How to Fix a Car with No Heat (Easy)

hey guys chrisfix here and with the

colder weather around the corner today

I'm gonna show you how to diagnose a

problem where you don't get heat in your

car truck before we begin anything turn

your car or your truck to the run

position and you just want to make sure

that your temperature gauge here is low

you do not want it to be in the middle

or high because the first test we're

gonna do is to check to make sure that

we have enough antifreeze in the car and

you can't check the antifreeze when the

engines hot you get heat in your car

because that radiator fluid that gets

really hot runs through the engine

through the piping into your cabin where

there's like a mini radiator that mini

radiator holds hot coolant it's called

your heater core and then a fan blows

over your heater core and that's how you

get hot air and then when that coolant

is cooled just a little bit because you

have a fan blowing over it it gets sent

back into the engine so if you don't

have enough coolant your engine might be

able to run at the correct operating

temperature but because the heater core

is so high up into the vehicle there

might not be enough fluid to get into

here and give you heat inside your car

so the first step we're gonna do since

the engines still cold we're gonna go

check the radiator and see if there's

enough fluid in here you just spin it

counterclockwise and then when it won't

spin any more you press downwards and

spin it until it comes off Wow I'm

definitely going to need to change this

fluid very soon you can see it's all

gunked up and that will bring me to

another reason why you might not have

heat but we'll get to that a couple

seconds you can see the coolant is right

up to the top here so this radiator is

filled and now we'll put the cap back on

and just twist this clockwise until it

firmly snaps into place you wanna make

sure that this is on correctly because

this is a pressurized system your car

might not have a radiator cap like this

so just check your owners manual it'll

tell you how to check your coolant

that's just one of those basic things

that every owner's manual has also you

might have a coolant reservoir that you

should check you could just go in here

and see if there's any coolant and in my

case there isn't any coolant so I'm

going to add a little bit when you're

adding coolant to this you want to go

and look there's a cold fill line you

can see it all the way down there it

says cold fill that's where you gonna

fill this up when the engine is cold so

I'm going to add some coolant make sure

you check your owner's manual to make

sure you're adding the right type of


okay so now we know that our radiator is

filled and we topped off our coolant

reservoir now we can properly test the

heating system and see if we have heat

filling your radiator up with just a

little bit of coolant like this might

just be an easy fix for your no heat

problem so now we're gonna go for a ride

so that we could heat up our engine you

want the temperature gauge here to be

between the C and the H right in the

middle and that's how you know your car

is heated up and at that point you

should have heat in your car so I'm just

finishing up my drive you can see the

engines at operating temperature and now

that the engine is warmed up let me show

you the other steps to diagnose a

vehicle when you don't have heat so I've

been driving around for a little while

and that gauge has been pretty stable

right there but if your car is

overheating then the reason why you're

not getting heat because the water pump

isn't working

typically a bad water pump will leak and

the impeller will still spin but if it

doesn't spin the hot coolant won't be

forced into your heater core or even

your radiator so your engine will

overheat and you won't get any heat in

the cabin you also might have a problem

where your car never gets hot it doesn't

get up to operating temperature and this

could be due to the absence of a

thermostat or your thermostat stuck open

to find your thermostat all you have to

do is follow that top radiator hose into

your engine once you find your

thermostat all it is is two bolts one

there one there you unbolt those you

take the old thermostat out put the new

thermostat in and close it up so in this

case since our temperature gauge is

right in the middle

we know that the thermostat and water

pump are good just to let you guys know

in my truck I actually have heat

everything is fine I'm just going

through steps for you so if you don't

have heat or if you have a little heat

you could diagnose the problem yourself

so after the car is warmed up we're

going to turn the heat on all the way

and then we're gonna put the heat on the

floor so my fan is working when it's on

low it works when it's on medium and it

works when it's on high if your fan only

works when it's on high

and you're not getting heat or a fan on

the lower settings then your blower

motor resistors probably bad and I have

a video on how to replace that it's not

a big deal it's a pretty cheap part and

it's pretty quick and easy to replace

now if your fan doesn't work at all you

have it on all the different speeds and

it's not working then your blower motors

probably bed and I also have a video on

how to replace that but if your fan does

work and you're still not getting heat

or it's not very hot there could be

other problems let's say the air coming

out isn't really hot like it's a little

warm but it's not as hot as it should be

what that typically is caused by is a

quad heater core to check for a clogged

heater core make sure you heat is on and

we're going to go outside to the engine

compartment when we look at our engine

compartment what we want to do is we

want to go back to the firewall

typically on the passenger side or

somewhere near the middle you're gonna

find two hoses these two hoses go into

the firewall and these are your heater

core hoses so with these two heater core

hoses what you want to do is you want to

touch them you want to make sure that

both of them are hot right now it's

about 35 degrees on the blacktop so

imagine how cold it is outside and then

I'm gonna turn the laser on so you can

see where I'm aiming I'm aiming right on

the hose and it's about 140 degrees now

I go to the other one same temperature

140 so both of these are the same

temperature they're both warm they're

hot to the touch make sure you don't

burn yourself when you're doing this so

I know my flow is good so if you have

one that's hot and one that's cold the

first thing you want to do is check the

heater control valve which is this right


in my case my heater control valve is

run by a vacuum in your case it might be

electronic or mechanical either way all

you have to do is turn the heat on and

shut the heat off and see if this moves



so if your valve is working it'll move

in and out if your valve isn't working

it won't move now if your heater control

valve isn't working you're not gonna be

able to get heat because it won't let

coolant flow into your heater core and

if that's the case you just need to

replace one of these now if you just

want to set this up real quick so that

you have heat without fixing this all

you have to do is take the vacuum line

off and then clogged up the vacuum line

here you don't have a vacuum leak now if

it doesn't open up when you take the

vacuum line off just manually open it up

you can even tape it or rubberband it to

something so that it stays open now

that's just a temporary fix but it's

something so you have heat if you have

an electrical one of these you can

unclip it from the wiring harness and

test it to see if it's getting power

when you turn the heat on if it's

getting power your heater valve is bad

if you're not getting power then there's

a problem with the hvac under the - if

your car has a mechanical heater control

valve when you turn the dial for your

heat you move a cable that opens the

valve instead of using vacuum or

electrical motor this cable can

disconnect and many times you just need

to pop it back into place to fix the

problem and remember if you can't find a

heater control valve your car might not

use one so don't worry in my case this

works fine so let's move on to the next

thing to diagnose the other reason why

one of your hoses will be hot and the

other will be cool or slightly warm is

because you have a clogged heater core

you can attempt to reverse flush the

heater core by taking off both of the

hoses and running water through them to

flush any gunk that's in there and might

be clogging it up you could use a garden

hose but make sure you use very low

pressure because you could damage the

heater core I have a video on flushing

the heater core and the link to that

video will be in the description now

let's say both of your lines are cold

and your heater control valve is working

properly you might have air in the

system since this is one of the highest

points in your cooling system there's a

good chance that air could get caught in

here to fix that all you have to do is

bleed your cooling system and sometimes

with the heater on a few good revs of

the engine will force that air out and

that coolant in now one of the last

things I'm going to go over to diagnose

the heater system if you did all that

and none of that worked well you could

have a bad blend or actuator in some

cars like this it's mechanical in other

cars it could be moved with an

electrical motor or using engine vacuum

now what a blender does is it's a door

that blocks

either the air-conditioner or the heater

so if you turn your temperature to the

cool position right now the blend door

will be blocking the heater core you

don't want air from the heater core

because you just want cold air now if

you turn your heat on then the blend

door will be blocking cold air coming

from the car the blend door can also

allow both hot and cold air to come in

at the same time to get a desired

temperature typically if you change your

temperature quick like that you'll hear

like a knock and that's the blend or

just slamming shut I'm gonna change this

quickly and we'll see if you could hear

it so in mine you could hear the blend

door opens and closes it's just that one

click or one knock and it's functioning


if you don't hear that on yours when you

turn this quickly or if you hear a

clicking so if I go from here to here

and it's making like a deer stripping

noise or like a plastic click like click

click click click and then it stops that

could be the blend or actuator which is

up under the dash and it's connected to

the blend or and it's just an electrical

motor and the gears strip overtime and

then your blend door won't move so it'll

be stuck in either this position or

it'll be stuck in that position either

allowing cool air or hot air into your

car so all you would have to do is

replace that blend door actuator and

that'll fix the problem or in this case

since it's mechanically connected from

the switch to the blend door you can

look behind here for a connector that

popped off and just reconnected the same

goes for a blend door that works off of

engine vacuum just look for a loose

vacuum hose and reconnect it now these

are the most common problems for no heat

situations I hope this video helps you

diagnose your problem as always you

could comment below with any questions

also remember to give the video a thumbs

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button the top tip for this video is a

basic maintenance tip on how to prevent

a no heat situation because nobody wants

to be left in the cold for their Drive

the best way to prevent many no heat

problems is with a coolant flush every

few years and now if you're unsure if

your coolant needs changing one way to

test it is with the multimeter with the

engine cooled down take the radiator cap

off now start your engine

and put the multimeter on 20 DC volts

and take one of the leaves and put it in

the coolant but only touch the coolant

not the side or the metal of the

radiator down below it and take another

lead and put it on the ground if the

reading is point three volts or more you

probably need to change your cooling

there are other methods to test your

coolant and also I'll get more into this

multimeter method in another video and

the link to that video will be in the

description below