Today I charged my ac a tad bit more since I was low, wasn't getting great cooling thru my vents. I've attached a picture to this post to show you my readings while AC compressor running. Looks like low side reads 42 PSI while the high side is reading just over 275 psi. Today was a 93°F day with about 35% humidity. Altho I noticed a slightly cooler vent temp it's just not reaching low 40s as i would expect. I plan on installing the heater-core bypass tonight when van cools down to eliminate any heat escaping the old blend door mixing with cold air.
also want to mention i used a pressure washer to blow cold water thru the condenser and radiator to help give it a juicy charge. These pressures on the guage were after the system heated back up and stabilized.

So all of this said, are my pressures in range? Seems like the low side is slightly low and the high side is slightly high. Could this be a slightly stuck closed TXV? what are your thoughts? Thanks in advance!

 

Both are a bit on the high side, indicating the system is overcharged. They should read around 35 and 220 at idle. Also, at idle I get around 50 at the center vents and it drops to 40 when driving, which is pretty normal.

 

What where the readings before you added Freon? Ambient temp effects pressure readings.

 

Before adding 134a my low side reading was at 19psi.

How is it overcharged? I charged the system based on the chart. It says for 90°-95° day the pressures should be at 45-55 on the low side and 250 - 300 on the high side. My system holds 3lb or more. so pretty large system.

I was parked at a car wash where the actual ambient air temp the fans were sucking was 95° F air. I don't challenge your answer, I am more curious about the actual reason the charts would indicate these readings but still be wrong. Can you elaborate? When I used water on the front grill, the pressures would drop to 30 on the low side and 150 on the high side. But when all the water dried out and the system heated back up, these were the readings. again this was at pure idle. No gas given. Just water to cool fins. Thanks for the replies.

 

Looks to me that your gauge readings are correct. But, if there is contamination in the system, be it moisture, or too much oil, performance will suffer.

Is the blend (temp) door properly adjusted? Are you getting good airflow thru the system?? If you van is a 97, and the blower motor hasn't been changed recently, I would not be at all surprised to find a bunch o' stuff clogging the evap core.

 

Brand new evap core, drier, blower motor, fan clutch and radiator. Compressor was done 2 years ago. just did the Dorman heater-core bypass hose this evening and it seems to help by 10+ -

It is currently 95° with humidity 40% and the max cool setting is yielding 59.8°F at its coldest from middle vent while driving 45mph. The vent temp at idle right now is 68°F and i am parked in a shaded area. Guess ill be sending it to a shop to have them do their magic to drain and refill.

 

Yes blend door is shut all the way and adjusted properly.

 

I would be tempted to have the system evac'ed, and recharged, just to eliminate a bad charge as the problem.

 

Was it evacuated after all the new parts were installed(prior to Freon) along with oil?

 

well - you are beating the 30 degree rule...just barley...

Here in south Florida, I havent checked mine in awhile but i do have dual AC and I think my is about 60-65 at idle and 50 running down the road...
this AC system does pull a lot of air...the intake is where the passenger feet are...it one of the biggest Ive even seen