Every day, I drive the Z across town to pick up my wife, maybe 5 minutes.
In that time, the car warms up and I get heat.

When I stop to wait for her, the heat gradually turns cold. If I idle more than a few minutes, it's like the a/c is on.

After we resume driving home, the heat returns. Is this an a/c controller bug or some sort of thermostat thing?

thanks

 

something's definitely wrong with your heater. i'd take it in for service.

 

yeah, mine does this too.. keep driving it for a while.. and it won't do it. i thought about taking it in but im just damn lazy and not a whale's vagina

 

Yeah my 05 Altima does the same thing. subscribing. Hopefully somebody's got the answer.

 

uhhhhhh yeah take it to the Dealer, thats not normal.

 

Sounds like Heater coil. Happened on my Ford ranger and My G'mas Taurus too.

 

In COLD weather, many times the heat will only work when the engine is at a certain temp. which is achieved by it being under a load (driving) At idle the thermostat closes and u loose water temp. ( the opposite is true in hi summer temps)If at idle u bring ur RPMs up for a couple minutes and the heat returns, that is the prob. Nissan offers no therms. to compensate to my knowledge.

Point is-- ur water is not hot enough to compensate for the fan blowing over the Heater coil---Which is really a radiator.

NOW ---U may have a prob with the climate control. That u would have to take it to the dealer for or preferably a really good A/C-Heating specialist if ur not under warrenty

 

Mine was doing the same thing until I got a radiator flush and fill.

 

+1 No load + fan + cold = insufficient load for the bypass to the heater core to open. The car keeps the heater core bypass closed to keep the engine warm and to allow it to warm up the engine to the proper operating temperature faster.

 

Some good points, although I would like to add the following:

The heat returns IMMEDIATELY as soon as we resume driving.

Also, last Friday, the heat even cut out at a stoplight (What's that, 60 seconds?) and resumed when we began to move again. Freaky.
Every other car I've owned has supplied heat to the interior unde idle.
Car's already warm, right? 8 minutes of stop + go driving to get across town + I'm south of Atlanta, so our cold weather is above freezing (35 - 50 degrees)

Actually, now that I think of it, I have this problem up to 65 degrees, which is why I initially thought it to be a computer control problem. When it started happening, I used to try the "Microsoft technique", turning the auto climate off/on. Later I found even set to 97 degrees heat only, I would still get cold air. Maybe a vaccuum line leaking, can't hold the ventilation levers at idle?

 

Mine does the same thing too. The heat only comes on after driving 1-2 miles. I guess the AC/HEAT really sucks on Nissan Vehicles .

 

Well ---the vacuum comment was valid --and there are situations that I have had to repair sluggish vacuum motors ( the mechanisms that open and close the HVAC doors) by replacing bad hoses.Or even introducing some oil to the hose to be pulled into the motor to relube and seal.

But at idle ur vacuum is at its max, so that kinda rules that out.

I can remember yrs ago when I was in the Hyway striping business, after driving coast to coast in Southern Fla. trying to find a motel, we finally said fuc it and pulled the trucks over. I was in a GMC 6500 Series cab over that I left running cuz it was freezin out-----No heat----Til I bumped up the idle a few hundred RPMS

 

The engine/radiator thermostat doesn't bypass the heater core so if it were to remain closed, you would still have whatever heat was available. Also, the hot/cold air mix doors are controlled by electric motors not vacuum. You probably have air trapped in your cooling system for whatever reason. Check the coolant levels in your radiator and reservoir tank. There is also an air bleed in one of the heater hoses. This can be opened to release trapped air while adding coolant to the radiator.

 

I posted on this awhile ago when the temps started getting colder outside. My issue was attributed to just a slightly low amount of coolant. Once I added a little more and made sure it was at the "min" level, the heater started working fine again.

 

What kind of coolant did you use? Can you just get a regular " GREEN " one at Auto Zone or do you have to get the one from Nissan?

 

Worked for me too...funny thing was the expansion tank was only about 0.5" below the min linr.

 

I paid $18 for a gallon of Nissan coolant. Something about "silicates".

Why take a chance? All I needed was about a cupful. Still waiting on another cold day to test it out.

 

I had the same problem with my Z a couple years ago. It turns out I was a little low on coolant. That was the first problem, after filling with more coolant I still had the same problem. I found out that I had an air bubble in one of the coolant hoses. Basically when the engine is not hot, you take off the fill cap for the coolant and squeeze the hose that runs to the radiator. Mine had an air bubble in that hose. After that no problems what so ever. Might not be a guaranteed fix, but worked in my case.

 

Having the same problem. I will try adding coolant also and get back with you guys. This started happening ever since I dropped the CR in the car to 8.5. I noticed my coolant was not at the high level but at about midway. I will top it off and hope it works. I get the same exact issue, stopping at a light and about 20 seconds go by and it feels like someone put the thermostat down to 65.

 

Mine too!! thought i was going nuts, lol. after about 15 minutes driving it will stay warm when i come to stop light, but before that it will get real cold whenever i come to a halt. gonna check the fluid level thing also.