Got air in your heater core? Need help getting rid of it?

[BlazerLT]

I recently have had the gurgling water noise under the dash and I again replaced my rad cap that for some reason failed again but I still was not getting the air out of the core.

You want to know how to get rid of it, here is the trick.

Have the front of the truck and radiator higher than the heater by using ramps or parking it on a steep hill. This will have the air being forced to the top spot it in the cooling system which is the rad now. Make sure that you have the rad cap side slightly higher as the rest of the rad as well. This will have you getting rid more of the air.

1.) Turn the heat to full and the directional controls to panel or floor. Turn the fan to medium speed.

2.) With a cold engine only, remove the rad cap, start the engine and hold the engine revs at 1500-2000rpms until the engine warms up and the thermostat opens. You will see the coolant quickly drop when the thermostat opens. This is the time to start adding your 50/50 mix of dexcool and distilled water. Add until it is right up to the top and you will see the air bubbles coming up as the coolant displaces the air in the heater core. Continue this for about 10 minutes or until no more air bubbles is coming out. Don't worry if small amounts of coolant is coming out of the rad fill neck, you want that.

When no more air bubbles are being seen or the coolant level is not dropping anymore, install a new stant rad cap and drop the engine back down to idle.

Now, be patient, there might be a little more air in the system for another day or two by right after doing this, take the truck for a god 50 mile run to make sure the coolant is getting everywhere it should be.

since I did this, nothing but slosh-free driving.

Enjoy guys!

[twiztedI8]

what will air in the heater core do?

[wolfox]

Air in the heater core will allow partial evaporation of water out of the coolant. Over time, this very corrosive, concentrated coolant will eat its way through the aluminum where there is no solid stream of coolant flowing and perforate the heater core. Keeping your system topped up and air-free keeps you from having blown out heater cores or eaten out and leaky top passages in your radiator too. Keep the system totally topped up and air free as much as possible.

[JoulesWinfield]

Great topic.
I had no idea this would happen.

Mine just started the gurgling recently.

Guess its off to the local auto parts store for a cap and some coolant.

Lt, do you think one drive on ramp on the passenger side would be high enough?

[BlazerLT]

Originally Posted by wolfox

Air in the heater core will allow partial evaporation of water out of the coolant. Over time, this very corrosive, concentrated coolant will eat its way through the aluminum where there is no solid stream of coolant flowing and perforate the heater core. Keeping your system topped up and air-free keeps you from having blown out heater cores or eaten out and leaky top passages in your radiator too. Keep the system totally topped up and air free as much as possible.

Actually, it is not the concentrated coolant that eats heater cores, it is the acid formed when Dexcool is exposed to oxygen and heat that does the eating.

[blazee]

Most heater core failures are a result of electrolysis. These leak due to pin holes caused by electricity flowing through the cooling system to ground. There are two main causes of electrolysis..... faulty engine grounds, and non-maintained coolant getting acidic causing it to become ionized and produce voltage. (like a battery.)

You can test your system with a voltmeter, place the positive lead in the coolant and the negative lead on the negative post of the battery. Any reading above .3v can cause heater core failure.

Essentially wolfox and BlazerLT are both correct.... Dexcool uses OAT (Organic Acid Technology). Higher concentrations of dexcool means higher concentrations of acid. The higher concentrations of acid cause the coolant to become ionized and "eat" or "burn" through the core.

All the above would also apply to other parts of the system, such as the radiator.

[JoulesWinfield]

So what if I dont use the infamous Dexcool and I just use regular antifreeze?

Is there still the same potential for disaster?

[BlazerLT]

Originally Posted by JoulesWinfield

So what if I dont use the infamous Dexcool and I just use regular antifreeze?

Is there still the same potential for disaster?

Yes, if you mix them, you will make a hideous brown sludge that will essentially clog your whole cooling system.

[dmbrisket 51]

great topic lt, very simple and kinda 'obveous' but then again no one thinks of it... and seince joules brought this up, if your system is designed for dex cool use it, it has a different base designed not to eat at that rubberband/plastic intake gasket you have, coolent is not just coolent, keep it green if its a green system, keep it dex if its a dex system

[xjcamaro89]

Would there be a real big problem with replacing the dexcool with the green stuff, i replaced the dexcool with the green stuff in my current 2000 blazer because the dexcool destroyed my well maintained 97 blazer in April, so when I got my 2000 blazer in april i immeditly flushed the system and replaced the dexcool with the green stuff and have not seen or heard any noises or tell tale signs of the crappy dexcool anti freeze, after doing a intake gasket job on my 97, I saw that all of the coolant ports going from the head to the intake were almost completely clogged, with the brown sludge, and I kept my 97 very well maintained and the dexcool still destoyed it, so i went with the green stuff, and havent seen or heard a problem since, but my question would be, what harmful effects does the green stuff have, let me rephrase, what "legitamate" effects will it have, i want to know proven problem, not what some will "think" might happen, thanks again!

[deadeye]

Ummm, how do I keep the engine at 1500-2000rpms and watch the coolant level at the same time?

[ChrisGood]

you manually open the throttle under the hood. On my 00 jimmy there are 2 cables running up by the intake, the one on the right is the throttle

[BlazerLT]

Originally Posted by ChrisGood

you manually open the throttle under the hood. On my 00 jimmy there are 2 cables running up by the intake, the one on the right is the throttle

No, you can't do that seeing you will need both hands and you will need to hold it open for 10-15 minutes sometimes.

I suggest a piece of wood under the gas pedal to keep it open and constant.

[dmbrisket 51]

Originally Posted by xjcamaro89

Would there be a real big problem with replacing the dexcool with the green stuff, i replaced the dexcool with the green stuff in my current 2000 blazer because the dexcool destroyed my well maintained 97 blazer in April, so when I got my 2000 blazer in april i immeditly flushed the system and replaced the dexcool with the green stuff and have not seen or heard any noises or tell tale signs of the crappy dexcool anti freeze, after doing a intake gasket job on my 97, I saw that all of the coolant ports going from the head to the intake were almost completely clogged, with the brown sludge, and I kept my 97 very well maintained and the dexcool still destoyed it, so i went with the green stuff, and havent seen or heard a problem since, but my question would be, what harmful effects does the green stuff have, let me rephrase, what "legitamate" effects will it have, i want to know proven problem, not what some will "think" might happen, thanks again!

ok, as i said in post number 9 i beleve, the green stuff has a different base from the Dex cool, the green likes to eat away at that plastic rubber intake gasket, and you will eat through the seal with green... and to get brown sludge in a Dex system, your 97 was not taken well care of, Dex cool sludges up when it is mixed with oxygen and exposed to heat (will do it in just oxy. but the heat speeds the process up) keep a good rad. cap (factory ones are shitty) on the dex cool and keep it toped off and you will have no problems with it

[BlazerLT]

Originally Posted by dmbrisket 51

ok, as i said in post number 9 i beleve, the green stuff has a different base from the Dex cool, the green likes to eat away at that plastic rubber intake gasket, and you will eat through the seal with green... and to get brown sludge in a Dex system, your 97 was not taken well care of, Dex cool sludges up when it is mixed with oxygen and exposed to heat (will do it in just oxy. but the heat speeds the process up) keep a good rad. cap (factory ones are shitty) on the dex cool and keep it toped off and you will have no problems with it

Perfectly said.