Have you actually check that your engine IS hot with a thermometer?
It could be that you have a bad temperature gauge, a bad sensor, or a bad connection in the wiring or something.
How is your coolant level? Maybe you have a leak somewhere (internal/external). I suppose that's the first thing you checked though.
Other possible problems:
*you serpentine belt is slipping on the pulley resulting in the water pump no working properly (check you tensioner). Speaking about pulley, your water pump pulley is the original one right? (Or at least an original replacement, same size etc.).
*your electric fans don't come on
*bad radiator cap
*glogged water jackets in your engine
Since you've replaced the water pump, radiator and thermostat, these are the other reasons I can think of.
I suggest you pressure test your cooling system to check for leaks.
Wednesday, October 24th, 2018 AT 1:30 PM