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Main Causes of Overheating For medium duty truck

Frequent, short distance trips (less than 10 miles), can take a toll on a vehicle.  Short drives in stop and go traffic are considered severe duty operating conditions, which subjects your work truck’s engine to increased wear and tear.  Medium-duty trucks that operate under these parameters are most likely to experience an overheating condition without regularly scheduled maintenance.

Here are three main reasons why medium-duty truck engines may overheat:

1. Air Pockets

Engine Coolant helps regulate temperatures and carry heat away from the engine to be cooled in the radiator of your medium-duty truck’s engine.  And when you work on any part of the cooling system, there is a possibility for air pockets to occur, which reduces the total amount of coolant in the system, and prevents your engine cooling system from operating optimally.

This reduction ultimately causes your engine to generate excess heat that is not effectively dissipated.  You need to make sure that the air is purged from the system when you’re replacing any part of your cooling system.  Here are some tips on how to do that:

  • Double-check coolant level after a complete drive heat cycle and motor cool down.
  • Check the temperature gauge frequently.
  • Make sure the heater is on during several trips to move any air out of the heater core.
  • Open any bleeder valves after completing a cooling system repair if applicable to your truck.

If the problem persists, maybe it’s time to start thinking, “Where can I find the best medium duty truck engine repair near me?” and get your truck to the repair shop to save your engine.  The best way for you to diagnose cooling system air pockets is to have your truck regularly serviced so you can minimize the chances of any cooling system failures from happening.

2. Stuck Thermostat

A thermostat works to make sure that engine temperatures stay at a specific safe range. Properly working thermostats doesn’t fully close or open, allowing for optimal coolant flow.

On the other hand, a faulty thermostat may be stuck in either an open or closed position, causing coolant to flow excessively or not at all.  Both of these can cause your medium-duty truck’s engine to overheat, and suffering possible engine damage such as a blown head gasket due to the cylinder head(s) being warped from a high heat condition.

Thermostat failure and continued driving while a failure has occurred is one of the most common causes of overheating.

Don’t let this happen.  Start thinking, “Where can I get a reliable engine repair near me?”  And once you find a qualified service center, have your thermostat replaced, and make sure that you get the best expert engine repair  that OKC has to offer.

3. Faulty Electric Cooling Fan

An electric cooling fan attaches to your truck’s radiator.  It turns on to keep your medium-duty truck cool when it reaches a particular temperature while at idle or when the coolant levels are not enough to regulate the engine’s temperature at the pre determined operating range set point.

When a cooling fan is defective, it will not turn on in any of those situations, causing your engine to overheat and may affect other components like the thermostat, radiator, and cylinder head.

To diagnose the problem, take your truck to a qualified truck service center. If the fuse isn’t the culprit, the service center will check the cooling system’s sensors, and check the fan motor for possible electrical issues that may require replacement of the cooling fan motor.

4. Improper Belt Tension

The belt(s) also play a significant role in the cooling system, and the belts need to have the proper tension to turn accessories such as the water pump at the required speed to move coolant through the system. If the belt tensioner is failing or the belt condition is poor, this will cause slippage and the water pump will not function properly and aid in creating an overheating condition. The belts also turn the power steering pump, A/C compressor, and the alternator as well. With so many accessories relying on the belts to operate, it would be a wise choice to have your truck serviced by a qualified truck repair facility.


Whether you own a single truck or an entire fleet, engine problems can be extremely expensive, primarily when you don’t address those issues immediately.

When your commercial medium-duty truck starts showing the signs of trouble described in this post, don’t take any chances.  Stop your engine from suffering more wear and tear.  Schedule a service appointment or drive to a facility that offers top quality engine repair that OKC residents trust.  Contact Truck-N-Trailer Service today at (405) 912-5800 or at


Author admin-oktruckrepair

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