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'98 Chevy 1500 Orifice Tube Location - help please!

Discussion in 'General Chevy & GM Tech Questions' started by Texas Kid, May 12, 2011.

  1. Texas Kid

    Texas Kid New Member

    Hello GM Truck Club Forum:

    I'm hoping someone can help me with this. I bought an a/c kit and am replacing everything right now. I can't find the orifice tube... I've traced the high-pressure line all the way to the firewall, and am now looking under the dash. have the glove box off and am taking lots of little screws out of the housing that holds the evaporator... does anyone know, is it in there somewhere? Or, is there any chance there isn't one? I didn't see a place for it post condenser. Thanks! I'll check back in a little bit - going back out to the garage. Hope I don't break something!
  2. stephan

    stephan Rockstar 3 Years 5000 Posts

    By orifice tube I assume you're talking about the little filter that goes in the hp line, & not the expansion valve. The orifice/filter is usually installed in the metal part of the high press line where the hex nut joins the long part of the metal portion of the hose. All of these I've seen were where the line runs along the inner fender well. Just look for a "bulge" in the metal part of the line where there is a hex nut. Be sure & use a backup wrench on the other half to loosen & tighten it.
  3. Texas Kid

    Texas Kid New Member

    Found the OT!

    Stephen, thanks for your response. I'm not sure if understand it though.

    I did find the orifice tube after I looked for it again and again and again. Right next to the condenser, where the line exits, there is a place about 6 inches away where there's a connection. I disconnected the line right there and looked inside the line going toward the condenser and, whalah, there was the orifice tube. Guys at O'Reilly's told me it was behind the firewall... wrong! I had to take off the lower light assemble on the passenger side... but it was easy. Can't believe I spent 3 hours today trying to find that OT, and a lot of that time I was under the dash board. Glad I didn't break anything under there!

    I hope someone else finds this unformation useful. I looked everywhere and couldn't get a straight answer.
  4. stephan

    stephan Rockstar 3 Years 5000 Posts

    Glad you found it. Apparently the boys at O'Reilleys thought you were talking about the expansion valve & that's why they told you to look under the dash in the evaporator area. That's what made wonder which piece you were talking about, because you said you were looking in the evap area under the dash, & that's where the exp valve is, rather than the o tube.
  5. Texas Kid

    Texas Kid New Member

    Me and O'Reilly's guys were specifically taking about and saying "orifice tube" and not "expansion valve" so don't know why they would have thought I meant the later. Fact is, the two or three of them involved in the conversation didn't know and were guessing. They now know where the OT is located on a '98 GM 1500 truck, trust me.

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