it depends on a lot of different things could be a bad or old hose or crank case pressure due to a cracked head,or a hole in a piston.
engine light comes on and off. when light is on it hesitates and transmission slips. what could cause that on a 93 F150
The thermostat may be stuck open.
The most common cause of this failure is a broken blend door. Check heatertreater.net for diagnostic information and an inexpensive fix.
In front of the radiator
The radiator only, aprox 4 qts.
more likely to need a new thermostat in engine , than an air lock.
The thread on cap on your engine coolant reservoir is your pressure cap / radiator cap
The thread on cap on your engine coolant reservoir is your pressure cap / radiator cap
bolted in from new
Follow the top radiator hose to the thermostat.
check your thermostat, if that isn't it you might need a new heater core. had one put in my f150 for about $150. With my car, it was Heater matrix clogged with radiator sealant. The workshop cleaned it and it's start working fine!
is the new thermostat rated to manufacturers specs? if so it coul be air in your coling system causing hot spots.or it could also be low/contaminated fluid. also check the radiator for leaks just had that problem was a small crack in plastic side casing of radiator.