Radiator problems 2001 Chevy Tracker Only the top radiator hose gets hot,the bottom one never gets hot, but my temperature gauge stays where it should... i changed the rad,water pump and thermostat, I'm just wondering if the thermostat could be faulty

The temperature switch on the side of the upper radiator hose is not working. That is, if the engine is hot. Boiling over - need to check thermostat. Grab on to upper hose (should be hot) than with engine off, grab bottom radiator hose. It also should be same temperature as top. If so, thermostat ok. Electric radiator fan - turn Ac on. Fans should run. No, check fuses & relay. Mechanical fan - with engine off, the blade should be stiff to turn. Easy, replace fan clutch. Usually, low level of water is most common. Wish you well.

Did you put the thermostat in backwards? If you did, it wont open when hot. Thermostats look pretty much the same - with some minor variations. It's important to note the the side with the spring should be facing the (hot) engine and the other side facing the (cool) radiator as shown in the image below. If the spring side doesn't get hot - it won't open to let hot water from the engine flow to the radiator for proper cooling.

Try disconnecting the sensor. then turn on the ignition switch and see what the guage dose. If it still goes to the top, chances are there is a short in the wiring. If it does nothing, chances are you have a defective sensor.

sounds like the thermostat may not be opening.

Have you checked the engine temperature when the gauge shows fully high if it is true message and not lying and the problem is the temperature gauge? Since this happened stop the car open the bonnet touch the radiator hoses and even with off running engine touch the vents of the radiator to all surface and see it the temperature is everywhere the same.

you need to replace thermostat and radiator cap.look under hood around engine compartment.look for a radiator cap near radiator,add 50/50 antifreeze and water to coolant system to bring up boiling point.pure water will cause engine run hotter because water evaporate away,remove radiator pour coolant in the radiator until coolant stop dropping in the radiator now some vechicle pour coolant in the coolant overflow jug,pour coolant until coolant level stop dropping and the coolant level stay at cold full mark.start engie let idle few minutes, watch coolant level in radiator if coolant start dropping add more coolant, when coolant level stop dropping put radiator cap back on let engine idle until both top radaitor hose and bottom coolant hose get warm turn off engine wait until it get cool then take a large rag slightly open radiator just a litle at a time to keep from getting scaled.once radiator remove add more coolant if low,put radiator cap back on start the engine let it idle watch the temp gauge if temperature gauge going hot zone stop engine wait until cool then add more coolant,keep doing this until engine stop overheating going into hot zone and coolant level stop dropping,make the coolant overflow jug coolant level stay at full cold mark, dont let jug run empty if so air will get in the coolant system causing engine to overheat.

I agree, sounds like the radiator is bad. Not only is the outside not disapating heat but it may be blocked in the coolant tubes. I'd replace it.

YOU NEED BLEED COOLANT SYSTEM.CHECK COOLANT LEVEL IN RADIATOR.ADD MORE DEXCOOL UNTIL COOLANT LEVEL IS CLOSE TO RADIATOR SPOUT.CRANK ENGINE LET IDLE UNTIL TOP RADIATOR HOSE GET HOT.WATCH TEMPERATURE GAUGE.IF TEMPERATURE GAUGE START RISING TO HOT ZONE.TURN OFF ENGINE.LET COOL DOWN.USE LARGE RAG SLOWLY OPEN RADIATOR CAP A LITTLE AT A TIME UNTIL ALL PRESSURE RELIEVED.REMOVE RADIATOR CAP.ADD MORE COOLANT.CRANK CAR AGAIN LET IDLE UNTIL TOP RADIATOR GET HOT.KEEP EYE ON TEMP.GAUGE ALSO.WHEN TEMP.GAUGE STOP CLIMBING.YOUR COOLANT SYSTEM BLED.WHEN DONE LET CAR SET A WHILE CHECK COOLANT LEVEL.ALSO FIRST THING IN THE MORNING CHECK COOLANT LEVEL AGAIN.AND BESURE ADD COOLANT IN THE OVERFLOW JUG TO THE COLD MARK.DONT OVER FILL THE COOLANT RESERVOIR JUG.WORK SAFELY DONT GET SCALDED.

Sounds to me your water pump impeller has come off the water pump.The only way is to change the water pump.Hope that was helpfull.

Sounds like the water pump.Check if you see coolant or coolant residue behind the water pump pulley.