Heater not working

Tiny
RANDAR38
  • MEMBER
  • 2000 CHEVROLET LUMINA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
Idles in driveway over 1 hour heat works fine temp gage little past halfway next day drive 4 miles to work gage past 260, no over heat light, heater blowing cold air. Drive home that afternoon again heater works fine, gage around 190 1/2 mile from home cold air, gage up to 260. Pop hood sudsy water boiling out of coolant tank. Have changed water pump, thermastat, and sensor next to thermastat. Thankful for any and all help
Saturday, January 5th, 2008 AT 5:25 PM

36 Replies

Tiny
BLACKOP555
  • MECHANIC
  • 10,386 POSTS
Are you certain that your cooling fans are turning on when the car is reaching the proper operating temperature.

This guide will help

https://www.2carpros.com/articles/car-heater-not-working
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Saturday, January 5th, 2008 AT 7:36 PM
Tiny
RANDAR38
  • MEMBER
  • 2 POSTS
Only seem to come on when I turn control to a/c
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Sunday, January 6th, 2008 AT 4:27 PM
Tiny
BLACKOP555
  • MECHANIC
  • 10,386 POSTS
Ok check your relay or hardwire it to stay on and see if it works just fine. Also change your radiator cap, and see if that stops the overheating and bubbling problem.

And for the heat problem feel the heater core hoses when there is no heat and let me know if one hose is hot, no hoses is hot, or both are hot.
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Sunday, January 6th, 2008 AT 6:32 PM
Tiny
LISADOB
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET LUMINA
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 194,000 MILES
What could be the problem? The air blows but it never warms up when you have the heat on. Is there an easy fix for this?
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
It sounds like the electric actuator for the heat blend it not working. There are two actuators and the right one is the one I suspect to be non operational. Or your heater control valve is stuck closed.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
JCORCIONE
  • MEMBER
  • 5 POSTS
  • 1999 CHEVROLET LUMINA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 145,000 MILES
We have a 99 chevy Lumina 3.8 Litre engine. The radiator was replaced 18 months ago and upper and lower radiator hoses and thermostat were replaced about 5 months ago. Now that it seems to be getting cooler outside the heater is blowing luke warm to cool air at operating temp. We also noticed some steam or smoke comming from the front driver side which looks like it is comming from underneath the hose leading to the thermstat. Coolant level is fine in the reservoir and radiator.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi:
If you had the hose replaced, check to see if it's tight. Also, mak sure the t-stat housing is tight.

The heater is another issue. The heater core may be plugged. One easy way to check is to locate the heater hoses under the hood. There is an inlet and outlet. With the engine running at operating temp and the heater on, feel both hoses. One should be VERY HOT and the other just slightly cooler. The hottest one is the inlet. The SLIGHTLY cooler one is the oitlet. If the outlet is cold or MUCH cooler than the inlet, it sounds like the core may be partially plugged and need replaced.

NOTE: THE HEATER HOSES HAVE THE POTENTIAL OF REACHING TEMPS. OF OVER 200 DEGREES. BE CAREFUL!

I hope this helps. If you have any other questions, let me know.

Joe
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
JCORCIONE
  • MEMBER
  • 5 POSTS
Thanks for the response. My thermostat was bad I replaced it and BAM all working again.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
MFULLMAN
  • MEMBER
  • 2 POSTS
  • 1998 CHEVROLET LUMINA
  • 144,000 MILES
I have a 1998 Chevrolet Lumina with a 3.1. At the end of last winter the heat was on whether the heat control was set to cold or hot. Then suddently it only blew cold air no matter where heat control was set. Now it is winter again and still blows cold air. There is no overheating problem, the heater hoses are both hot, the fan works fine, the climate controls work fine, vent, bi level, defrost, etc. It just blows cold air, I read about temperature control solonoids and actuators that control the flow of heat into the car, where would these be located? Or is it something else like the thermostat?
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Try pulling hvac fuse first for 60 seconds with key on then reinstall it may reset actuators. Not knowing if you have dual zone you may have two of these. Also check for a vacuum leak start at engine and work through heater/
Image (Click to make bigger)
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
MFULLMAN
  • MEMBER
  • 2 POSTS
As it turned out it was the electric actuator or the lack there of one. I am wondering if a certain repair shop didn't remove it in an attempt to get some money out of me. I discovered this by going to a junk yard and finding a car just like mine and examining the heater box on that one, mine was certainly non-existent only a dangling wire. Can you believe that? It just goes to show find a good pull and pay junk yard and do the troubleshooting yourself.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Well I don't know the circumstances and if it were owned by aprevious owner that may have been done to make the a/c work. But there are unscrupulous people out there.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
08COURTNEY
  • MEMBER
  • 1 POST
  • 1998 CHEVROLET LUMINA
Engine Cooling problem
1998 Chevy Lumina 6 cyl Automatic 102000 miles

3 weeks ago replaced themostat in car because of no heat. Car ran great until this weekend. Low coolant light came on. Added antifreeze. Car temp immediately went sky high and heat quit working inside car. Found a small hose around thermostat that was unclamped. Reclamped, still temp running high and no heat. Coolant full, will not take anymore. What might be the problem?
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If the t-stat is new and the coolant is full, either you have a plugged radiator or blockage in the engine. Check this. With the engine running, warmed up, and the heater on, feel both heater core hoses. Both should be hot.

Let me know what you find.

Joe
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
SJL5011
  • MEMBER
  • 1 POST
  • 1997 CHEVROLET LUMINA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 70,000 MILES
The heater will take like 30 minutes to heat up. It will then blow warm air for any random variation of time could be a minute could be an hour. And it will be bursts of cold air. It almost as if it is switching from hott air and cold air randomly. Not great with cars but know a little. Any help is appreciated, and please explain throughly. Thanks
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
RENAUDTN
  • MECHANIC
  • 636 POSTS
Is your engine slow to warm up?
If so, your thermostat is stuck open and you'll need to replace it. One way you can check it is by turning on your car, and feeling the upper hose with your hand. There should be no coolant going thru this hose until the car is at normal operating temperature.
If you feel coolant going thru the hose as soon as you start your car or before your car reaches normal operating temp, you know your thermostat is defective.

If your thermostat is OK, it's likely one of the following:
- low coolant level
- Clogged heater core
- defective heater valve
- vacuum leak
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
DERONTA
  • MEMBER
  • 5 POSTS
  • 1997 CHEVROLET LUMINA
  • 212,000 MILES
Replaced therm radiator and waterpump. Heater blows cold air temp rises and car overheats can u tell me wht I can do to stop overheating and gt heat
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
You may have air in the coolant system.
To bleed it allow the car to cool and remove the radiator cap. Turn the heater setting all the way hot. Allow the car to reach operating temprature and then top off radiator and reserviour with a 50/50 mix of anti-freeze and distilled water.
Also replace the radiator cap.
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
DERONTA
  • MEMBER
  • 5 POSTS
  • 1997 CHEVROLET LUMINA
  • 212,000 MILES
Replaced thermostat waterpump and radiator. I bled the system. When I drive the car temp rises an heater blows out cold air. No water mixing with oil so what could keep causing car to overheat
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)
Tiny
MEKANIC4755
  • MECHANIC
  • 85 POSTS
Need more information engine size, are you sure the radiator fans are working, do you have the thermostat installed properly? These enegines take a long time to bleed air out of the system. If all these are correct, you may have a blown head gasket, leaking into the cooling system. What exactly was the car doing to start with, no heat or overheating and no heat, leaking water. You will have to be a little more specific. Thanks for using 2CarPros
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Sunday, August 18th, 2019 AT 9:37 AM (Merged)

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