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Not enough heat out of the vents - how can I fix this?

16359 Views 29 Replies 6 Participants Last post by  internetautomart
It's getting cold where I'm at and I just noticed that the Maxima isn't really pumping out the heat like how I'd expect it to (first winter with it). Is there anyway to increase the heat blowing out of the vents? Would putting a piece of cardboard in front of the radiator help this at all?
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Your thermostat is likely bad. It happened to me several years ago.

It's fairly cheap and not too difficult to replace by yourself.
Well that's good news! Where is it located? What tools do I need to change it?
Your thermostat is likely bad. It happened to me several years ago.

It's fairly cheap and not too difficult to replace by yourself.
not likely at all.
there is probably air in the system, you need to bleed ALL the air out of the coolant system (takes a while depending on what method you use) and then you will get heat back.
Okay, bleeding air out of the system - that's something new to me!

How do I do this bleeding without destroying the heat system altogether? There is still moderate to low heat coming out the vents and the outside temperature keeps getting colder.

Thanks for your help.
First, check your coolant level to make sure it's not low. You can do so by looking at the plastic expansion (overflow) tank and by opening the radiator cap (when cold) and taking a peek inside the radiator.

Also remove the air bleeder bolt when you remove the radiator cap.

See the bolt that is on the top on the intake manifold in the pic (look towards the lower right near a bunch of hose connections)? It's the small bolt next to the sticker that reads NEVER OPEN WHEN HOT. That is your air bleeder bolt.

If you are low, then add coolant/water mix with both the radiator & the bleeder open. After it's full, close them. Also, make sure the expansion tank is up to the MAX line with coolant/water mix as well.

Run the engine at 2000 RPM for a minute or two. Turn the heater on as well. Shut off. Make sure radiator is cool, then check the coolant level again. Add coolant/water mix if necessary. Run the engine again, heater on, shut off, make sure it's cool, then check again...

I've opened up the cooling system on this car several times, and this is all that was required to get the air out. When I had air in the system, I could actually hear the water flowing into the heater core from inside the car.

Drive it and see how your heat is. If you still don't have much heat, it is most likely the thermostat.

When my thermostat started to go, the engine still warmed up eventually but it took a long time to for the TEMP Gauge needle to reach the middle of the Gauge.

Also, if I went down a long hill, the TEMP gauge would actually go down towards C.

To replace the thermostat, go to this link for instructions. | Vehicle Selection - Year

Here is where the thermostat is located.

You can buy thermostats from most auto parts stores or from Nissan.

I bought mine from Nissan and there are two types that were available. 76 C and 82 C. The numbers reference temperature in Celsius.

You want the 82 C thermostat as that what the car has in it from the factory and you'll get more heat.

Even on cold days, my car usually warms up in the first mile or so on the way to work.
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Your are awesome!! Thanks for your help. I'm going to try this tomorrow. Just to make sure, I attached a pic with a red arrow pointing at what I think the bleeder is. Do I have to take it right out or just loosen it?

I'm excited to see if this works!!! BTW, what are the other circles for?

I've had a few problems with the heater. It's also blowing in a hellish smell when it just idling. At first I thought it was exhaust (which it might be), but then I though it could be power steering fluid! Is this possible? My power steer has been groaning lately when turning. Where is the hole in the firewall located? My gf has the car right now and I can't check. The smell is immediate when starting.

Thanks again for you help. I'm just praying it works.
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The red arrow is indeed pointing at the bleeder. Take it completely off. It's not a very long bolt.

If you want to confirm if the smell is from the power steering, take the cap (also a dipstick) off the power steering fluid reservoir and smell inside. Does it smell like the hellish smell? Check the fluid level and condition on the dipstick while you're at it.

Your firewall is pretty well sealed. Everything that goes through it has at least a grommet around it.
do you have enough coolant in your motor?
Well, I did the bleeding of the system twice. I popped the hood, took out the bleeder, checked the rad, topped up the reservoir. Then I put the bleeder back in. Started the car and turned the heat on for about 2 mins. Then I checked the rad again. It seemed to have more fluid in it than before I started it. Then I repeated the latter steps again.

I'm not sure if it got the heat to as hot as my Pathfinder, but it does get warm. If I turn it up to 32C on my autoclimate control tho, it's not scolding hot like I think it should be. Should I perform further bleedings? Was I supposed to run the car/heater with the bleeder removed?

Now my big problem in the horrible smell that I get when I start it in the morning. I've just been using the 'recirc' option to keep the smell from getting. It's really annoying, even more annoying than the heat problems. I wish I could send the smell over the internet so you could me what it is. I popped the hood and just using my nose, it smelled like it was coming from the front left side of the compartment. Any ideas?
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Look for drips on the ground under your car after it has been parked overnight.
(it may help to place a piece of cardboard under your car) if you cant find anything try
checking your cabin filter for nasty smelly crap. sorry if that doesn't help, just adding my 2 cents.
Okay guys,

Seeing as the bleeding didn't help, I'm going to replace the thermostat. Could someone give me some tips on how to do this properly? Should the car be cold? Any help would be appreciated.
how long did you bleed it?
HOW did you bleed it?

as an aside, do you know how to remove the steering wheel on your pathfinder and your max? if you do, could you see if they use the same electrical connections for the horn and cruise control?
I bled it according to Tom200's instructions (above) - so about 5-6mins . I have never done it before so I used his instructions the best I could. Is there a better way that you know of? If so, tell me how - I don't want to change the thermostat for no reason!
the BEST way (and the factory recommended way) is to jack the front end of the car 3 ft in the air (rear end still on the ground) with the radiator cap off and let the car run to burp out all the air. it will most likely take quite a while for it to all happen. Bleeding my VEs took 30+ minutes.
Really!??? So the car is running with the rad cap off, for a half hour? Won't coolant go everywhere? What about the bleeder screw? How do you know when it is done?
as long as the cap is off when you start then you will be fine. just keep looking at the level and adding as necessary. you know you are done when heat comes out the vents and you don't need to add anymore coolant.
Okay, great! Thanks for your help.

Could I park on a steep hill and do this if I don't have a jack? 3 feet seems pretty high, especially with a couple feet of snow on the ground. Do I just leave the bleeder "as is" or do I remove it too?
Oh, two more questions......Do I just let the car sit there idling, or should I rev the engine? Do I turn the 'AUTO' mode on the climate control 'on' the whole time? At a particular heat? I want to do it right.
It's getting cold where I'm at and I just noticed that the Maxima isn't really pumping out the heat like how I'd expect it to (first winter with it). Is there anyway to increase the heat blowing out of the vents? Would putting a piece of cardboard in front of the radiator help this at all?
I know its maybe too late, but what I found out with my sentra is that it has air in the cooling system. Now here the fun part, the reason it has air in the system is because I have a blown head gasket, if after bleeding the air and you get air back in the cooling system most likely its a bad head gasket.
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