A/C Gurus I need some help

[dan4010]

I'm having issues with my '93. just replaced the compressor about a month ago. When I drive the car in the morning, I have vent temps in the upper 30s, very comfortable. In the afternoon, during the heat of the day, vent temps are in the upper 50's which is not enough to keep the cabin cool in FL. Also, when I engage "auto" to start the A/C and begin cooling, the display indicates that both floor and upper vents are blowing with full fan. Is this normal in the Z32 when it senses its hot in the car? I've only known cars to blow out the upper vent when trying to cool and the lower vents when the heat is engaged. In the morning, when its cooler and I get the colder vent temps I mentioned earlier, only the upper vents are blowing, like I would think is normal. Pressures are good and its fully charged, no leaks. Vent temps don't vary much between idle and hwy speeds. Mechanic said I should think about replacing the expansion valve and condensor too. I'm looking for other possibilities. I don't want to spend $1400 to replace those until I've ruled out other less expensive possible solutions. Could it be the cabin temp sensor above my head? It's quiet, unlike in other threads where it was replaced because of bad bearings. Help. Thanks.

P.S. yes, I've searched and searched this forum.

[nissanfreak12]

Are you sure there is no air in the system, was it properly evacuated when they recharged the ac after replacing the compressor?

Is the electric fan actually turning on when the ac is on? How is airflow in the condensor/radiator, anything obstructing it, dirt, leaves, bird?

What the vents are doing is normal, because using both vents it blows cold air all over versus just high up. It is also very possible that your expansion valve and condensor may be clogged and not properly circulating the refrigerant. Why did you replace the compressor?

[NolimitZ32]

If the compressor went out on you its likely it got clogged from inside by trash in the system, if your accumulator/dryer and expansion valve werent replaced it is likely your new compressor wont last long either.

Oh and for 1400 you better tell your mechanic to sit on a down-pipe unless he is replacing with all Nissan parts because AMEM parts are considerably cheaper and there is not that much labor involved.

[nissanfreak12]

Totally missed replaced cause of bad bearings. Check for function of fan, air circulation, those are cheap and easy to check. If all those are good, what Nolimit said is gonna be the next thing to do.

[dan4010]

The compressor was replaced because of a leak in it. System was properly evacuated and cleaned out before recharge, and the dryer was replaced with the compressor. Electric fan runs fine. Out of curiosity, I took a look at the cabin temp sensor. The dumb a** that owned the car prior to me stuck a bolt in the fan to stop it from turning. Turns out it rattles like hell so I'll replace it. I Don't think that its gonna help my cause though. I spoke with Harry from Ztuner down here and he said that vent temps in the 50s is about the best I'll get out of a Z with FMIC in this part of FL during the heat of the day. Grrr.

[nissanfreak12]

That is ver possible cause the airflow is restricted, especially since you are probably running 134a vs r12, I know switching those two already makes the air warmer.

[es.biggs]

Sounds about normal to me. If your expansion valve was bad, the pressure readings would indicate it. Same with your condensor if it was blocked. The fins could be all smashed up causing a lack of airflow, but that's not really likely. If you get that condensor fan working, it should help out some. AC works amazingly well when its mild, and the hotter it gets (FL ain't no joke lol), the less effective it becomes. That's just the way it is