Air In The Heater Core??

[Chuck1986]

Just wondering if air in the heater core finds its way out eventually (wouldn't the water pump burst the bubble eventually?)...not sure if it's there, but my heat isn't exactly "hot." For what it's worth the car is a 2001 Mitsubishi Eclipse GT (pressurized cooling system.)
Also...is there a way to see if my radiator cap is bad? (Without getting it professionally tested.)
THANKS in advance!

 

[Gary Allan]

I don't know if your engine has air purging issues or not ..usually it, after servicing, whatever is left in there gets pushed out to the coolant recovery tank. When it cools and contracts ..it draws back in liquid ..

If there's air present you'll hear it in many cases.

You won't get a pressure reading ..but just see if your hoses get firm when the engine heats up. Cold you should be able to easily squeeze the upper hose ..when it's warm ..not much give to it. You'll know that the cap holds pressure

 

[moribundman]

On some cars extensive bleeding is required to get all air out of the heater core. Check the proper bleeding procedure for your cooling system. There may be a few bleeder screws. You may also want to raise the coolant expansion tank as high as possible or attach an extension tube to the filler hole.

An air lock would surely prevent the heater from working properly. Also, check the thermostat.

 

[Trucku]

I think your pump creates enough flow to push out a bubble. if your thermostat is stuck open then besides no real heat you will see your temp gauge sitting low. Whats your temp gauge showing? You can have a clogged core. A back flush may help.

 

[1kickbuttranger]

There is also the chance the heater core is plugged and will need replacing.

 

[Chuck1986]

Thanks for the help everyone!
Seems like I need to give a little more background info:
I flushed the radiator last summer, I squeezed the upper hose until I couldn't add anymore coolant. That seemed to eliminate a lot of bubbles. So if there's any air in the system, it's cuz I didn't get it all out when I did the flush. There are also no burp screws on the car, so perhaps my best bet is to remove the radiator cap and idle the car for 10 minutes...that should purge the system eh?

The water temp gauge is perfectly in the middle, so I'm pretty sure it's not the t-stat. I can put my hand on the vents and feel hot air but it's just not the way it was last year.

 

[Ugly3]

Sure would be odd for there to be air is the system from last summer. Maybe the damper doors are not working properly.

 

[Drew99GT]

Quote:

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so perhaps my best bet is to remove the radiator cap and idle the car for 10 minutes...that should purge the system eh?

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That is a good way to get air out of the system, but be careful! If the coolant level is full right up to the fillerneck on the radiator, it will expand out and spill scolding hot coolant everywhere as it heats up when you idle it. May have to drain just a bit of coolant out before you attempt this, or be prepared for a cleanup.

 

[Trucku]

Does this vehicle have a blend door. Maybe your mixing outside air with the hot air. I know on Ford xploders they break and your either full hot(close) or cold (open).

try running a flush with a concentrated cleaner. It might help. Maybe the flush last year just stirred stuff around and clogged the heater core. I ran my flush with thermostat out so I had maximum flow rate of cleanser through system. for my truck few years old at that time, it sure had lots of debris in it.

Maybe you can use a flush kit spliced into your heating line. With the pressure of the hose back flushing core maybe you will unclog it.


Good Luck

 

[oilboy123]

If all else fails get on the road and gun it good for a while to get the pump going at full capacity.
That should do it.

Nothing like jamming it for a while to solve an air lock problem. Good luck

 

[Chris142]

Leave the cap on and run it @ 2000 rpm untill the stat opens. Then shut it down untill it cools, top it off and repeat.

 

[Trucku]

Accelerate 100mph and turn heater on. hold for 2 minutes that will clear her up.

Water is denser than the air and should have no issues pushing out of the core. There is no place in the core for air to pool. I can understand air pockets on upper parts of the engine where the water has easier places to flow to.

If ya wanna go crazy disconnect the return form core line and feed it into radiator fill and see what you get as flow. Don't forget to cap the return to pump.

How old is this vehicle? What make and model?

 

[Chuck1986]

Guys, I can't thank ya enough for the help!

Trucku - the car is a 2001 Mitsubishi Eclipse GT w/ 58k miles on it. Another thing worth mentioning is that since flushing the coolant in the summer I've put about ~2k miles on it.
I just drove on the highway w/ cruise control 80 mph (3000 RPMs) for about 45 minutes...ya think that would've gotten the air out? I'll check next time it's cold out.

 

[Big Jim]

I have experienced problems with air in the heater core. The symptom is heater core moan. The moan goes away if you clamp off one of the heater hoses so circulation is stopped. Sometimes the moan can be cured with a restrictor in the heater hose. Back in the 60s and 70s, many hars came with an "H" pipe in the heater hoses to eliminate heater core moan.

Air trappend in the heater core is not likely to make much difference in the heat output. I would be much more suspecious of either a failed thermostat or too low of a thermostat. Most cars today should have a 190 degree thermostat. The use of a colder thermostat drastically cuts heater output.