Towing is one of the greatest strengths of Powerstroke and Cummins diesel trucks but it’s also one of the most demanding conditions for your engine and cooling system. Even the toughest setups can start to show signs of strain when hauling heavy loads, especially in hot weather or steep terrain.
At Bullet Proof Diesel, we’ve worked with countless truck owners who’ve experienced overheating while towing, and most of the time, the root cause isn’t the truck’s power—it’s the cooling system’s limitations. In this article, we’ll explain why trucks overheat when towing, what signs to watch for, and how to prevent it with proper maintenance and upgraded components.
Why Do Trucks Overheat When Towing?
When you hook up a trailer, camper, or boat, your engine suddenly works much harder. The added weight increases combustion heat, puts extra strain on the transmission, and challenges the cooling system to keep temperatures in check.
If one part of that system isn’t performing at its best—whether it’s the radiator, oil cooler, water pump, or fan clutch—temperatures can climb fast. Modern Powerstroke and Cummins engines are designed to run hot under load, but persistent overheating signals that the system can’t dissipate heat efficiently enough.
Top Causes of Overheating When Towing (Powerstroke & Cummins)
1. Clogged Radiator or Restricted Airflow
Dust, mud, and debris are common culprits. When airflow across the radiator is blocked, heat can’t escape efficiently. This is especially common for trucks that tow off-road or in construction environments.
Tip: Regularly clean your radiator fins and intercooler to restore full cooling efficiency. There are radiator cleaning wands and even “coil and fin” liquid cleaners available online.
2. Weak or Failing Water Pump
A worn-out water pump can’t circulate coolant effectively. Factory pumps often use plastic impellers that degrade or crack over time—especially under heavy towing loads.
Upgrade Solution: The Bullet Proof Diesel Water Pump for the Cummins and Powerstroke engines replaces plastic impellers with a metal design, improving coolant flow and long-term reliability.
3. Oil Cooler Restrictions
The engine oil cooler regulates oil temperature by transferring heat to the coolant. Over time, factory coolers can clog with debris or contaminant buildup, leading to heat retention and rising oil temps.
A restricted oil cooler can also raise exhaust temperatures, further compounding the problem.
Upgrade Solution: The Bullet Proof Diesel Oil Cooler Kit for the Powerstroke engines, improves coolant flow and eliminates internal clogging points.
4. Faulty Fan Clutch or Cooling Fan
If the fan clutch fails to engage, airflow across the radiator is drastically reduced. This is one of the most common reasons Powerstroke and Cummins trucks overheat under load.
5. Old or Contaminated Coolant
Coolant loses its protective properties over time. Old or low-quality coolant can form scale, restricting flow through the radiator and cooler passages. Always use OEM-spec or upgraded coolant designed for diesel applications.
6. Transmission Heat Load
When towing, your transmission generates significant heat. Without proper cooling, it can push overall engine temperatures higher. Trucks equipped with auxiliary transmission coolers handle towing heat far more effectively.
- Warning Signs of Overheating While Towing
- Rising coolant or oil temperature gauge
- Engine fan running constantly
- Reduced power output or limp mode
- Steam or coolant odor near the hood
- Transmission shifting erratically under load
If you notice any of these symptoms, pull over and let the truck cool before continuing. Driving through an overheat can warp cylinder heads, cause head gasket failure, damage the turbo, or even cause major engine damage.
How to Prevent Overheating When Towing
Perform coolant flushes or complete system fluid changes every 2–3 years.
Keep your radiator, intercooler, and oil cooler free of dirt and buildup.
Replace weak or aging water pumps before a major trip.
Consider upgraded oil coolers and water pumps from Bullet Proof Diesel for heavy towing reliability.
Monitor oil and coolant temperatures using a scan tool or gauge while towing.
These preventive steps ensure your Powerstroke or Cummins stays cool, even when hauling at full capacity.
Final Thoughts: Keep Your Truck Cool Under Pressure
Towing puts your engine and cooling system to the test but overheating doesn’t have to be part of the job. By understanding the most common causes and upgrading weak components, you can keep your Powerstroke or Cummins running cool and confident mile after mile.
At Bullet Proof Diesel, we design components that eliminate the weak links like plastic impellers, restrictive oil coolers, and undersized bearings so your truck performs the way it should, even under the toughest towing conditions.
Disclaimer
This content is provided by Bullet Proof Diesel for informational purposes only. Always consult your vehicle’s owner’s manual or a qualified diesel technician for specific diagnostics or repairs.
FINAL THOUGHTS
Towing doesn’t have to overheat your truck. Upgrading weak OEM components prevents costly failures.
