| | AC doesn't get cold until the engine fully warms up
Hi all, I'm having a really weird problem with my AC.
Immediately after I turn on the engine the AC will be cold and then it stops being cold after 20 or so seconds. It'll stay not cool until the engine fully heats up (you can see the temp drop several degrees from the thermostat opening) and then it'll suddenly start blowing cold air.
--The clutch electromagnet (OEM AC Delco) is only about 3-4 years old and it's not behaving like a weak coil, but I checked it to see it it was just too weak. During the time the air is lukewarm, the coil isn't even trying to engage as suggested by putting a screwdriver next to it. After the engine warms up, the clutch engages no problems. No slipping. And cycles just fine.
--Maybe a pressure sensor problem and the engine heating up warms the refrigerant lines to increase pressure enough to trip the sensor? Nope. Replaced both the high and low side sensors and nothing changed. OEM AC Delco parts.
--Refrigerant pressure is also normal.
When it starts working after the engine warms up, it's cold and stays cold. No problems. And if I turn the engine off and run a brief errand like a cup of coffee so that the engine is still hot when I get back, turn the engine back on and the AC is fine.
It's a '96 Chevy.