1987 gauge, truck gradually goes up in temp until it reaches the “N” top area near the (NORM) area. Or near the H for Hot. It gets hot at high RPMS (2500-3) but at a red light or idle it’ll cool down again relatively quickly. Only takes about 15 minutes to reach the middle point in gauge. After a 60 mile trip about 20 miles in it was at the near Hot mark & ran for so the rest 40 miles. Doesn’t reach the overheating point but I know it’s running hotter than should be. When I got home I noticed the radiator cap was cold. Already changed the thermostat and water pump doesn’t leak or otherwise indicate it’s faulty.


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1987 single cab ford ranger
4 cylinder
2.30 L
5 speed manual
2 wheel drive - rear

Could be air caught in the system.
Possible blocked coolant passage in the radiator. 34 year old truck you know.
Check the clutch fan.
New water pumps and thermostats made in corona virus land have been known to be bad right out of the box.

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What does the temperature of the air blowing past the radiator feel like? Most times when you overheat in traffic, it is pump related, while overheating on the highway indicates a radiator problem.
A cold radiator cap indicates there is no heated coolant at that point. Even with a good slug of air in the system, most times the metal of the tank will get hot. The heated water from the engine should be flowing through the thermostat, the upper radiator hose, and into the top tank. It then flows down the tubes, and out the lower hose into the pump inlet, pushed around the engine, and then back out through the thermostat. If the coolant level is visible in the upper tank, try squeezing the upper hose to see if it is full of coolant also, it should cause some flushing and movement of the coolant in the tank.
Check the temperature of the upper radiator hose from cold, monitor over the engine warmup time. It should stay cold and then quickly get hot as the thermostat opens. If it warms slowly, the thermostat is leaking coolant when it should be preventing flow.
tom