TOP 5 REASONS why your car heater is not working. Cheap and easy fix: car heater blowing cold air

if you are getting no heat coming out the vents the first thing you can check is your engine temperature normally your engine should reach its operating temperature within 10 to 15 minutes of operating the vehicle but if your engine temperature lingers at the bottom of the gauge for 30 minutes you may want to look into replacing your thermostat because the thermostat is responsible for the engine to reach its operating temperature in a timely manner if the engine warms up like it should but you're still not getting any heat the next thing to check is your coolant level see the engine cooling system circulates hot coolant from the engine through the heater core a small radiator behind the dash to make it hot but the heater core is usually placed above the rest of the cooling system so if there is a leak in the system it will be the first component to lose coolant supply in which case you may notice water flowing sound behind the dash when checking the coolant level common mistake people make is they check only the overflow bottle don't forget to check the radiator too make sure the engine is cold before opening it if you have an expansion reservoir make sure the coolant level is within the cold fill range when the engine is cold nine times out of ten topping off your cooling system will take care of your heating problem however sometimes low coolant level can contribute to formation of air pockets in the cooling system so if your heat starts to work on the throttle but goes away at idle consider looking into air bleeding procedure as well the third reason your heater core is not warming up is a restricted coolant flow due to a clogged up heater core or pinched heater hoses if you open the hood on any car and look at the very back of the engine compartment you'll find two rubber hoses going into the firewall these are heater core hoses providing hot coolant from the engine to the heater core so the next thing you want to do is make sure they're not pinched or kinked they can get jammed under something like an engine cover or get routed poorly after repairs on some cars you may also find a heater valve placed in between the heater hoses it can be operated by a cable or vacuum or electronically refer to your service manual to make sure your heater valve works properly if the hoses don't seem to have any obstructions next thing to check is whether the heater core itself is clogged up if when you opened the radiator to check the coolant level you saw that it is all rusty and gunky on the inside you can bet your heater core doesn't look much better plus it is a lot smaller than the radiator and therefore is easier to clog up the simple way to check it is to compare the temperatures of the two hoses but what people often fail to remember when they perform this test is set the temperature setting on hot and the blower motor on high to cool down the heater core as much as possible on a properly operating heater core the temperature drop between the two hoses should be around 25 to 30 degrees fahrenheit on a clogged up heater core it can be more than double that depending on how clogged it is the temperature difference can be so drastic that you may be able to feel it just by touching the two hoses one will be hot and the other one will be really hot but of course the best way to check the temperature difference is to use an infrared thermometer like this they're usually 15 or so and can give you an actual value of what your temperature difference is i'll add a link in the description if you want to get one so if you suspect a clogged up heater core consider flushing your cooling system with some radiator flush or at least try flushing out the heater core so these are the three things that can affect your heater core temperature engine temperature coolant level and coolant flow but even if our heater core gets nice and hot we may still have no heat coming out the vents let's get inside the passenger compartment and review the second part of the heating system called air distribution system which blows air across the heater core and redistributes the hot air throughout the passenger compartment often a customer would come in complaining my car is not blowing very hot where in reality the air is plenty hot what they have is restricted airflow so if you turn your blower motor full blast yet you can barely feel any air coming out the vents check your cabin air filter it is usually hidden behind the glove box or under the hood by the firewall if your blower motor doesn't seem to come on at all check your owner's manual to find fuses and relays responsible for the blower motor operation another common problem with the air distribution system is the blend door operation see the heater core is placed inside of an hvac housing a big plastic box behind the dash heater core shares room with an evaporator core for air conditioning and the blower motor that takes air either from the outside or from the passenger compartment and blows it across the evaporator core first and then there is a blend door responsible for letting the air flow across the heater core bypass it or be somewhere in the middle after that there is a set of mode doors directing the air flow to the vents to the windshield or to the floor here is an example of a real hvac housing on the far right we have a blower motor bolted on right next to it is the blower resistor allowing the blower motor to spin at different speeds right above the blower motor is the recirculating door letting the air come in from the outside or recirculating the passenger compartment air the next thing we see is the evaporator core for air conditioning and then there is our heater core if we look underneath there should be a motor here that turns this shaft that's our blend door opening and closing access to the heater core and after that the air gets distributed to the windshield to the vents and to the floor on most modern cars the blend door is driven by an electric motor called blend door actuator controlled by the heat control unit and the easiest way to check if you have a blend or problem is set the mode door to your vents turn your blower motor speed to medium maybe medium high and switch your temperature from cold to hot and listen for a change in airflow properly working blend door will redirect the airflow from bypassing the heater core to flowing across it which will cause the airflow sound to change now on some older cars blend doors are cable operated on cable operated blend door you will have an immediate response in airflow with the door flopping sound at the end of the turn with electronically operated blend door you will have a slight lag between the knob and the blend door if you hear no change in airflow you most likely have a blend door problem of some sort especially if you hear popping your blend door could be broken off and or stuck in always hot or always cold position and the actuator would keep spinning and popping as it's trying to move the broken blend door you can try removing your heat control unit and see if your blend door is cable operated or moves electronically if it's cable operated maybe the cable got disconnected somewhere see where it goes and if everything moves freely you may have to remove more things like your radio and your glove box to look around the hvac housing usually you can just squeeze the sides of the glove box to move it out of the way and now we can see where the cable goes if your heat control unit is electronic see if you can find any actuators attached to the hvac housing as you can see i had to take a few things off to find them and with everything turned off your engine your blower motor just the key in the on position see which actuator responds to the heat control knob it should make some turning noise or start popping remove inspect see if it needs to be replaced or if your blend door is broken unfortunately if the blend door is broken it usually means the whole dash has to come out hvac housing has to be removed and split open in order to replace it however on some cars the blend door failures were so common that the engineers came up with an in-car repair procedure where the side of the hvac housing gets cut out and the blend doors get replaced with everything still on the car so do your research to see if your car is one of them hopefully this video helps you narrow down what part of the heating system needs further attention in your car give it a thumbs up if it was helpful share your experience and feedback in the comments below thank you for watching good luck and take care

Channel: Make It Easy Mechanic

Views: 613,588

Keywords: car heater, car heater not working, car heater blowing cold air, car heater not blowing hot air, car heater core, why is my car heater no getting hot enough, car heater not blowing air, car heater blower not working, car heater blowing warm air only, no heat in car blowing cold air

Id: te6njeydYC0

Length: 10min 9sec (609 seconds)

Published: Mon Oct 05 2020