Got a pre-owned nissan sentra 2001 gxe. Everything works but Heat. Engine was getting overheated ,2 miles driving can make the temp to H. checked upper hose was hot and lower was cold. took it to the mechanic thermostat changed. Heater and radiator worked for 10 min GOOD and still the same no heat and engine over heating. Took the car to mech now he changed water pump. car ran for 20 min GOOD and again no heat ,upper hose hot and lower hose cold, funny thing is that ,that the temp is fluctuating very easily . highway driving brings temp sometime down and any lower speed brings temp to H. noticed all time fan worked at high temp. so conclusively ,coolant full, fan works,upper hose is hot and lower hose is cold, no heating in the car, temp is fluctuating crazily ,water pump new, new thermostat installed, NOW WHAT COULD BE A PROBLEM??? ANY EXPERTISE OR HELP/ SUGGESTION/ ADVISE!!!!!

SOURCE: 2004 NISSAN ALTIMA 2.5 NO CABIN HEAT..ENGINE AT OPERATING TEMP.

If the engine is not over heating than most lilely it isn't the thermostat or waterpump that is causing the problem. Check the heater hose coming out of the manifold and see if it is warm to hot. Next check the return line from the heater if it is still cold or moch cooler than the inlet, the most possible problem is the heater water control valve if this model has one or possible the core of the heater is plugg with slime cause by some antifreezes setting during the summer months while not being used. If this is the case than remove tihe two hoses and back flush the heater core with water pressure until it runs clear. I have had this problem before and this cured my problem. I also had to flush the engine and radatior also. Hope this help. .

SOURCE: 2003 Nissan Sentra Problem overheating and heater doesn't work.

I had this exact problem a few weeks ago. The repair shop first changed the thermostat. Didn't fix the problem. Next step, they found the radiator was clogged. They replaced the radiator and now everything works fine.

Colin Stickland

• 22516 Answers
• Posted on Dec 12, 2010

SOURCE: 2003 nissan sentra gxe 1.8

only one thing will cause this problem and thats the head gasket ,its pressurising ,no heat either as water is being blown out ,sorry to give the bad news

gord storey

• 477 Answers
• Posted on Dec 15, 2010

SOURCE: 2004 nissaan xterra v6 3.3L

Well , I know $800 is a big bill , but think of it this way , you got a bunch of new stuff on the car. The timing belt replacement alone would cost someone almost $800 to have done by a mechanic , and if it broke and destroyed your engine how much would that have cost. It's always nice to solve the problem on the first try , but at least it is fixed now , and you won't have to worry about any of that other stuff for a long time.

SOURCE: 2003 nissan sentra gxe I was

radiator low in water.