Air in the cooling system. "SOLVED"

BADs Crew · Post by **BADs Crew** » Sun Oct 30, 2005 3:17 pm

I usually warm my truck up for 15 minutes before going anywhere. Yesterday I had to get in and go because we where leaving the Blazer at the shop. When I turned out of my driveway I heard a gergling noise under the dash like water bubbling through the heater core. It did it again today when I ran out without warming up so on my way back I drove rite to the local Auto Zone and open the hood to check the level of the antifreeze thinking it may be low. I didn't open the cap but looked in the over flow tank and it was half full. I swear it sounded like air in the system. Any ideas? I did change the cap a few months ago after reading about the problems with the GM stuff.

Post by **HenryJ** » Sun Oct 30, 2005 3:40 pm

Are you running Dex? You do have the correct type of return valve, right? You need the spring-center one.

To purge the air. If you don't now have a "lever type" radiator cap, take the cap off while cool. Fill to the top with coolant. Place your palm over the top and use your right hand to squeeze the upper radiator hose. This will purge the air to the expansion tank.
Replace the cap and run to operating temperature , this should purge the remaining air that has been trapped. When it cools it should draw back in coolant if your cap is working properly.

BADs Crew · Post by **BADs Crew** » Sun Oct 30, 2005 4:03 pm

Yes that is the thread that made me change my cap. It is the center spring and I just went outside and did the hose thing. I heard that noise about a month ago but thought it was rain water in the cowl. I never hear it when the truck is warmed up before driving. I'm a nut for warming both of the trucks up in the morning and cleaning the outside of all the windows. I hate dirty glass.

Post by **HenryJ** » Sun Oct 30, 2005 4:26 pm

Are you running dex?

BADs Crew · Post by **BADs Crew** » Sun Oct 30, 2005 5:58 pm

Yes. The shop I use doesn't have a power flushing machine to do the cooling system. I was afraid to just dump it and flush it myself, It seams to be stable so I was going to leave it for now. That heater core swap I saw scares me though.

Post by **HenryJ** » Sun Oct 30, 2005 6:18 pm

BADs Crew wrote:... I was going to leave it for now. That heater core swap I saw scares me though.

If it is the original Dex, change it now. You are past due.

Don't forget the two things that contaminate Dex...air, and heat. You have air in the system, so you need to flush and replace the coolant.

I am not going to preach the removal of Dex. There is plenty of information around to make up your own mind. If you do keep the Dex you do need to monitor it closely for warning signs.

When Dex goes bad you see dirty crystals forming around areas where it contacts the air. The fluid appears slightly "milky" or opaque. Good Dex should be a vibrant clear orangish color. I hate to say it but the death gurgle in the heater core seems to be followed closely by the core plugging, or leaking. The former hopefully can be solved by flushing. The later requires replacement.

Watch the intake manifold , thermostat housing , waterpump drain holes and hose connections for signs of leakage. When things cool these are areas that air can be drawn into the system, as well as leak when under pressure. Watch for the crystals or moisture from the leakage.

Those running Dex seem to have more trouble with the above.

Now, some have no problems what so ever.

BADs Crew · Post by **BADs Crew** » Sun Oct 30, 2005 6:30 pm

It will be gone tomorrow. I hate Jiffy Lube but I know they have a power flush and will do it while I wait. You need to talk me into buying my new tires and rims now.

jeff024 · Post by **jeff024** » Mon Oct 31, 2005 12:49 pm

you NEED TIRES and WHEELS NOW !

BADs Crew · Post by **BADs Crew** » Mon Oct 31, 2005 1:49 pm

Yes I think I do. I'm sure my tires are made of defective rubber and they could blow out any day, and those rims. I think I'm seeing signs of hair line cracks. I bet those thing are bad too. I COULD BE KILLED.

rlith · Post by **rlith** » Sun Nov 13, 2005 8:50 am

Switch to a stant cap and the system will bleed properly.

BADs Crew · Post by **BADs Crew** » Fri Nov 25, 2005 4:23 pm

The cap was changed a while back. I had the time to drop by Jiffy Lube who I HATE !! but knew they had the power flushing equipment. I asked to make sure they could do the job and was told yes. I go get a cup of coffee and return to find some kind of vacuum system connected to my truck. I question the goofball as to what it is and goober tells me it a power vac that sucks all the fluid out of the system. THATS NOT A POWER FLUSH !! It just SUCKS !! ... So I let them finish and find the same DEX back in my system. Well it lasted for about 2 weeks now its gurgeling thru the heater core again. My Chevy dealer will be on it tomorrow morning at 9:30 am. I will never ever go to Jiffy Lube again. $70.00 for nothing. I'd be more pissed if I didn't turn it in on my expense repot at work.

BADs Crew · Post by **BADs Crew** » Sat Nov 26, 2005 10:43 am

O.K. at this point I will just wait for it to blow. I went to the dealer and they worked on the cooling system for 2 hrs. I pay the $109.00 and they tell me its repaired. I pull out of the parking lot and the water noise is still there so I go back. They get the mechanic that worked on it and he tells me its normal. He said every crew cab that he ever worked on sounds just like that. Is it just me? My Blazer doesn't sound like that nor did my truck make that noise last year. The heat works fine. The dealer said " Well we can change the heater core if you want" This is just what I don't want to do.

Post by **HenryJ** » Sat Nov 26, 2005 10:52 am

If you take the cap off while the system is cold, is there air in there , or is it full?

BADs Crew · Post by **BADs Crew** » Sat Nov 26, 2005 11:01 am

Full every time I have looked. It sounds like the anti-freeze is being drawn out faster that its going in. It only happens when I first start it or when I'm on the gas to take off or pass. After I drive it for a half hour or so I don't hear it as much. I do warm it up well in the mornings and before I leave work.

Post by **HenryJ** » Sat Nov 26, 2005 11:06 am

I would say it is not normal. I don't have that issue. Maybe mine is abnormal?

Did anyone ever flush your heater core? It could be that it is plugging?
After that replacement may be the next logical step.

BADs Crew · Post by **BADs Crew** » Sat Nov 26, 2005 11:18 am

Yes the whole system was just flushed. My heat will bake you in the truck. Thats what baffels me. When they flushed it all they got out of the system was a few specks of rust. Do you think I could be collapsing a heater hose? They look fine and are not soft when hot.

Post by **HenryJ** » Sat Nov 26, 2005 11:29 am

A restricted heater core will still get hot. The issue here is as you describe, trapped air. A partially plugged heater could possibly trap air and create some noise.
You said you had a power flush done. Did the hoses to the heater core get removed from the core at the firewall and flush through it? That may be what needs to be done to eliminate it as a cause. I have heard of those who thought the system was clean and found it had all accumulated in the heater core.

If you have no problems other than a little sound at first when it is cold, it may be a good idea to "get used to it" , or increase the clockwise rotation of the "annoying sound" cloaking device. (aka turn up the radio

)

BADs Crew · Post by **BADs Crew** » Sat Nov 26, 2005 11:36 am

Yes I will use the radio but I just found this doing a web search. I have a radiator pressure testing kit so I will use that method. I don't know if they pulled the hoses at the firewall

Air in Heater Core

Any time the coolant system is opened (by leak or at time of repair) there is the possibility that air can displace the coolant in the heater core. When this happens, an air blockage can form keeping the hot coolant from reaching the heater core. This is very similar to the old VAPOR LOCK in the fuel system. The air blocks the passage of the coolant causing a no, or insufficient heating problem.

Listed below are several ways to bleed this air from the heater core.

Remember you can receive 2nd degree burns from hot coolant so be careful

1. Check your shop manual to see if there are any OEM recommended bleeding procedures, and use that first.

2. Make sure that the radiator is full of coolant. Loosen the outlet hose clamp at the heater core. Start the engine and allow it to reach operating temperature. When the coolant starts to flow from the loosened outlet heater hose; tighten the clamp, and check the coolant level.

3. Loosen the outlet heater hose clamp at the heater core. Using a Radiator Pressure Tester, pressurize the radiator. When the coolant starts to flow from the loosened heater hose, tighten the clamp. Check the radiator for proper coolant level.

4. Install one of the aftermarket flush kit fixtures in the outlet heater hose by the heater core. This fixture has a garden hose connection. Open the garden hose connection cap and fill the radiator with coolant. If there is still air at the flush connection, use the Radiator Pressure tester to push the air out of the heater core. When coolant flows out of the fixture, seal the garden hose opening. Release the tester, and check for proper coolant level.

5. Be sure to check the OE coolant filling procedure in order to purge all air from the coolant system. One example of this would be found on some GM models, as the front of the vehicle has to be raised to get the air out of the heater core.

BADs Crew · Post by **BADs Crew** » Sat Nov 26, 2005 4:36 pm

Look what I just found. This might explain why the service manager said no comment when I told HER of the known problems.

http://www.girardgibbs.com/dexcool.html

Post by **HenryJ** » Sat Nov 26, 2005 4:49 pm

BADs Crew wrote:Look what I just found....
http://www.girardgibbs.com/dexcool.html

Dexcool class action lawsuit and Dexcool class action lawsuit.
Doesn't shock us here

I will never have a Dex problem since I saw the "handwriting on the wall" and made the switch to green nearly four years ago.

As I have said before there are two things to keep away from Dex...Heat and Air. Yours has air in the system therefore it must be eliminated to prevent the contamination.

Sad thing is I've seen 30 year old green that still looked viable, and two year old Dex-mud that looked like "Grannies jello".

jeff024 · Post by **jeff024** » Sat Nov 26, 2005 4:51 pm

I filled it out the cause of my waterpump failure was DEX

BADs Crew · Post by **BADs Crew** » Mon Nov 28, 2005 2:43 pm

After driving my truck today the problem is gone. I guess after the dealer flushed the system they didn't get all the air out of the heater core. I even tried to make it do it again. Good thing I didn't bash the dealer hard in my email. They called me today on my cell and I explained the issue and thanked them for their service. ( Hope I didn't jump the gun

)

BobbleSmitty · Post by **BobbleSmitty** » Thu Jun 26, 2008 4:32 pm

I'm starting to hear the same thing as I accelerate. I plan on flushing the system and replacing the cap. Does anybody know how much coolant I need to purchase, and when you guys say the green stuff, is there a specific brand out there that I should be looking for?