The thermostat might be installed backwards. The thermostat will still work, but not as efficiently as if it were installed properly. It sounds like engine is still not receiving proper water flow. This is a common mistake.
No coolant Thermostat not opening Defective temperature sensor
Low coolant? Thermostat not opening? Water pump not circulating coolant?
Low coolant? Cooling fan not working? Thermostat not opening? Water pump not circulating coolant?
No it should fit into the housing along with the thermostat. Try putting the rubber in first, then the thermostat. remember the rubber is malliable so it will conform to the opening, then insert the thermostat
Check the water pump
Thermostat may not be opening
The top radiator hose is above the thermostat. If the top radiator hose is hot, the thermostat is opening. The thermostat is not the problem. Perhaps the radiator is clogged up or the water pump is bad. Look elsewhere.
Your thermostat is possibly not opening up. Replace and flush and then recheck. Good luck.
I don't own a 1993 Nissan Pickup Truck, stupid! check your thermostat to see if it opening
Drain approx. 1 gallon from radiator prior to opening housing
Could be a bad thermostat-not opening
Check to make sure you have the correct mixture of anti-freeze and water because anti-freeze also helps with overheating too. If you still have a problem check your thermostat. It could be stuck closed and may not be opening.