Automotive Air Conditioning Information Forum

Dwight, You didn't mention the year, make, and model of the truck the A/C system came out of, or whether it called for R-134a refrigerant. Did the LT engine also come out of the truck? That will help us diagnose this.

For the moment, I'll take the liberty of "presuming" that this system uses a GM V ...

Thanks for clarifying.


I repeat the readings. When outside temp is around 72 F, car is not running and been sitting for at least 8 hours, pressure is around 73-74 psi on both sides.
So the static pressure is 73-74 PSI.


With car running, low side is around 28-29, and hight side 100-110 psi ...

In the video of your Manifold Gauge Set, it sounds to me like the engine is idling. If so, bump-up the engine speed to about 1,800 RPM, and retest the pressures. Otherwise, according to the Vintage Air specs, the system appears to be fully charged and operating normally.

R12 is not legal in my country so I cant búy it.
Okay...sounds like your car is a candidate for conversion to R-134a, if it's available.


I did check pressure in system this morning with engine on. It was 72 F and system pressure around 73-74. That indicates that I have enough refrigerant.
An ...

Does your car still have R-12 and a Sight Glass on top of the Receiver Dryer? If so, and you have on hand or can still purchase R-12 refrigerant, you can do it yourself the simple, old-fashioned way without a shop's intervention, presuming you have a Manifold Gauge Set (MGS) with the proper fittings ...

Tim, I've noticed no spam since June 29.

Part of the airflow restriction might have been the partially clogged cabin air filter. But if you suspect that the evaporator is icing-up, then it's most likely low on refrigerant.

As a first step, recover the R-1234yf, or have it done, and see how much refrigerant comes out. If the weight of the ...

Back in the days when the Dakota used R-12 refrigerant (1993 and earlier), the specs I have for that vehicle are 40 ounces net weight (2.5 pounds) of R-12, and 7.5 fluid ounces of Mineral Oil. I don't have any specs for the 1971 Scamp with the Slant Six.

With that being said, I'm not an A/C system ...

Nice vehicles, and the new logo looks great!

It certainly seems like the Blend Door Actuator is receiving a false signal. But before we go to the control module again, let's examine a few other things that you might be overlooking.

Seems simple, but have you checked the cabin air filter? A partially clogged or fully clogged filter sometimes ...