Ive changed out my heater core 2wice, AND bought new thermostats, 2WICE, ive had the cooling system flushed, AND got a new climate control box, ive had the core flushed 2wice and the fluid changed. Heres my problem, NO HEAT

Ive been fighting this forever, my cooling system checks out, and so does the core, the little valve for cooling works and theres no clogs,but for the life of me i cant get this thing to put out any heat. The car doesnt overheat, so im assuming the pump works. The A/C is frigid so i know that part works. Ive bled the crap out of the system and i know there arent any bubbles. Tell me someone knows what the problem is, driving in 20 something deg. weather SUX here.

Another thing, does anyone know what 3red flashes and 5 green flashes mean on the ECU?

 

Well, when i first got my Max, the heater wouldn't work. The radiator was busted, and when I replaced it, the heater worked. Sounds like that's the only thing you haven't checked...

 

i just had another radiator put in my car....the heating STILL doesnt work properly...did a reverse flush on the heater core as well as a regular flush (water flow was normal).....still nothing....changed the stat...still no improvement...the heating still works at less than half strength.

 

I think i found the problem...

After reading your post...i went outside (yeah at 1 am) and started my car....i had suffered yet again today at the hands of the virtual heating in my car....

Anyhow...the problem in my car was the fresh vent door control cable and the pivot it moves....u see that lever on your climate control that moves up and down...up for fresh air and down for closing the fresh air vent....i followed the cable down to the vent door and guess what i found!!!

the lever is moving up and down BUT the freakin' vent door is STUCK in open position!!! the small pivot that moves as a result of the main lever moving up and down wasnt even moving!! fresh (aka COLD) air was getting mixed with the heated air and messing the heating all this time.

all that money wasted on those flushes, those radiators, those coolant bleedings

...maybe the vent door pivot needs some WD40....anyhow...i hope this helps you 90Maxima!

 

there's two of those levers. One to control the fresh air vent, the other to control how much heat you want coming in(the one that slides left - right). I suspect either one could be the culprit. Just make sure the cables are clipped in place, and opens/closes the appropriate vent.

 

I had the same problem. If you open your hood there should be a valve mounted in the middle of the rear of the engine bay. This valve countrols whether you are using the heating or the air conditioning. I disconected the hoses from the valve and put them together(bypassing the valve) and now the heat works. As soon as it warms up i'm going to buy a new valve. But that might be the problem.

 

Hold the heater core hoses at the firewall, are both of them hot?

 

I had the hose that goes to the thermostat leak so I replaced it. autozone did not have the correct hose but I found a flex hose that was just a bit to big but it fit and is holding till I can get one from nissan. Now that the coolent leaked and I had to put some in it has had limited heat when I start it and let the temp come up to the middle. I fugure the temp is up I dhould have heat but nothing. If I rev it up I will get full heat. I think I have a air pocket in the heater core. I figured that when I filled it and the car wasn't running it didn't circulate through the heater core. My dad said draining it and filling it half way then starting it and filling the rest up should fix it.

 

Yes both hoses are hot, and when i flushed the core, a rushing torrent of water came out of it, so im sure the core isnt clogged

 

Yeah, when i replaced the climate box i checked those cables i dunno how many times, so i know there connected and properly attached (same as the old one) to the climate box

 

Does anyone know which hole the black pull cable connects to in the climate box? 1,2,3,or 4? I had my original one on 1, and the one i pulled was in 1. But could this be the wrong one?

 

Hey if u got a VG (dont know about the VE) there is a bleeding bolt at the top right end (looking from the grille side) of the engine....if u got an air lock....u can start the car and loosen the bleeding bolt a little bit to bleed out the air...that should save u some time and effort with replacing coolant.