Where is the expansion valve located in the ac system
3 Common Signs Your TXV has Failed Causing Poor A/C System Cooling
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all right today I have a 2003 aviator it
has an AC concern where
cools down is the proper charge in it
see compressor on
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now what's going on here none of the
gauges we see
stop right now
when it comes down watch for it
waiting waiting waiting
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come down eyesight barely climbs and the
low side drops there
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with proper charge level so
at this point we need to go in when you
went through TXV
and see what's going on
another indication is when the vehicles
turned off the high side and the low
side do not equalize for a very long
time okay we just shut the vehicle off
and look at it okay so we're right
around 100 on the high side and we're
just sitting pretty not really moving on
the low side here these should be slowly
climbing and slowly dropping okay as it
equalizes through the system either fot
system or TXV system they will equalize
now this is going to equalize eventually
but you can tell right here they're
sitting there taking their time it's
been probably half an hour before
equalizes it should equal lies within a
few minutes minute two minutes then the
equalize about same pressure Lou this
it's taken forever to climb and drop
when it's equalizing so another good
indication that TXV is of concern it is
a screen or the belt itself okay so
here's a system diagram they're looking
a better indicator of exactly what's
going on here now this vehicle had no
cooling ability at all the compressor
would come on for you know five seconds
or so you saw it once it came on the low
side gauge just dropped the low-pressure
cycling switch cut the system off and
this is the cycle repeated now the high
side gauge it barely rose up above 100
or so very slow to climb did not really
do anything at all and that was a clear
indication that there was a restriction
in the system and there was a
restriction close to the compressor and
the way I figured that was think about
it it's dropping so fast it has the
proper charge level in this side is not
able to build okay so it means it's not
being fed refrigerant it's just that
simple
now the other thing is we have no
cooling in the cabin mainly because the
compressor like come on for a very short
period of time so not enough refrigerant
came through the evaporator coil here to
make that heat transfer and then
take it back out it's a low side here
okay now the other indicator was that
the high side gauge and the low side
gauge would not equalize when the system
turned off the system is free-flowing
except for the t --xv this is a metering
device that that separates the high side
and the low side and it's going to stay
open to an extent even when the system
is off it's all based on temperature in
the outlet side here okay so it should
be able to flow through and equalize
these two high and low sides so that was
another good indicator at that point a
very you know thorough visual of all
these lines okay and the the tubes in
the condenser all that was was needed to
make sure there was no restriction in
the system at that point it's time to
suck the system down and start looking
around you want to look inside there
either a line discharge side of the
compressor to make sure that there's no
desiccant that's floating around here
causing restriction okay especially in
the condenser or that the compressor
didn't come apart compressor comes apart
usually you know Xu bunch of metal
throughout system and they'll plug up
these very small passageways and
especially the orifice okay so the
easiest way to do that in this system
would be to take off the t --xv it's
right there and then you can look at all
your high and low sides and check for
that debris and then once you take it
off you can do a thorough visual of it
and we noticed that pintle inside of
here was it just fallen out so therefore
it never opened up and allowed the
refrigerant to come past it feed the
evap cool the vehicle down take that
heat with it and run back out the cool
side the low-pressure side here and then
start the process over again so as you
can see just by you know checking a few
different things paying attention to
different gauge readings we can tap into
the circuit and really see what's going
on
I need that visual to make a confirmed
you know diagnosis and that gave it to
me by looking at this internally and the
gauges now the reason why the last I
don't know why the last mechanic looked
at it and thought it was compressor
because when a compressor fails okay
and it's week you'll have low high side
pressures yes that's we have on this one
but you'll also have high low side
pressures because it's not generating
that draw on the low side to bring it
down to 25 35 psi it'll be around 50 or
60 so that was a misdiagnosis on their
part but we got it identified and that's
what's going on and that's how I was
able to zero in on the t --xv all right
we have a fix earlier we diagnosed
through system pressure diagnosis that
the th B was bad we knew that because
mainly because the system would not
equalize after you turn the key off and
that
is the gatekeeper between the high and
the low side so it's scoured the earth
to find a new txb from Motorcraft
I got one overnighted up here swapped it
in luckily it's very easy to get in
there and change it out and now look at
our persistent pressures they were a low
side and a high side 150 is about right
low scored THD systems are around 150
okay
now low side txb or fot system it's been
the rightness region 25 to 35 generally
okay and you can see our TX B is keeping
it right there okay it'll constantly
adjust keep the pressure on the low side
just right therefore you'll see these
pressures are pretty much staying the
same
there isn't much cycling with a pH D
system not to mention
down in here we can look at the
compressor much on there
and you can see it's time
it's not recycling long fall time
anymore therefore it's pumping up
throughout the system and more
importantly than pumping it throughout
the evap inside the cabin so we have a
heat transfer we get the heat out of the
cabin and back over here and the cycle
repeats
okay so let's show you what my system my
vent 10th is now on this car before it
set right around 80 or so sitting 5/8
wasn't doing anything because the
compressor come on start pumping and
shut up so it never pushed it enough
through to have that heat transfer okay
right there that 30 to the diagnosis in
the end we turn the system off was the
key so watch this while my turn the
system off my turn the vehicle
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okay so you see how they're continually
rising and continually dropping they're
equalizing they're able to equalize
through that TXV
now isn't metered or fits in there and
that bulb inside of there is going to
slowly change that opening in there so
on t --xv systems it does take a little
bit longer compared to fot system that's
constantly open it's just a metered tube
inside of there so you'll see this one
they'll constantly rise and constantly
drop until both the high and the low
side equalize before it just set there
at 30 and was like a hundred and never
really moved I mean for like an hour
it just never moved this one it'll
equalize in like minute or two they'll
be equalized so that was the big
indicator was a blockage in the system
and of course there was no kink lines or
anything like that okay so we identified
the culprit for your place the TXV
pressures are great cooling the cabin is
unbelievable so what happened to this
other gxv it's old one right here
there's no damage to it okay the
desiccant bag did not break open the
compressor did not come apart plugging
anything in here so why did it fail okay
I don't know exactly I have one theory I
took apart the valve down here and I
noticed the pintle on the sensing bulb
right here that actuate s' the pintle to
depress the valve in there that is held
in place and closed by a spring just
kind of fell out I'll show you here in a
second so that told me that this sensing
bulb had no control over that pintle
anymore and therefore could not depress
that valve in here and open it up so we
can get flow so it all made sense to me
plus the pressures while I was running
short cycling times going on extra low
on the low side and cutting off and then
of course our
static pressures when we turn the system
off that they would take forever to
equalize three good indicators that the
txb have failed alright so here's the
old TXV and this is considered a txb
block or the chrysler age valve they
used to call them basically what it
allows is for the you know diaphragm the
sense involved the pencil the metering
device everything to be all within this
block right here makes it great for
automotive AC systems so here's a
diaphragm up here and a sensing bulb and
everything inside of here it's all in
case inside of there and this is the way
it goes on assistants this is the inlet
side that's going to cause the
restriction the system there drop our
pressures and feed that evap okay and
here is the outlet side so it can keep
sensing the outlet side and based on the
outlet side temperature it's gonna
adjust the pressure down on this spring
and seat inside here I'll take it apart
here a second so this is constantly
adjusting based on the temperature that
refrigerant flowing past and coming out
of the evap okay and these are just a
bunch of sensing switches and stuff like
that for the system to control it so
this right here which you know I don't
think it's a part of your day but in a
little research down here is an
adjustable plug on here for your
superheat spring so you can attain the
right superheat for your system so of
course has a seal on a bunch of fine
threads okay and then it's just a
regular spring and a seat so you can see
a seat right there and that's all there
is to it down here so when you adjust
the depth on here in the tension on the
spring to adjust your superheat so if
you ever get one of these you see it
half unscrewed out of there oh I don't
know half out of there and you're like
didn't tighten it away from the factory
well guess what it's adjusted and stuff
in the factory don't touch it
okay so anyways so right down inside of
there that's that pintle
on the other end of this hole sensing
bulb and diaphragm okay and as it
increases in pressure in here it's gonna
push pressure down onto this right here
okay so push pressure right down into
that we're at seats and blocks the flow
refrigerant and it'll compress and as it
compresses it allows more and more
refrigerant to go right through here and
whack you in the head out the other side
to feed your evap okay so this is what I
found this when everything is clean the
system was not full of you know metal
and pieces and from a failed compressor
were failed desiccant bag there's no it
is clean look it's clean that's regular
dye in the oiling system it's beautiful
okay this is what I found not sure this
is right but this is the one thing that
kind of felt weird well there you have
it right there is that supposed to
happen this is the pintle inside of
there okay that goes up into there and
it kind of fell out way too easy okay it
just it's in here I tipped it over an
attachment mmm and just kind of fell out
didn't seem right at all I push it back
in at you at will and it just didn't
matter now this should be you know
pressurized in some sort of way and
therefore pressing down on it okay so
that was another indicator and I don't
that was right or wrong because I don't
think he's a part of it there's no
instructions hey you got failed TXV you
replace it right but I thought that was
kind of weird and the new one I did
check it on a new one and it didn't move
in there very much at all so I'm looking
at it making sure that nothing was
caught up in here causing any concerns
the spring had not failed the cup had
not failing let's see down here all
kinds of stuff like that you can still
get a lot of great information
out of the TX fee you know it's good
place for debris and stuff like that to
catch like this whole area in here okay
it just it be all caught up in here look
that's clean it's beautiful
so we knew at that point there was a
restriction and it was not allowing to
flow in and of course it could not come
out and feed the compressor so this is
very very expensive but the last guy
that worked on this put AC compressor in
here and now about five hundred dollars
this is about 165 and it was the correct
fix so that's about it hopefully you
guys enjoyed this video you know it's
nice diagnosing different things instead
of the same old same old
I don't you don't see TX fees fail too
often but this one is a classic example
of a failed TX v and it was mainly
diagnosed just by a manifold gauge set
and watching those pressures and seeing
you know what's going on the system and
think of it as a voltmeter for the AC
system you can see what's going on and
those circuits in there soon
I will be letting you guys know about
some great new exciting information here
on the channel until then I'll see you
next time guys
