First time Nissan owner of an '06 S. We're approaching winter now and when I have the fan set at zero and the fresh air/recycled air setting set to fresh air (i.e. unlit), the heat that comes out once the engine warms up is really hot. I have not had to turn on the fan once yet. Is this just passive heat straight from the engine? That engine must be really inefficient to put out so much heat, but in winter, I'm not complaining!

Realize that until your coolant gets up to the temperature required to open the engine's thermostat, your interior heater core "is" the engine's radiator. Driven at speed, enough fresh air is being forced through the system to draw some of that hot air out onto your feet.

Engine's not necessarily inefficient. All internal combustion engines put out a lot of heat as a byproduct of combustion. I'd rather say that it has a fairly efficient heating system.

When the temp control dial is on hot, there is hot water flowing through the heater core whether the fan is spinning or not... so some heat is definitely going to drift off of it.

Engine efficiency has nothing to do with it... all modern motors warm up to approximately the same 180-200 degree mark. Maybe the X is missing some extra baffling or insulation that might keep you from feeling the radiated heat in another vehicle - but any vehicle will heat up just the same.

Because of all this lost heat, internal combustion engines, comparatively, are highly inefficient.

As a matter of fact, only 20% of the power produced is used, and pretty much the rest is lost as heat. And then consider power loss from the crank to the wheel. So 20% more out of that 20% that's usable is lost again.

There you have it.

ETA: [url= http://ffden-2.phys.uaf.edu/102spring2002_Web_projects/Z.Yates/Zach\'s%20Web%20Project%20Folder/EICE%20-%20Main.htm]More on this.[/url]

yes yes - engines are all horribly inefficient - but the point here is that Nissan's engine isn't subpar (quite the opposite)

Oh, I never contested that. I just felt like putting in my two cents, that's all.

Switching to "Recirculate" effectively shuts the vent that allows outside air to circulate in. You won't feel the heat anymore.

With the setting to recirculate, the windows will probably fog up as if two teens were shagging in the back seat.

I always leave the fan on 1 minimum or above if I need to warm or cool quicker.

I adjust the temperature with the temperature knob, but always keep air circulating with the outside. I turn on the A/C to help defrosting when the windows fog up in the winter.

The only time I use recirculate is when I drive by the pulp mill or the oil refinery. Also when cleaning the system by spraying Lysol or other desinfectant in the cab air inlet for recirc.

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Originally posted by Kaiser:
yes yes - engines are all horribly inefficient - but the point here is that Nissan's engine isn't subpar (quite the opposite) -------------------------------------------------

Ohhhhh..That explains why we get such fantastic gas mileage and tremendous horsepower

I have a 1st gen and love the car to death. Doesn't bother me that I have to fill up every other day and only have a 6 mile drive to work. Look at the heater issue as a bonus for the winter.

I was talking about the gen 2 motor.... our gen 1 motors suck.

I figured thats what you were talking about. I would have a Gen 2 if it weren't for the money issue. However I have fallen in love with the Gen 1. Really there isn't a nead for more horsepower but better gas mileage would be nice.