Thanks Ewalt98... I hear about all these people with upper 30's and lower 40's and have never been able to get mine to that.. I did see upper 40's once or twice when the conditions were perfect like slight rain and 75F outside or very first thing in the morning before the sun got the van hot...
Many others say 50's is good for a van as there is so much insulated space.
Our same compressor and almost the same evaporator, and condenser is used in a truck with 1/4th the space to cool...
Either way you are right,,, 50's is great in the front of the van! Towards the evenings I have had to turn my fan down..


That average 54 is day and night average.. On a hot sunny day 96 degree day I only see the upper 50's when moving and lower 60's if sitting in heavy traffic..

 

My nephew and I replaced everything except the lines and evaporator a year ago. With a recent week of 90 degree temperatures I fed the sensor of an electronic thermometer about 8-10 inches down the center vent. After about 20 minutes on the hiway the thermometer indicated 4.6C. That's 40 degrees Fahrenheit! A dual evap system called for 62oz of 134a for a full charge. I believe that's the key to cold air. Measure your charge by weight and not the gauges We fed it 4 full cans and only had to measure the last few ounces from can 5.

 

Thanks for the advice Jeffrey. I changed every part on mine because the lines had rust inside them...
Mine calls for 56 ounces of R12.. I used 4, 14 ounce cans which should have been 56 ounces.. I learned later that it is better to weigh the cans because some may not have a full 14 ounces in them... On top of that I lost a bit more when I removed the high side gauge line... Those two things along with the front compressor seal leaking, I don't know how much is left in the system.. The front seal leak is very small because it is not wet looking, it is just collecting dust behind the pulley...

Below is a short video where I hooked up the gauges a few weeks ago just to check what it is doing. I believe it is cycling a little fast but that is because the RPM's are supposed to be at 1,100 and I think it might be a little fast since I don't have a tach..

But if you look at the blue gauge,,, the center red scale is for R12 and is supposed to indicate the evaporator temperature. According to my gauges the evaporator temperature is about 24F when the cycle switch cuts out and 48F when the compressor kicks back in. So that means the average evaporator temperature should be around 36F.. That is if I am understanding the gauges correctly...

Torky2 over in the HVAC forum suggested I have a air leak somewhere. Blend door or fresh air vent. He said it doesn't take much heat from the engine compartment to raise the temp... My 88 does not have a heater valve on the either of the heater lines so it has flow all the time. My manual doesn't show one either..

Anyway here is the upside down gauge readings..

Well interesting, it says the video is the wrong format to post it.. Ill try later..

Well I just added a pic and it went to the top of the page.. The video was a MP4