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Bottom vent always blowing hot air


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rafale_05
User

Oct 4, 2013, 2:00 PM

Post #1 of 11 (1540 views)
Bottom vent always blowing hot air Sign In

I have a 2007 Altima 2.5S, and I have a weird problem I've never seen before.

When I have both bottom and top vents open, the bottom vent only seems to blow hot air while the top one blows cool air from outside of the car (this is with the AC off and fan on). The AC still works, and so do the flaps that shut off the airflow to the vents. The car does not have climate control.

Does anyone know what the malfunctioning part is? What's the usual time and cost to replace this if done at a dealership?


(This post was edited by rafale_05 on Oct 4, 2013, 2:10 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 4, 2013, 4:03 PM

Post #2 of 11 (1522 views)
Re: Bottom vent always blowing hot air Sign In

Tad confused but a maybe is if coolant level is low heat only makes it to lower vents. Would check it anyway. Must be full in the whole system not just the recovery tank,

T

(edit out typos and my own confusion)



(This post was edited by Tom Greenleaf on Oct 4, 2013, 10:40 PM)


Discretesignals
Ultimate Carjunky / Moderator
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Oct 4, 2013, 5:00 PM

Post #3 of 11 (1516 views)
Re: Bottom vent always blowing hot air Sign In

I'm confused. You stated "with the ac off" and then later you stated " The car does not have climate control"


Which is it? Does this car have manual climate control or automatic climate control?

When you state "top and bottom" do you mean defrosters and floor vents?





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Oct 4, 2013, 5:01 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 4, 2013, 10:54 PM

Post #4 of 11 (1502 views)
Re: Bottom vent always blowing hot air Sign In

rafale, DS, I think I confused it more and just changed my post some. Said in there is that the A/C whatever type works fine and I take it that heated air isn't even out of top vents (panel or defrost) versus the floor vents. If so it probably isn't a dash control issue but rather the heater core is not even in delivering heat such as low on coolant COULD possibly do.

rafale: If this car doesn't use a radiator cap for access it's harder to know system is truly full. Feel heater hoses going into firewall. Cool engine squeeze upper radiator hose and listen for gurgles. Careful as things are hot.

The real problem if coolant level is in fact low is WHY is it low? With that there's no guessing on what is wrong yet or how much it could cost,

T



rafale_05
User

Oct 5, 2013, 1:33 AM

Post #5 of 11 (1496 views)
Re: Bottom vent always blowing hot air Sign In

Apologies for the confusion original post. Let me clarify.

During the fall season we get sunlight that makes the cabin hot, but the air outside is cool. In order to keep the inside of the car cool without having to open the windows, I just crank the temperature knob all the way to the cold side and turn off both the AC and recirc. This just brings unheated/uncooled fresh air from the outside.

What's happening now is that whenever I do this, the air coming out of the bottom vent is heated when it should really be at outside temp.


(This post was edited by rafale_05 on Oct 5, 2013, 1:35 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 5, 2013, 3:17 AM

Post #6 of 11 (1485 views)
Re: Bottom vent always blowing hot air Sign In

OK - Now that seems more like a blend door issue. Exactly what could be hard to know exactly without observing the actuator if at all possible without taking things apart.

This is somewhat inconsistent with the A/C working properly as heater could easily overcome A/C if requested at the same time by failure heat would win. Now without an X-ray of the operation I think you can get recirculated A/C to work but when fresh air is requested it's not fully bypassing the heater core.

This could be a pest to isolate the exact cause,

T



rafale_05
User

Oct 5, 2013, 12:58 PM

Post #7 of 11 (1476 views)
Re: Bottom vent always blowing hot air Sign In

You're right about the heater overcoming the AC. When I turn the AC on, the air coming out of the bottom vent turns from hot to warm, but not cold as the air coming from the top vents. What I meant by the AC working fine is that the compressor unit itself did not seem to be malfunctioning.

So I guess you're right about this being a blend door issue. How much would this cost to get fixed at a dealership?


(This post was edited by rafale_05 on Oct 5, 2013, 12:59 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 5, 2013, 3:39 PM

Post #8 of 11 (1469 views)
Re: Bottom vent always blowing hot air Sign In

I can only educated guess at what area could be wrong to cause this so how much is impossible and can't even be sure it isn't some other who knows why reason without checking it out in person then find out just what is needed.

Dash work is almost always labor intensive vs a part -- that if it's not something else altogether. So, to know it could even take some time hands on checking things out.

Don't tell a shop what you think is the problem/cause but rather ask them for an estimate with the symptoms you are having and let them diagnose it as they are right there of course.

Best I can say is I don't hear of this being common to your car. Might be but exactly what you are describing isn't common or already at this site TMK.

Let them look and let us know what fixed it. Good luck,

T



rafale_05
User

Oct 5, 2013, 4:40 PM

Post #9 of 11 (1464 views)
Re: Bottom vent always blowing hot air Sign In

Will do. Thanks for the advice guys.

My first feeling was that it's some sort of an actuator malfunction somewhere, but I'll let the dealership find out. I know they're going to shank me on labor, but it can't be helped.


(This post was edited by rafale_05 on Oct 5, 2013, 4:40 PM)


rafale_05
User

Oct 7, 2013, 5:28 AM

Post #10 of 11 (1443 views)
Re: Bottom vent always blowing hot air Sign In

Update: Drove the car again for the first time since I discovered the issue, and the problem seems to have resolved itself. Weird.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 7, 2013, 6:36 AM

Post #11 of 11 (1438 views)
Re: Bottom vent always blowing hot air Sign In

Good and bad. If a blend door just stuck and freed up it might be all over and forget it for now. Actuators that fail sometimes strip gears and that wouldn't heal.

Either way if it refuses to act up now finding what it was would be a waste right now IMO,

T







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