How to Fix Car AC that Blows Hot Air (AC Compressor)


Rev up your engines! [MUSIC PLAYING] It’s time for scottykilmer.com. If your car’s air conditioning
has stopped blowing cold, then stay tuned
because today, I’m gonna show you how to fix
a broken air conditioner. The first thing to
do is open the hood and check the pressure. So get a set of AC
gauges and hook them up. But don’t worry,
they don’t cost much. I got these at Harbor
Freight Tool for like $50. Then, you get the low pressure
fitting, the blue one, and then, look around the
air conditioning system to find where the low
side pressure fitting is. And there it as. The blue cap’s on top of it. You hook the fitting up to it
and turn the knob to open it. You can see on the gauge
there’s zero pressure, so all the refrigerant
leaked out. So what fun. Now, we gotta find
where the leak is. And to find leaks, I always
use ultraviolet leak dye. I inject it into the system. You just hook it up to the add
line and turn the handle once, and it injects the
dye into the system. Now, if you don’t
have this device, you can also buy
refrigerant cans that have the dye built in,
and you just add it in with the refrigerant can. Then, you add some
refrigerant to the system so you can get it running
and it’ll run the dye through to find a leak. Just open the valve, and you
can see refrigerant’s going in. And now, the
compressor’s running. Let it suck in the refrigerant
for about two minutes or so. And then once the system
is running by itself, it run for 10 or 15 minutes
to circulate the oil through the system to
find where the leak is. Now, not only can I get
my ultraviolet light out and look for leaks, but
I can hear it hissing. So let’s use our ears. I can hear it hissing, and it’s
the compressor that hissing. It’s leaking. But just to make sure,
I made some soapy water, and I’ll pour it on top of it. And sure enough, when I pour it
on top, you can see the bubbles and hear the hissing
change sound. So it’s time for
a new compressor. Now, I’ve already
made a video on how to replace an air
conditioner on YouTube, so you can watch that
for the whole thing. But basically, you
unbolt the lines. Just get a big wrench
and take them off. Pull them off. Then, take the four
bolts off the compressor and pull it out of the way. And out it comes. Now, when it comes to
getting a new compressor, my advice is always
buy a brand new one. The rebuilt ones
can be very iffy. I can’t tell you how
many times in the past I used to try to
rebuild compressors, then they’d come out and
bite me in the rear end, and I’d have to do
it all over again. Then, you bolt the
new compressor on and hook up the vacuum pump
to evacuate the system. You want to evacuate the
system for about an hour or hour and a half to
suck all the moisture out. Then, fill the system
with refrigerant. In this case, it
takes 600 grams. So open up the valve, and
let it start filling up. And now, we’ve got nice cold
air blowing in the face. So the next time your
car’s air conditioning stops blowing cold, now
you know how to fix it. And remember, if you’ve
got any car questions, just visit scottykilmer.com.