My 2002 sentra gxe with 130k randomly reads hot. The actual value with a scan tool read 84C when it was occuring.The thermostat and the temperature sensor have been replaced. The problem still persists. There is no oil in the coolant, or coolant in the oil. Anyone have an answer, or experience with this issue?

some times after market senders read hotter if there not quiet the same value

I would suggest having the engine temperature sensor and circuit checked, as well as your engine temperature guage. The guage is best checked with the use of a scan tool used by the dealer or a repair facility. If no signs of actual malfunction of the vehicle are present, you may just be throwing money at the car because of a false reading on your temperature guage. Some cooling systems require a specific filling procedure. If not done properly, air will be trapped in the system, causing similar issues to what you are experiencing. That would also cause loss of heat in the cabin, as well as overheating of the engine.

Hello
The engine and automatic transmission in this vehicles drive train are fully electronically controlled by a computer called the PCM (Power Train Control Module). Whenever a problem like this occurs the computer stores a record of the problem (there are of course some exceptions to this, like the fuel pump, engine coolant temperature sensor and MAF sensor for instance) in the form of a fault code in its memory, to read these fault codes you must have the systems memory scanned with a special tool. Once the fault code(s) are read you then must perform the appropriate diagnostic testing to find and resolve the problem(s) DO NOT REPLACE ANY PARTS UNTIL A TRAINED TECHNICAIN HAS DIAGNOSED THE PROBLEM TO AVOID SPENDING YOUR HARD EARNED MONEY ON PARTS THAT MAY NOT CORRECT THE PROBLEM

O2 sensor/s faulty

are the upper and lower radiator hoses hot when car overheats? if so check for a clogged radiator or weak water pump. if one hose is hot and the other is cold or much cooler then replace the thermostat.

That is actually normal, but it usually works a little slower, have the temperature sensor and thermostat replaced and it will work normal again

Take a few minutes to make sure you dont have a blown fuse....Run through them with your test light...

you could have an air pocket in the cooling system that has to be burped. With a cold engine, park uphill and leave the radiator cap loose. Fill radiator and coolant reservoir. Start engine with cap loose and run at 1500 rpm until temp gauge reads normal. Feel if top radiator return hose from engine to radiator is hot. If yes, coolant is flowing and thermostat is open. If cold, thermostat is not staying closed until engine is hot.

report results.

Hi! yeah this might help... but your radiator does'nt dissolved much water because of formed scale deposits.... try to drain or maybe check for leaks before changing the thermostat... Thermostat don't easily broken....

My 2005 Nissan Sentra 1.8s with 55,000 mi. blows cold air from the heater. Coolant not circulating in engine. Lower hose stays cool to touch. Both heater hoses cold. Changed thermostat - didn't fix it. Coolant not leaking or dirty. None in oil - no oil in radiator. Changed worn water pump belt - pump spins freely with no noise or resistance. Cooling fans come on after warm-up. Temperature gauge stays in normal range then jumps to hot and back again. Coolant good to 10 below - didn't freeze here yet. No other problems or repairs to car. Afraid to drive and make worse. Help!