This is just a general question. What are the main reasons for engine overheat, especially in diesel vehicles? My truck has this problem. It is an F-150 truck. I don’t think it is due to some issues in air filter or coolant level, I already checked all these things. I guess people who have knowledge in car maintenance services can help me with an answer. Thank you in advance.

 

If you have limited knowledge and tools to work on these engines, it is best to have someone with the knowledge and experience look at it.
Among the list of possible causes:
defective thermostat
water pump problem
blocked radiator
low coolant level
compression getting into the cooling system
poor cooling system maintenance
drive belt slipping, to name a few !

 

F150s don't come with diesel engines. But diesels can run hot for the same reasons as gas engines. Read this:
The Coolant System Explained