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-   -   Heater is blowing luke warm (https://x.nissanhelp.com/forums/altima/20955-heater-blowing-luke-warm.html)

dtalley14 12-16-2011 09:49 AM

Heater is blowing luke warm
 
I have tried doing the air from the radiator thing twice got a lot of air bubbles from doing so, but now my heat is back to luke warm and when i turn my defrost on it blows cool air. What do i do

DCARLTON 12-16-2011 12:19 PM

So you've done the procedure. When you completed the procedure, did you get hot air coming from the vents? Do you get hot air from the vents when you drive the car? What does your temp gauge show? A little less that half (and I do mean a little)? How full is the radiator? How full is the reservoir?
If you get heat when driving, but not at idle, you potentially still have air in the system. If you never received hot air out of the vents during the procedure, you might have not gotten all the air out of the system. If your radiator is not full and/or overflow reservoir doesn't contain fluid, then you might have air in your system and still getting air into the system from the reservoir. If your temperature gauge never gets to almost the half way point, then you may have a bad thermostat stuck in open (better than stuck in closed).

Lots of questions and lots of possibilities.

When you turn defrost on, it should blow cold air as it comes from the AC system, however, it also should mix with hot air off of the heater core assuming that you have the temperature setting on the hot side. I suppose it's possible that there could be an issue with a door that isn't operating correctly where it never switches to let the heat in from the heater core.

I suppose also you could have a plugged heater core. Plugged heater cores and bad thermostats on Altimas aren't a common problem but we all treat our cars differently and anything is possible.

dtalley14 12-16-2011 12:41 PM

Yes when i performed the procedure i was getting hot air from the vents and i was like whew problem solved but a couple of days later it was back to luke warm air. I have been told it could be a thermostat but it also could be that i didnt have it elevated enough when i did it as well. the antifreeze is full in the radiator

streamcast 12-17-2011 12:29 PM

I am assuming this is for the 2002 altima. If so do the engine run slightly rough on cold startup. You have air intrusion into the cooling system.
1. swollen seal on rad cap
2. aluminum crimps on rad not sealing.
3. Head gasket not sealing. May see this by removing sparl plugs, if white poss indication.
I hope this helps

DCARLTON 12-19-2011 04:25 AM

If you got warm/hot air after doing the above procedure, then you probably did it correctly. You say the radiator is full but how about the reservoir? In the past, when I've done this, I've over filled the reservoir to insure that any air in the system is replaced with coolant from the reservoir.

My suggestion would be to do the procedure again, raise the front of the car as much as you can (2 or more feet is good), do it exactly as above (or look on youtube for a video, check this link out - Altima No Heat ). Also, I remember too that if you can hear what sounds like a sloshing noise in your dash when you turn a corner, this is a good indication that there is air in the system.

In the video, this guys uses an external reservoir instead of using the Altima's reservoir. Most of us don't have these, and why make a jug as he suggests when you can use your own reservoir sitting right there at the fender.

This video is excellent on how to correct this problem

Good luck!

tonyguy 01-16-2012 03:46 PM

2005 Altima here with heater issues....
I have read the threads, performed the procedure to remove air bubbles.... no luck.

Symptoms are similar:
1. Warm to cool heated air at idle.... even with temp gauge reading 1/2 and having set off elec cooling fans... AC off.
2. With engine rpm at 2500 parked, you can not sustain holding your hand in front of the vents at max fan and max temp. Plenty of heat!!!!!
3. WHile performing the procedure and massaging the upper radiator hose and poking around under the hood, I discovered the following....

The heater hose coming from the top of the engine (at the upper radiator hose connection) is very hot (cannot hold the hose for any length of time) WHILE THE RETURN HOSE (to the lower radiator hose boss) IS ABSOLUTELY COLD, NOT EVEN WARM. (Work done while 15 F outside). The hoses have plenty of sag in them, and I raised them and squeezed them with no improvement.

It would appear that the water pump, located on the lower hose, has to pull the hot water from the top of the engine, thru the heater core, and downward to the lower engine connection and the lower radiator hose connection.

SO I am thinking (mind you I don't have a repair manual, my girlfriend's car) the water is not circulating through the core. Potential causes:
1. Kinked hoses, plugged hoses (They look good, factory original)
2. The hoses are reversed and that matters for some reason (doubtful, but don't know if there is any check valve for some reason - (passenger side connection is off the upper radiator hose)
3. The heater core is plugged up - coolant looks nice and clean, (may disconnect the heater core hoses at the block and flush with hose in the opposite direction of flow) in an attempt to test for restrictions, debris, but temp valving may interfere (see next item)
4. I don't know if this is the case... in the older vehicles, the temp control was directly connected to a mechanical valve, by a cable, which regulated the throughput of the water flow through the core... can anyone verify a flow restricting valve is used with the 2005 Altima in lieu or outside air mixing???? If so, the valve may be suspect (electric or vacuum controlled). Haven't dived under the dash yet to look for it.... any thoughts????

I need to score some points with the girlfriend, she has a remote starter, but it almost useless under the circumstances. She reports it hasn't worked in ages as best she can recall. Original owner, no major mechanical issues or body work.

Thanks in advance for the thoughtful and well crafted advice.
Tony

coreyand1 01-16-2013 11:10 AM

Help, I have the same problem. Pressure tested the system twice, shows no leaks head gasket appears to be good. Replaced radiator, bled system, replaced cap and air is still getting in coolant.

DCARLTON 01-16-2013 11:17 AM

Make sure the overflow reservoir ALWAYS has coolant in it. If it ever runs dry for any reason, air will be introduced into the system and you will eventually get no heat.

If you have bled the system correctly and all air has been removed but you still get cool air at idle and hot air when driving, you still have air in the system.

If you elevate the front of the Altima when bleeding the system (the higher the better - ramps of 1.5-2 feet are best), it insures the air seeks the higher level and escapes from the cooling system. Google search Altima and cooling system or search youtube for videos.

coreyand1 01-16-2013 11:20 AM

Thanks Dcarlton, we have done that multiple times. It seems there is a small leak somewhere even though the pressure test says otherwise. There is an antifreeze smell when the car is very warm although it appears to be coming out the vent at the top of the reservoir.

DCARLTON 01-17-2013 07:21 AM

I really hate cooling issues......

On my Maxima, I had a faulty radiator cap that would allow a fine mist when pressurized and of course the mist would be dispersed by the fans and you would never see the leak.

The little ones are the tough ones until they get bad enough that you can actually find them.

Good luck to you!

MetsFan_2112 01-30-2020 06:00 AM

We are getting this on our 2019 Nissan Rogue and it only has 4500 miles on it.


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