.7L Powerstroke and Duramax: External oil cooler kits are mounted in front of the radiator — more accessible but require routing coolant lines through the engine bay.
  Cummins 6.7L: Factory oil-to-coolant cooler is integrated — adding an external air-to-oil cooler is the most common upgrade approach.
  
  
• Critical step: Bleeding air from the cooling system after installation. Air pockets in the coolant lines can cause overheating and damage. Follow the kit instructions carefully, and consider having coolant flow checked at a shop if you are unsure.

If you are not comfortable working with coolant systems or need to remove major engine components for access, this is a job for a diesel mechanic. The cost of professional installation (typically $200–$500 labor) is a worthwhile investment compared to the damage caused by an improperly installed coolant system.