WhiteChevy3

this is correct^^
Pressure - Temperature Chart for HFC-134a

theres a PT chart. you probally need around 40lbs reading on the low side. 40ish degrees coming out the vents..

1FastBrick

iTrader: (17)

You won't get the full 12 OZ out of each can. As mentioned you should get vent temps in the low 40's.

Those small cans add oil as well as refrigerant. Some even contain Silicon so you need to be carefull.

I am not sure how much oil you put in the system already so I can say for sure how much you need to add. GM has specs on how much to add for each component you replace. Do NOT go over as it can affect cooling performance.

Same with the refrigerant. Those bottles are not accurate. I would get a 3rd can and add a little at a time monitoring the pressures as well as the temp so see if it drops. as mentioned bring the engine up to 1500- 2000 RPM.

On a gas set up I go to 2000 RPM.

thunder550

iTrader: (70)

It is the diesel that I'm working on. That PT chart looks way different than the other ones I've seen, is it for automotive?

thunder550

iTrader: (70)

I didn't add much oil, if I had to guess I'd say an ounce or so. It didn't take much to fill up the yellow hose. I have a 3rd bottle of refrigerant, I'll start adding some of that tomorrow. Thanks

1FastBrick

iTrader: (17)

I prefer a chart like the one below that gives you high and low PSI. I personally don't do any AC work under 70* outside. It can affect your readings. Temp not only affects the refrigerant but also the gauges and valves you're using to fill the system. In some cases I have seen the lower outside temps give false readings and make it seem like the system is very efficient only to have the customer return on a hot day saying its not cold enough.

IDQ - Auto A/C Products & Sealing Solutions

1FastBrick

iTrader: (17)

Another thing to keep in mind is the new oil added to the system may have gone directly into the condenser affecting cooling efficiency. But I can almost assure you that you need more refrigerant. As I stated earlier you don't get the full 12 OZ out of those cans. Especially as the pressure equalizes in the system. You also lose whatever small amount is in the yellow hose between the valve on the can and the gauge's.

This is why I prefer the larger 30Lb bottles with a scale.

thunder550

iTrader: (70)

Thanks for the info, and the low/high chart. I'm guessing this means I need to replace the orifice tube? 1500 RPM, 70 degrees ambient. Low side is right where it should be, high side is really high according to your chart.




And I have to ask since I'm an a/c noob...these are the correct hookups, right?



Here's the pressures with the engine off and equalized.

1FastBrick

iTrader: (17)

Those have an orifice valve as you mentioned.

It looks like a small filter with a little bypass valve.

2001-2006 Chevrolet Silverado 2500 HD A/C Orifice Tube 4-Seasons, OE replacement

Probably should have done that with the Dyer but alwell.

We used to do it for Warranty purposes when we replaced a compressor, dryer, or condenser. You will be amazed how dirty is when you pull it out.

1FastBrick

iTrader: (17)

Oh, and yes those are the correct hook up spots. High and low are physically not interchangeable.

thunder550

iTrader: (70)

Cool, I'll get a new one tomorrow hopefully. Should have changed it but oh well...all its gonna cost me is 2 cans of refrigerant and another hour and a half or so.

As for the low and high connections, I just wanted to be sure, most of the sites I looked at said the low side would be on the suction side of the compressor and the high side would be on the discharge side. Obviously this is different.