94' Maxima - I warm up my car and the engine shows

CHECK all the vent hoses, are they connected, no ob strucctions, when the last time you replaced the cabin air filter ? do you have one? look @ your owners manual, also, you may need to have several heater controls, or other control on as well, see owners manual, anything fall into the defroster vents ? replace thermostat @ engine. see how this works for you, good luck

Connie this sounds like your thermostat in the engine is stuck open not letting the water stay in the engine block to heat up. The fix is to replace the thermostat with a new one that will allow the water to stay in the block to warm up. The typical symptoms of a stuck open thermostat is that the air will blow somewhat warm but never hot in the winter time, but it will take a few miles for the air to warm up at all. I would check with the dealership and find out what degree thermostat to replace it with. I run a 180 degree in the summer and a 195 degree thermostat in the winter just to have hot heat in the winter. I hope this helps

For this types of problem,i suggest you to check this help links:----Car heater blowing warm, but not hot air?http://schematicsdiagram.blogspot.com/2011/12/car-heater-blowing-warm-but-not-hot-air.html
---------A/C, heater, defroster fan, not working?http://technoanswers.blogspot.in/2012/02/ac-heater-defroster-fan-not-working.html
--------Heater problem?http://technoanswers.blogspot.in/2012/02/heater-problem-on-isuzu-trooper.html
---------Engine Overheats and heater blowing cold?http://howtobyme.blogspot.com/2011/11/engine-overheats-and-heater-blowing.html
-----------Heat blows cold on drivers side and hot on passenger side?http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html----------------This will help.Thanks.

If the engine is heating properly you most likeliy have a clogged heating coil or regulator (opens to allow hot water to flow thru the heater core. No hot water to the heater cord, not heat in the vehicle. Good luck

You will have an 'in' and an 'out' hose going to the heater core. Run engine until hot, these two pipe should be both quite hot, if the out pipe feels cooler than the in pipe then it would seem the core is blocked. You say you have no leaks so maybe it would be worth removing both heater pipes, fix one side up to the water main and gently pass water through it. Hopefully lots of Brown sludge should come out.
If both pipes feel hot then the core should be ok. This means it will be an air-distribution fault and maybe the flap is stuck that changes it from hot to cold air.

Hi!
It appears we have an Air lock scenario and you will need to perform a system Bleed.
Park the vehicle on level ground, when cold remove coolant filler cap, start engine and leave to idle, turn heater on full and blower to max. When engine reaches operating temperature watch and listen near coolant filler, keep clear as gurgling and hopefully a boil over should occur. Top up with very warm coolant and wait as it may do it again.
Check for heat inside vehicle if warm replace coolant cap but keep an eye on temperature gauge as the ~Air lock may have moved on from heater matrix/core so proceedure needs to be carried out again from COLD.

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Paul 'W' U.K

did you mount the thermostat properly... sounds like it is reversed

here is a picture of the proper orientation

could be a pluged heater core back flush heater core. or heater controls aren't functioning properly

With the car warmed up,feel the heater hoses,are they both warm/hot near the firewall in the engine compartment?If they are both warm/hot,then the heater core should have circulation through it and it may be a "blend door" issue in the heater a/c assembly.If they are not warm/hot then the heater core could be dirty and plugged up and needs to be flushed.
If the above does not help,a drain and vacuum of the cooling system and vacuum refill will remove any trapped air.
Sometimes,clamping off the top rad hose and holding the engine rpm at 2000 rpm will force trapped air out of the heater core.(Watch temp gauge when trying this)
Lastly,a NEW thermostat doesn't mean its working correctly.