new compressor new dryer, an expansion valve went from r12 to 134 with the poa update valve system cools for a few min the the head pressure goes up an shuts the compressor off some say i should put a fan on the front side of the car to cool could this be the problem?
What are the pressures at 1500rpm, Max AC, High blower with the doors open? Knowing that can help quite a lot. Does the head pressure go up at idle or driving down the road. If at idle, there certainly could be airflow issues with the condenser. The most common cause is a weak fan clutch. While a fan can work, misting the condenser with water from a garden hose while watching the High Side pressure can tell you a lot. If the High Side pressure drops like a rock, the fan clutch is weak or there is a lot of debris between the condenser and radiator. Hope this helps
I agree with knowing the actual pressure on the high side. It is possible that a defective switch may be prematurely opening at a lower pressure than designed. It is also possible for a missing radiator shroud to affect cooling of the condensor. Something else causing the problem is a radiator running hotter than normal, having a deleterious effect on condensor cooling. With respect to the fan clutch, two things. How close to the radiator is the actual clutch? Does the fan freewheel? You should notice, as the air reaching the clutch starts to really heat up, the fan should start to "roar," especially at fast idle. Is this an issue that just started?
"poa update valve system" This says it all. You guys missed it. It is working as it is supposed to, cycling the clutch (which was never designed to be cycled, by the way). Good luck.
