My heater, when parked and idle, cools down. The heater will heat again once I begin driving, but this is freezing me as I sit and wait for my kids at school. It blows cool air while I am parked and will finally start blowing warm air once I am driving again?

start with check fluid level --cooling fans operation --water pump to start

It sounds like the radiator is low on coolant.
You could also have air pockets in the cooling system if the system is not full of liquid.

Not unusual for fuel pumps to begin to fail once they are heated up from running. First thing in the morning pump is cool, then as you drive, it heats up and begins to lose pressure. After sitting a 1/2hr-1hr, it may start again and run fine for a short time and start to act up again. Had similar problem and found good fuel pressure when tank and pump cool, but lost pressure once vehicle driven a distance and pump heated up. The hotter the weather, the shorter the distance I could drive. If you can somehow set it up to have fuel pressure checked when it starts to act up, that would certainly help confirm if fuel pressure is the culprit.

Welcome to Fixya

Sounds like you have a problem with the cooling system. First thing you need to check first if the auxillary fans are working from the time you are the engine is overheating. If the auxillary fans is not working then the problem would be the aux fan itself or relays. if Fan is working then you might have a poblem with the water pump.

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Subarus can be challenging to "burp" Sometimes it takes several attempts to get the air out of the system. The procedure is simple. Top off the radiator, squeeze the hose a few times to help get the air out, replace the cap and start the car. let it idle or drive slowly near home with the heat on high. once the temp gauge begins to rise, if there is no heat get the car back to the driveway before the temp gauge gets half way. Shut the engine off wait for it to cool, at least 10 minutes. Then check the radiator again. If there is still air top off again and repeat. After 3 or 4 attempts if there is still air and or the coolant reservoir seems to be filling, try replacing the radiator cap. If this doesn't solve the problem, It may be a head gasket.

Hi, the likely problem is a bubble forming in the system, possibly due to a head gasket failure.

Try stopping on a steep incline--does the heater stay warm? If yes, what you have is an air bubble that hangs at the heater hose until pressure from the water pump blows thru it as the engine speeds up. Park on an incline, open the radiator cap, run the engine until the thermostat is open, turn the heater on, crack open any/all bleed ports to release any trapped air, and fill the radiator to the neck. Wait until the level stops dropping and make sure bubbles don't continue to come up. If they do, you may have a blown head gasket that will keep forming these bubbles until you change the gasket.

I would check to make sure that the cooling fans are capable of running. The fan's won't come on unless either the a/c is on [provided the a/c works of course] or the engine temperature has reached about 218 degrees. A quick fan test is to allow the car to idle in the driveway with both the a/c and defrost "off" and with transmission in Park. As it warms up the cooling fans should come on once the temp gauge is about 3/4 of the way up [give or take a little] If the fan's won't come on at this point then odds are you've got either a bad fan[s], blown fuse, or bad control relay. As for potential damage caused from the overheating: the most common problem I see is head gasket leaks that allow some of the combustion gasses to get into the cooling system which disrupts the coolant flow and causes it to overheat again from this new problem. A common symptom of a head gasket leak is an engine that will suddenly run hot [but the heater stops blowing hot air when this is happening] then the engine will again run cool nearly as quickly for a while before repeating the cycle. If the leak is big enough it will often force coolant out of the reserve tank when this is happening. If it's been driven for some time and hasn't overheated she may have gotten lucky and avoided any damage. Hope this helps a bit!

Hya!
You need to bleed the cooling system.
To do this park on level ground, when cold remove coolant filler cap, start engine and leave to idle.
Have plenty of warm/hot water available, when engine reaches operating temp it may appear to boil over so keep away from coolant filler, top up with warm/hot water and wait as it may bubble over a few times before settling.
Replace cap and hopefully back to normal, Remember your Anti Freeze?
Good luck,
Paul 'W'
Oner~EDson(:0) {#><U.K.

The humming is the noise the coolant makes when the car overheats and forces open the relief valve in the radiator cap and flows through the small hose to the recovery bottle., it you had all this work this done only 2 things can cause the issue, one is a problem with the cooling fan, the other is a blown head gasket, which I suspect is the problem, before you flushed the system was the coolant rusted?

first thing to do is make sure yo have enough anti freeze in the radiator, once yo know yo have that you can drive the car.

secondly the problem could be a bad radiator fan motor which does not come on when it is supossed to, as long as the wind is blowing against the radiator it will not over heat so again check the radiatro fan motor and the fan relay.