I have a 1987 Dodge Ram that overheats when ever I drive it for about 15 minutes and I have checked the coolant level and it is at the appropriate level. What could I do to stop it from overheating? My friends say it's the thermostat but I would like some more opinions on it before I spend money on something that doesn't need replacing

I have a 1987 Dodge Ram that overheats when ever i drive it for about 15 minutes and i have checked the coolant level and it is at the appropriate level. what could i do to stop it from overheating? my friends say it's the thermostat but i would like some more opinions on it before i spend money on something that doesn't need replacing
Probably needs a new radiator.

Considering the year and if you don't know when or if the thermostat was ever replaced it's very possible that it the thermostat.But it could be a number of other things too: like the drive belt, if it is glazed or cracked or stretched it may slip.The belt adjuster has an indicator and pointer that lines up when the belt needs replacing.The fan clutch if it has one might be bad.Improper grade of engine oil could also be a problem.