When car is warmed up all it does is blow out cold air and then when my car overheats it blows out hot air

Tiny
ABBY12
  • MEMBER
  • 2002 CHEVROLET CAVALIER
  • 2.2L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 117,000 MILES
I would like to know if you can help me with my cooling system? When I'm driving my car and my car warms up it still blows out cold air from the heater. When the car starts running hot the heat will blow, but it goes into the red before it starts working. My car heats up pretty quick to 195 and I just got in it and drove it a block away. It should not heat up that fast. I'm getting ready to change the thermostat in it and hopefully that's what it is. If you could please help me narrow it down I greatly appreciate it. But when I turn on the heater and I know my car is warmed up all it does is blow out cold air. And then when my car overheats it blows out hot air. Can you help me solve the problem? Thank you
Saturday, November 2nd, 2019 AT 10:09 AM

6 Replies

Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

This sounds like it could possibly be two things that could be causing this. You got the first one, the thermostat. I would definitely start here, as it is the easiest one to do. The second thing it could possibly be is your vehicle's water pump may have failed. If you replace the thermostat and it doesn't fix the problem, then it's a very good bet that it will be your vehicle's water pump. But first, start with the thermostat. In the diagrams down below I have included the instructions for the removal and installation of your vehicle's thermostat from the vehicle manufacturer for you. Please go through this guide and get back to us with how everything turns out. If needed, we can also provide you with instructions on how to replace your vehicle's water pump too.

Thanks,
Alex
2CarPros
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Sunday, November 3rd, 2019 AT 1:43 AM
Tiny
ABBY12
  • MEMBER
  • 4 POSTS
Okay, I put the thermostat on I'm getting heat but only when I rev up the engine when I'm idling the heat get kind of cold not hot. I have water leaking out the back of the engine somewhere but it's cold water not hot. I'm still losing water somewhere. Can you help me? I flushed it out yesterday, but when I'm driving and I can only go down the street it would jump up to 195 but no heat will come out just yet. It goes past 195 just a little bit and when I'm driving it and giving it gas the heat will come out like I said. If I'm idling it would turn kind of cold no heat.
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Monday, November 4th, 2019 AT 5:50 AM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Okay, so that tells us that the water pump is probably going to be the culprit, here. But first, can you pinpoint where the the coolant is leaking at the back of your engine? This leak will definitely need to fixed as well. Double check heater hoses, and clamps and ensure there are no cuts, blow outs, etc. On the hoses, and that the hose clamps are tight. In the diagrams down below I have included the instructions from the vehicle manufacturer on how to remove and install your vehicle's water pump. Please check on the coolant leak, and remove and install a new water pump and report back here with how everything turns out.

Thanks,
Alex
2CarPros
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Monday, November 4th, 2019 AT 6:09 AM
Tiny
ABBY12
  • MEMBER
  • 4 POSTS
That's exactly what it was Alex it was a water pump. Thank you sir. I took it to a friend's garage and he had one of these pumps that he's stuck down in the radiator cap started pumping air in there and water started coming out from the bottom of the water pump. Everything is all good now I really appreciate your input thank you.
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Tuesday, November 5th, 2019 AT 4:51 AM
Tiny
ABBY12
  • MEMBER
  • 4 POSTS
I have the car listed above. I put a water pump in it, I put a thermostat in it and I'm still losing water. And my windshield gets foggy when I turn on the heat. Can you help me with the problem? Thank you
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Thursday, November 7th, 2019 AT 4:40 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

We can get you the instructions for replacing your vehicle's heater core, but for archival record keeping reasons, could you please ask this as a separate question. It will not help anybody else with this question look into this thread for the answer.

Thanks,
Alex
2CarPros
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Friday, November 8th, 2019 AT 12:53 AM

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