Automotive Air Conditioning Information Forum

Once again I come here to the experts before I make more mistakes...

Long story short, I had a compressor that seemed to go out as I heard new belt squeal and it had difficulty turning. I flush the system using two quarts of flush and shop air, disconnecting the evap and cond and hoses and flushed them in the opposite direction of flow. Then I replace the compressor, a Sanden SD508, drain the oil out of the new compressor and fill the compressor with the correct amount of oil, replaced the receiver dryer, I pull a vacuum for an hour and it appears to hold it overnight.

Next day I attempt to start filling it. It takes the first can of 134a. Low side started to creep up and got to where it was below 30 pounds pressure while high side rose to about about 100. I start the second can of 134 and the low side dropped below 5 pounds, while high side stays at 100. It does not seem to suck any 134 in? I shut the engine and both sides equalize to about 50 pounds. Start engine again and I cannot get any 134 into the system. Yes, the valve on the low side of the gauge was opened.

I stop there. I am wondering if my orifice tube caught a piece of garbage and is blocking the system? Can this be taken apart and cleaned out? If so how does it come apart?

Or what else might be likely to cause the system not to accept the second can of refrigerant?



Thank you for your advice in advance!

If your orifice tube gets blocked with debris, it might cause problems with your system's capacity to take refrigerant. The orifice tube regulates refrigerant flow, and if it becomes blocked, it may block flow and cause poor performance. While the orifice tube can be removed and replaced, it is typically not advised that you clean it yourself because it can be difficult to fully clean and reinstall correctly. Instead, it is usually preferable to have a professional do it. Aside from a clogged orifice tube, the system may be unable to accept the second can of refrigerant due to a defective expansion valve, leaks in the system, or compressor problems.

What is the make, model, year, and engine size of your vehicle? Also, what does the posted photo show? It looks like a TXV, but I can't be sure.

Thank you for the replies. I was hoping I could fix it myself before seeking professional help. From experience, there are not many local professionals that want to touch an old Army truck.

JohnHere wrote: ↑Sat Sep 14, 2024 1:10 pm What is the make, model, year, and engine size of your vehicle? Also, what does the posted photo show? It looks like a TXV, but I can't be sure.

Actually, I have an aftermarket system that a prior owner installed into an old Army truck. That is picture of the evap connections that is installed. It is 24 volt system. It has a GM 6.2 diesel engine that originally did not have AC.

I found the exact evap that is currently installed: NO Ebay links allowed