wrj

Some times I just want to pull in outside air without having to run the A/C. But the air coming in is definitely hotter than outside air. I wonder if the outside air duct is also sucking in hot engine compartment air. Does anyone have this same problem? Any fixes?

MaxMaybe

This has been discussed ad infitum and is a known Nissan design flaw.

I just bought an '04 Toyota Sienna MiniVan and when you set it for UNTREATED outside air, that's what you get.

Do a search for this topic; there should be plenty of posts.

bluemaxx

Try this:

Select Auto, 60 degrees, outside air, off.

CanadianMoFo

Well yeah that will work since the A/C will be on.

I think he was wondering why the air gets heated on its way through the ducts even when the temperature is turned all the way down. A common Maxima issue.

Often the temperature outside is lower than what I want on the inside. I should be able to get cold outside air, without running the A/C, so I get fresh air and better fuel economy.

CM.


EDIT: bluemaxx

Oops! I clicked edit when I should have clicked reply...

bluemaxx

The A/C won't run if the system is set to off. The key for me seems to be setting the temp to 60 and outside air before switching it off.

CanadianMoFo

Oops sorry...missed the "off" part.

I'd just like to be able to bring in outside air without heating it. Leaving the temp all the way down and the fan on the first or second setting.

Mike_TX

You know, this is referred to as a "design flaw" both here and in the G35 forum (and in the Acura forum, as well, btw), but let's look at it:

Ductwork for the air intake has to be somewhere, ok? So it makes sense to have it on or near the firewall, next to where the blower motor is located, and where the air can come into the passenger compartment.

Problem is, the engine makes a lot of heat, and especially when the car is moving, that heat flows right back at the firewall, which in turn heats up the ductwork. Heated ductwork = heated air coming through it. Hmmmm. So maybe we move the ductwork to the front of the car, up in front of the radiator, to get it out of the way. But ... hmmm, now how do we get the air back to the passengers in the cabin? Darn, I guess we have to run it through that pesky engine compartment, don't we? And it's gonna heat up because of engine heat.

Well, maybe the ductwork should be insulated with some kind of space-age insulation that will keep the air inside it cool while the outsides of the ducts are hot. Nice idea, but there are limits to that, unless you don't mind bulk and expense. Turning the ducts into the equivalent of thermos bottles just isn't practical.

Maybe the answer is to develop an engine that doesn't make any heat. (Just kidding. )

The point is that this isn't a design flaw ... it's a reality that all automakers face. Every car I can recall ever owning did this, all the way back to my first car, a '53 Ford Victoria. Only then, I didn't have A/C. But we do have A/C now, and to overcome this problem, use it! Air conditioning in 2004 draws so little energy from your drivetrain that gas mileage is virtually the same with or without it.

If nothing else, use the A/C long enough to cool down the ductwork, then switch it off. Me? I ain't gonna switch mine off ... I run it year-round. Thank God for air conditioning.

Mike

tubells

Mike's right ... the air has to come in from over the engine and is always going to be hot.... had the same problem with my 626 as well. It s even more noted when the intake vents are covered by the hood as compared to older model cars that had them on the outside

just remember, when you use outside air (with no ac) try and keep a window slightly open for the cross vent.. {not sure if this is the right term (use the moon roof for least noise)}

MaxMaybe

These are all valid points regarding the ductwork.

However, I refute the notion that it is like this on all cars. I have been driving since 1965 and after going thru the list of at least 24 vehicles that I have owned or driven regularly, only three of them had trouble giving me ambient outside air temperature through the vent systems and the ‘04 Max is the worst. I have also read that this is a common trait of Nissan vehicles in general.

Anybody remember the cars in the 60's where you could reach down under the steering wheel and open a vent for an extra fresh-air intake? On summer nights it was like having air conditioning! We used to call it the “Crotch Cooler.” (Actually, we used another part of the anatomy, but I won’t mention it here.)

As automobile HVAC systems get more complicated and engine bay compartments get hotter, it’s probably more difficult to get air inside the cockpit without it being heated.

However, my wife’s former ‘97 & ‘02 Outbacks and now ‘04 Toyota Sienna are able to bring in ambient outside temperature merely by setting the temperature control to the desired setting and turning the AC off (as long as it's not lower than the outside temp, obviously.)

It is virtually impossible to do that on an ‘04 Max even going thru BLUEMAXX’s routine which I agree is the only workaround. But, that air will still be heated to some degree.

It just bugs me and is a waste of energy that Nissan forces you to turn that AC compressor on to get cool air into the cockpit sooner than you should have to. If Toyota and Subaru can, why not Nissan?

maxamer

I am a 4th gen owner and it, along with every car i've owned previously, allows the outside air in via the ducts without heating it up.

For those familiar with the 4th gen HVAC controls, one simply turns the system off, then presses the 'MODE' button to select which vents you want open, the outside air starts flowing in (the car has to be moving of course). Depending on how long the car has been sitting outside, the air temp coming from vents soon matches ambient air temperature.

I am not sure why bringing in outside air without heating it up is such a technical challenge? Almost every car has a fresh air setting: turn the fan off, move the temp control to the coldest setting, and I guarantee that if you drive on a cool nite the air coming through the vents will be as cool as the outside nite air.

wrj

bluemaxx is right... I experimented today with the approach of setting the Auto controls to 60deg then turn it off. Now everything is off. Then turn the fan on (using the Fan switch and you may have to use Mode to get the air to come out the top vents). The A/C will turn itself back on so you will have to switch the A/C off (using the A/C button...not Off). The air coming in through the vents was definently cooler (it was 60deg outside). The display indicated the A/C was off. I then tried the experiment again at other temps. It appears (and I mean appears since I didn't do a lot of testing) that there is a design flaw. You don't have to set the Auto to 60deg either. Just below 70deg. I tried 73deg and 75deg and it starting heating the intake air.

Also, there is a post on G35 forum. They have found that the fresh air duct has openings into the engine compartment. Several have used silicone to block the gaps in the ductwork to help the situation.

greg_atlanta

A/C is broken on my Q45 and the vented air at 65 deg is quite pleasant for about 10 mins when the engine is cold (parked in the shade). After that, forget about pleasant..... that's what windows are for.

CanadianMoFo

Its not a matter of not setting the controls right. The damn car brings in pre-heated air from the engine compartment by default. I turn off the HVAC so there is nothing operating and there is hot air blowing in at my feet.

CM.

maximage

My T100 has its fresh air intakes on top, behind the hood but before the windshield (under the cowel).

There is a dead spot here- the air stream up the hood actually flows over this area, creating a wash. That is a design problem. The air can be ducted in from the sides, behind each wheel, or an intake scooped from the quarter panel. Older Landcruisers used to have a pop-out vent that literally, popped open to the outside...(I could see tree tops while going up Pikes Peak).

So, true, the engine heat can increase the temperature of the incomimg air. But, design and location of the air is more important. I think they considered that with A/C units being more efficient than previous units, running the A/C will not be a fuel-consuming as one thinks.

What I will compliment Nissan and Toyota on is that you can turn the A/C on with a button. Some domestics don't allow this (Ford..) as its either A/C or MAX A/C. I tend to need the de-humidifiying feature (Here in the East) with the A/C on and defrosted vents selected. And it works well in the winter (defogging). I am just amazed at how much cooler the Nissan gets over my Toyota.

(One could always get some ducting and cut a hole...)

kmoney56

Whatever the reason for this problem, the thing that works for me in this car (and my last) is switching from fresh air to recirculate. This is the only setting you can change with the system off for a reason. Try it. No air comes in through the vents, hot or cold.

maxamer

Now that would be damn annoying...!

NismoMax80

iTrader: (6)

that was weird, had outside air on, 60 deg, fan/ac off and nothing. popped up moonroof... air flowing in vents!!! As long as car is moving, and not hot outside, it's kinda cool and blowing in. (funny: roof cracked-air, closed-no air)

Considering how effecient the AC has become, and how it is required to dehumidify/defog, I'll use it more than I used to.

Anyone know how the heated mirrors work? Do they activated with the defrost?

jc53

The mirror defrost activates with the front window defrost if my memory serves me correctly.

However is it normal that the A/C automatically goes on when you turn on the defrost? Mine does, regardless of temperature.

bluemaxx

Mirrors are switched with the rear defrosters.

Yes it is normal and desirable for the A/C to be on with the front defroster. The A/C cycles to remove humidity from the cabin.