Orifice tube location

[abunaione]

Haven't been around for a while.
Haven't really had any problems.
2000, Chevy, K3500, SL, 7.4L.
Have a question about the orifice tube location.
It is located at the outlet of the condenser.
As the liquid turns into gas, it has to go through a tube almost 4 feet before getting to the evaporator.
Seems like it waste lost of cooling going through the tube.
Maybe it doesn't make a difference?????
It would seem like it would be better if it were at the inlet of the evaporator.

[Cornbinder89]

I tend to agree, but GM doesn't. I notice it is insulated but it is still on the low pressure side of things.
Having said that, I don't think much of orifice tube systems in automotive in general, they are fine in refrigerators and such where the compressor speed is constant and the load easy to compute.

[Tom Greenleaf]

I think auto makers design for the fastest assembly time new more than that. If it was faster and cheaper it would be changed.

Older than this look/think how long the line was to REAR EVAP in Suburbans + vans were TXV for those did work OK just stay liquid till it gets there,

[abunaione]

Orifice tube is a cheap compromise. Never did work as good as the expansion valve.

[Tom Greenleaf]

Does the A/C work well in this truck? I own this in a 1997, std cab (smaller area granted than most cabs) is great, all OE parts lasted so far just shaft leaks over winters - for outdoor vehicles with age seal and shaft don't like zero F. is normal here.

It seems to be THE issue that or whole other vehicles no oil evidence behind clutch it's too cold to even cycle on - pressure would be too low anyway.

That's a Vortec 5.7, compressor up top where it should be next vintage put that lowest on its own belt (the 5.3) is subject to choking on oil if over oiled.

GM isn't alone at obvious mistakes IMO not just A/C stuff other bull too as if nobody looked at a prototype before sending a style/shape off to a decade or more of production expected - sink or swim if these don't sell new it costs a fortune to design things to be defrayed over zillions of units or lose market share.

Dang trucks are shockingly costly new a base work only version history now once a bargain vehicle if that's all you wanted - cheap and it runs, easy care routine things plus handy for some,

[Cornbinder89]

Orifice tube is a cheap compromise. Never did work as good as the expansion valve.

Orifice tubes have their place, but automotive A/C isn't one, in my opinion. Window A/C, 'fridge and deep freeze in your house likely are all orifice tube systems, and they work well in those application.
I think the systems designed and used in the late 60's early 70's were the zenith of automotive A/C design. Not the most efficient, but the best at what they do.
Automotive A/C is a tough operating environment, everything is in constant flux, from heat load to compressor speed. to temp fluxuations outside. It is difficult to design a system that can handle it all and still work well.
By the mid 60's the mfg got serious about it and came up with some good systems, by the mid 70's Cafe fuel consumption ratings became more important than A/C and it suffered.
With the new trend in electric and hybrid cars, electric compressors may change the system design again.
Three phase variable frequency, A/C units are already in home use and in some cars. Being able to control compressor speed (and output) to match the heat load opens new possibilities. It will make engine driven compressors obsolete.
Gone are the days of simple pressure switches and Tx valve systems. Tx may stich around for awhile, but gone are the days of "jumping" switches to start a system, for better or worse.