Q: I poured antifreeze in my car and it's still blowing out cold air when I turn the heater on

asked by on November 10, 2016

I'm trying to use my heater and I noticed my temperature gauge was more than half so I put antifreeze in it, now it's fluctuating. Why isn't my a/c blowing heat?
Now it's in park and the temperature is at the halfway mark

My car has 110000 miles.
My car has an automatic transmission.

Thermostat Replacement $157.20 - $759.78 Get a Quote
Heater Control Valve Replacement $168.19 - $1039.92 Get a Quote
Heating AC Inspection $94.99 - $114.99 Get a Quote

Hello. There are a couple of things to check here. When the antifreeze was added, was the cooling system thoroughly bled (with the heater turned to "Max" heat and fan? There could be air bubbles in the engine or heater core - which don’t transfer heat.

You mention the temperature at the gauge is "fluctuating". A properly working thermostat should keep the temperature steady at the middle of the gauge. It’s also possible your heater control valve is malfunctioning, not allowing hot coolant into the heater core.

I would recommend having an expert inspect the heating system in order to pinpoint the correct repairs for your situation.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

What will set off the airbags?
The airbags are made to inflate in the case of a crash, but how severe of a crash does it take to deploy the airbags? This is a fairly common question, but doesn’t quite capture the complexity involved in the...
Problems with windshield wiper.
Hi, I have seen this before, and the repair is usually pretty simple. The wiper arm drive is a cone, and the wiper arm just slides on to the drive. A nut usually puts pressure on the arm down onto...
Headlights and taillights don't work
Hello. If both of these stopped working at the same time it is usually the switch. This is the most common failure on this car. I would usually check the wiring to the switch for voltage first before replacing the...
Linkage not working correctly
The problem most likely lies in either the shifter assembly or the linkage rod has become disconnected. The shifter and linkage rod need to be inspected for failure. You may want to enlist the help of a mechanic, such as...
Electrical problems on a 1990 Ford Mustang GT
You've got electrical problems. First, you'd want to check all the fuse boxes and all the fuses (https://www.yourmechanic.com/article/how-to-check-fuses-by-rocco-lovetere) and relays. See if anything's blown or not getting power and if anything's out. If they all went out at once, you've...
Damage to my brake booster
Brake fluid in the brake booster is definitely a sign of a leaking master cylinder (https://www.yourmechanic.com/services/brake-master-cylinder-replacement) as you know. Additionally, brake fluid in the brake booster will also cause deterioration in the diaphragm resulting in failure leading to vacuum leaks...
Stops accelerating while driving - 2002 Ford Crown Victoria
The problem is most likely in the fuel supply system of the vehicle. When the vehicle is running okay, turn the key on and off to see if you can hear the fuel pump in the tank. Now when the...
Follow Up for *Tim Charlet* -- Workspace - Incline (2)
Hi there: Thanks for the reply and for reaching out. Let's address each one individually. First, as long as the rear wheels are also chalked; this should be OK; but again, it's always at the mechanics choice on whether or...
Truck won't start, but lights come on and flicker
What you are describing sounds like a faulty starter solenoid. A faulty starter solenoid (https://www.yourmechanic.com/services/starter-replacement) will generally produce a clicking sound when turning the key. The starter solenoid is located on the starter and has internal electrical contacts that transmit...

Related articles

The Best Used Cars to Buy for Occasional Drivers
Not Not everyone relies on their car on a daily basis. Maybe you aren’t the type that deals with a daily commute, and running from here to there constantly. If that’s the case, you may be looking for a car...
Symptoms of Bad or Failing Heater Hoses
Common signs include coolant leaking, hoses cracking, and engine overheating.
How to Flush Out Your Heater Core
If your car’s heater (https://www.yourmechanic.com/article/how-to-buy-a-good-quality-heater) doesn’t seem to be working too well, it might be time to flush it out....