Dlhhedge814

I'm trying to locate the orafice tube to install
a new one, beleive the existing one is plugged,
have good press. untill the compressor kicks in
the press. drops to zero and compressor shuts down
for a few seconds then back on.

Tom Adkins

Dlhhedge814 wrote:
> I'm trying to locate the orafice tube to install
> a new one, beleive the existing one is plugged,
> have good press. untill the compressor kicks in
> the press. drops to zero and compressor shuts down
> for a few seconds then back on.
>

Your problem is caused by low refrigerant charge. If you had a proper gauge set that
would read high and low side pressures, you would see the high side start to climb
while the low side drops.
The usual culprits for leaks are any of the spring lock couplings, and the
compressor shaft seal or body seals.Look for oily residue around all of the
connections, the dirty ones are leaking. Same with the compressor, oil behind the
pulley=shaft seal, oil on the body=housing seals. If the truck is a late
80's-early90's vintage another problem is rust on the condenser tubes. Look for the
tube coming out of the lower right side of the condenser that runs up to the connector
(look through the grille, passenger side). If there is flaky rust on the tube, a new
condenser is in order. There could be leaks in other places, but these are the most
common.

Dlhhedge814

I have a set of guages that read high and low side,
I've checked for all the leaks already, and just in case tried to give it
a charge, but it would not take any. That is the reason I beleive it is
the orafice tube, but can't seem to find it. as you suggested I checked
for the rust but can find none. I really need to find the orafice tube to
change it anyway, can you help me locate it, I've checked the sevice
manual but, it gives me no location for it or no instructions how to go
about changing it.

Sharon K.Cooke

Dlhhedge814 wrote:
>
> I have a set of guages that read high and low side,
> I've checked for all the leaks already, and just in case tried to give it
> a charge, but it would not take any. That is the reason I beleive it is
> the orafice tube, but can't seem to find it. as you suggested I checked
> for the rust but can find none. I really need to find the orafice tube to
> change it anyway, can you help me locate it, I've checked the sevice
> manual but, it gives me no location for it or no instructions how to go
> about changing it.

If you have the gauges, what are your readings? Most importantly, what is the
static (engine off) pressure reading at the low pressure port at say, 80º F.
ambient temp?

Shoe Salesman

"Dlhhedge814" <dlhhedge814@aol.com> wrote in message
news:4712708cb1ccd6e21721349ff6c21180@localhost.talkaboutautos.com...
>I have a set of guages that read high and low side,
> I've checked for all the leaks already, and just in case tried to give it
> a charge, but it would not take any. That is the reason I beleive it is
> the orafice tube, but can't seem to find it. as you suggested I checked
> for the rust but can find none. I really need to find the orafice tube to
> change it anyway, can you help me locate it, I've checked the sevice
> manual but, it gives me no location for it or no instructions how to go
> about changing it.

A plugged orifice will cause high side too high, lowside too low. It is has
to be in the small line going into the cab. On Fords it is sometimes in the
line itself so you have to replace the line. Or it could be very near where
that line goes into the cab at the firewall.

C. E. White

See

http://www.ford-trucks.com/forums/sh...d.php?t=140545
http://cv6.fakeleg.com/techfiles/ac.....servicing.pdf
http://www.ford-trucks.com/forums/sh...64#post1993464

Ed

Dlhhedge814 wrote:
>
> I have a set of guages that read high and low side,
> I've checked for all the leaks already, and just in case tried to give it
> a charge, but it would not take any. That is the reason I beleive it is
> the orafice tube, but can't seem to find it. as you suggested I checked
> for the rust but can find none. I really need to find the orafice tube to
> change it anyway, can you help me locate it, I've checked the sevice
> manual but, it gives me no location for it or no instructions how to go
> about changing it.

Tom Adkins

Dlhhedge814 wrote:
> I have a set of guages that read high and low side,
> I've checked for all the leaks already, and just in case tried to give it
> a charge, but it would not take any. That is the reason I beleive it is
> the orafice tube, but can't seem to find it. as you suggested I checked
> for the rust but can find none. I really need to find the orafice tube to
> change it anyway, can you help me locate it, I've checked the sevice
> manual but, it gives me no location for it or no instructions how to go
> about changing it.
>

The orifice tube is, I think, part of the liquid line and not replacable. Your
problem is not a plugged orifice. Jumper the cycling switch on the accumulator while
charging and place the refrigerant can in WARM water. If the gauge is reading the low
side pressure, the system will pull the refrigerant in. Always charge through the Low
side port, NEVER the high side. When fully charged the inlet and outlet of the
evaporator should be about the same temp and the high side pressure should be about
2.5 times the ambient temperature. If the high side ever goes up over about 275 there
is a problem, very likely a bad fan clutch or air in the system. If you have opened
the system looking for the o-tube, you MUST pull it into a vacuum before charging. It
won't cool and the high side pressure will be WAY high and could damage the compressor.

Dlhhedge814

Thanks for the info, I guess thats why the service manual dose not refer to
how to change the O-tube, as a last resort I was going to try vacuuming out
the system and giving it a fresh charge, it had been working fine untill
about 2 weeks ago. I've tried jumping the low press. switch and adding gas
but that didn't work it just would not take any, like the system was full
but the guages read zero press on the low side with the compressor
running.

Dlhhedge814

I don't have that info as of yet have to hook up the guages and check it
once again. Thank you for the info.

Dlhhedge814

I've had the system serviced about 5 years ago and they told me they
changed the O-tube, maybe they handed me a line of BULL, think so? The
service manual m entions nothing about changing the O-tube, just gives a
general location.