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11 comments
Associate

Join Date: Mar 2009
Posts: 35

2000 Chevy Cavalier - Heater Fan Blows Cold Air

12/20/2009 4:26 PM

I have a 2.2 Chevy Cavalier and it acts as tho there is air in the coolant system. The engine gets hot and I turnt the heater on and it blows cold air. The coolant fan does not blow. I replaced the thermostat and refilled it with coolant. A line wit the Thermostat in it going into the heater says do not vent while car is running. How do I vent it? The heater fan still blows cold air. Can you please help? Thanks

dnorris

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Guru
United States - Member - Member Hobbies - DIY Welding - New Member

Join Date: Mar 2008
Location: Southeast US of A
Posts: 526
Good Answers: 50
#1

Re: 2000 Chevy Cavalier

12/21/2009 12:04 AM

Your symptoms could result from different problems.

1) It may have air in it. Does yours have a bleed petcock at the thermostat housing? If not, then:

Fill the system full with coolant with the engine cold. Leave the radiator cap off. Crank and warm the engine. When the thermostat opens, the coolant level will drop. Top the system off, install the cap and check for proper heater operation.

Some tool suppliers have coolant fill equipment which may be helpful in filling and bleeding the system.

2) The heater core may be plugged. This is not an uncommon problem on these. Does one heater core hose get, hot and the other stay cold? You should check that. If so, you need to check by running water through the core to see if it's stopped up.

Let us know what you find.

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#3
In reply to #1

Re: 2000 Chevy Cavalier

12/21/2009 8:53 AM

There is a port where the thermostst houseing sets and a metal line comes out the other side of the thermostat housing and goes down the side of the engine around back of the engine and in to the heater. At the highest point in back of the engine there is a small screw in the metal line.On this line a note says " DO NOT VENT WHILE ENGINE IS RUNNING". I shut the car off after it heated up and My brother - in - Law unloosened the screw all the way out and no fluid or air came out, and it looked like there was a little check valve where the little screw came out. I will be sure the resivour is full and leave the cap off and start the car to try to see if it will fill up that way. Thanks for your help everyone. It give me something to try.

dnorris

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Join Date: Mar 2009
Posts: 35
#5
In reply to #1

Re: 2000 Chevy Cavalier

12/21/2009 5:30 PM

I decided to try back-flushing the radiator. I then refilled it with coolant and it is still ran on the hot side and I opend the little screw on the radiator line going to the heater and some air came out along with a little coolant. The Heater is now blowing warm air when it heats up but it is still running 3 notches past the 195 mark so it is still running on the hot side, and fan for the radiator is kicking on and running once the engine heats up. Both upper and lower hoses are getting hot. I cant figure out why it is running 3 & 4 notches past 195. Thanks for your help Guys.

dnorris

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Anonymous Poster
#11
In reply to #5

Re: 2000 Chevy Cavalier

01/18/2010 4:25 PM

Just a thought... I had just posted a note about my "Cavvie"... After the first bleeding of air, I was running at 3/4 scale, well above 195. One more bleed got me to the magic "3 lines" so many have been talking about. I bled again and though I did not hear any air or see any spitting, it did help again. Now I'm sitting at 195 all the time... I didn't think the third bleeding was necessary (actually, I cannot remember if I did it four times) but it did improve! I still say bleed, bleed, bleed. It doesn't seem to take a lot of air to cause a problem. I'd rather bleed too often than to have had the 3 lines above 195.

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Anonymous Poster
#10
In reply to #1

Re: 2000 Chevy Cavalier

01/18/2010 4:16 PM

Thanks for this information. I have a 2000 Cavalier. The lower hose blew after having been nicked by snow and ice thanks to this Iowa weather (I rammed up and over a snow/ice pile when sliding out of control). The weakened spot blew yesterday. I replaced the hose and the car took forever to heat up and then overheated. I replaced the thermostat (the old one had a tendency to stick a little). Same thing happened - cold for a long time and then it overheated very quickly.

Based on the advice, I bled the air out (actually had to do it several times). Each time I ran, filled, and bled (while shut off), I got a little more air and the result was a lower temp.


The car is running great - cooler than it has for some time. I am relieved and believe the car will continue to serve me well for some time to come. Thanks for your advice! I can't tell you how relieved and what a blessing this repair has been.

My advice would be to bleed, bleed, and bleed again. It took several times of bleeding to get the car working. And nope, no blown head gasket. Too many people had me worried.

My philosophy is that if it worked perfectly and suddenly changed, try to find something easy that you might have done rather than blaming the car. It always seems I am the one who introduces an extra variable like this extra air thing...

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Associate
Hobbies - DIY Welding - New Member

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Location: Wisconsin
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#2

Re: 2000 Chevy Cavalier

12/21/2009 3:30 AM

Standarded provided you with a lot of excellent information. In addition I am curious as to if you, or you had someone perform some maintenance on your cooling system. If for some reason you have lost, or have had some coolant changed or replaced, you could indeed have a void (air pocket) within your cooling system. I am not familiar with the Cavalier, but I know some General Motors products had ports (vents) that would allow a person to expel any trapped air. Just because it appears that the cooling system is at the maximum level (full), that could be misleading in the presence of trapped air. You may want to try opening your in-line vent when the vehicle is cold. If you detect a lower reservoir level after waiting several minutes, you may have solved your problem and just need to add the proper coolant mixture to the cold level as marked on the reservoir. You may even hear a gurgling sound when you open the vent. As I stated above, I am not familiar with a Cavaliers cooling system, and depending on where the vent line is located where connected to the thermostat housing, or thermostatically operated ports, if purging it at the in-line vent alone does not produce the desired results, you may have to make sure the coolant reservoir cap is loose so it does not create a vacuum not allowing the fluid to flow, and prevent any trapped air from escaping the cooling system. I hope this helps, and please play it safe and make sure the system is sufficiently cool before doing any of the above.........good luck.

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Anonymous Poster
#4

Re: 2000 Chevy Cavalier

12/21/2009 11:03 AM

The details in your post don't necessarily support the conclusion that the problem is an air lock.

I had an otherwise similar-sounding problem that turned out to be a broken control cable for the heater. It could also be a simple blockage (a leaf) in the warm air line, or ...

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Anonymous Poster
#6

Re: 2000 Chevy Cavalier - Heater Fan Blows Cold Air

12/21/2009 6:52 PM

Did you have this problem before you changed the thermostat?If not, make sure that it is installed in the proper direction.The spring part goes towards the block, otherwise. it will not open properly.

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Anonymous Poster
#7

Re: 2000 Chevy Cavalier - Heater Fan Blows Cold Air

12/22/2009 2:20 AM

Also be sure and check that you are putting the correct coolant in. Mixing the wrong coolants can result in harm to the system and even gumming things up and restricting the cooling. The color will usually tell you what you need to know. Green in green, orange in orange. You may need to drain, flush, and start over with all new fluid.

Good luck

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Associate

Join Date: Mar 2009
Posts: 35
#8

Re: 2000 Chevy Cavalier - Heater Fan Blows Cold Air

12/22/2009 8:33 AM

I may have made a mistake. I always buy the Yellow antifreeze. That was in it was orange. I added yellow to the orange. Would that cause it to run hoter then normal?

Thanks

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Associate

Join Date: Mar 2009
Posts: 35
#9

Re: 2000 Chevy Cavalier - Heater Fan Blows Cold Air

12/29/2009 7:37 AM

I did mix the antifreeze and went back and changed it. That cost $30.00 for 2 Gal. Thanks for that tip. I back flushed the radiator and that took care of the heater blowing cold air. I put a differant thermostat in it and it raised the temp gauge a couple notches, but still well under the over-heating mark. I checked with a Garage and they put a differant thermostat in it and that cost $55.00. It didn't drop the temp gauge at all. So in all it cost about $80.00. A lesson well learned. I need to make a note of this in the Operators Manual. Thanks everyone.

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