3 Common Signs Your TXV has Failed Causing Poor A/C System Cooling


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


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


come down eyesight barely climbs and the

low side drops there


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


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


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


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


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


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


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


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