What is the purpose, and what is the proper location of the orifice tube in the air conditioning system on my 1991 chevy silverado?

The orifice tube is inside the tubing of the A/C. Most likely in the bottom tube that comes out of the firewall.

for step by step details with location and diagrams click the link below:

https://fexya.blogspot.com/2021/06/orifice-tube-location-on-91-chevy.html

this will help.Thanks.

The orifice tube is located in the line of the high pressure side of the system it maybe at the condenser or in the high pressure line. You should be able to feel a crimp in the line and the is the stop for the orifice. I believe the o6 is in the line and as I said there is a crimp in the line where the orifice is located.

best advice is the method i would use to located the orifice tube in the 2000 chevy venture. check the automotive repair book section in your local library. Most libraries have repair manuals on their automotive shelf section. find the a/c manual for your year and model car. make a copy of the page that has the information you need. you will need to make a copy because the library will not let those manuals be checked out. you might want to google for the location of the orifice tube location. I hope this helps.

ORIFICE TUBE AND LOCATION IN VEHICLE

If you are not somewhat mechanically inclined you should let a professional do this as the AC coolant will be released. You will have to re-charge the system upon completion. Here are some quotes from on-line mechanics to give you a better idea what you are looking for. The Orifice tube can be determined as faulty when your AC doesn\'t cool properly in the summer or heat well in the winter. Often you will smell antifreeze inside your car\'s interior.



"It\'s buried pretty good. It\'s in the liquid line that runs along the left inner fender well, under the brake booster. If you look closely at the line, you will see a connection and dimples in the line where the tube is located." Quote from ASE: Wrenchtech Aug 2011.

The liquid line is located in the area of the abs pump.

"The fixed orifice is located in the inlet tube to the evaporator core, this is where the small high pressure AC line from the compressor connects to the tube sticking out of the engine firewall, u will most likely need a special tool to remove it," below is an example of the tool, "don\'t damage the evaporator core by trying to remove the orifice tube without this if it is stuck down in the tube." ---Dennis Weid

The tool comes as a single apparatus or you can get the kit. Here are some examples of manufacturers who make these parts. I have removed the sales information because there are literally hundreds of choices out there including your local parts stores:



Mastercool 92311 Deluxe Orifice Tube Repair Kit This 5 piece universal kit will remove and install any style orifice tube.



Another suggestion comes from Ronnie Bennett Sr.: "The orifice tube will be on the small line joining the evaporator, the ac line will be swelled where the orifice tube is at, you may not see it, but use needle nose pliers to remove it, and to install it."



But I would look at YouTube for a better understanding of what you are looking for, how it works and how to remove and replace it, so try this site to start with and look further. You\'ll be surprised the amount of data available and a video is worth a zillion words.

https://www.youtube.com/watch?v=ae3zQQOhkDY

Dennis

If you haven\'t seen pictures of the part, this is what it looks like:

You have a flow restriction,the orifice tube,(inline filter) on the low side(suction)a/c hose.Check close by the dryer and lines for freezing over,if so evacuate,then flush a/c system,install new orifice tube and recharge with new oil and freon.

The orifice tube is inside the tubing of the A/C. Most likely in the bottom tube that comes out of the firewall.

It is located inside the condensor tube running to the evaporator.

Here are the removal/installation instructions as per alldata:

TOOLS REQUIRED

J 39400-A Halogen Leak Detector
J 26549-E Orifice Tube Remover

REMOVAL PROCEDURE
-Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
-Remove the air cleaner assembly.
-Remove the vacuum brake booster.
-Remove the condenser tube.
-Use J 26549-E in order to remove the expansion orifice tube. IMPORTANT: DO NOT use any solvents or chemicals to clean the porous plastic inlet filter of the expansion orifice tube.
-Inspect the expansion orifice tube for the following conditions and clean or replace with a new tube as indicated:
-Broken plastic frame (1); replace the tube.
Inlet filter (3) damaged or plugged with fine gritty material; replace the tube.
Inlet filter (3) coated with metal chips, flakes, or slivers; remove the coating with low pressure shop air ONLY and reuse if the filter is cleaned satisfactorily. Do NOT reuse the O-ring seals (2).

INSTALLATION PROCEDURE

IMPORTANT: Lubricate the new O-ring seals (2) with mineral base 525 viscosity refrigerant oil.
If you reuse the orifice tube, install new O-ring seals (2).
Carefully grasp the edge of the expansion orifice tube (1) without touching the inlet filter (3) and insert the expansion tube into the condenser tube until fully seated.
-Install the condenser tube.
-Install the vacuum brake booster.
-Install the air cleaner assembly.
-Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging.
-Leak test the fittings of the component using J 39400-A.

You will need to check with a/c gauges, most of the time when a/c line frost is a sign of low on freon.

on pass side underhood you will see reciever/drier(large line goes to it,Then you will see small ac line by it,disconnect small line, orfice tube is inside it.

FREON ENTERING THE EVAPORATOR WILL SOUND LIKE AN AIR LEAK. THE ORIFICE CAN SOUND LIKE ITS HISSING.

HAVE A SERVICE CENTER CHECK THE ORIFICE TUBE, MAY NOT BE INSTALLED PROPERLY.