Hi im new to the site and had some questions about a 96 z28 i just got. after warming up oil pressure drops i know is normal, but when i turn on my ac it drops so low it has stalled my car and the low collent light usually comes on as well when ever i have the ac on. any pointers thanks

 

Could be the engine idle speed is dropping below normal when the AC is on, tis would cause lower oil pressure, and even stalling. The AC puts an additional load on the engine which if not adjusted for will cause the idle speed to drop. The PCM controls the idle speed valve to keep idle speed constant. Could be a bad IAC valve or the AC compressor is putting excessive load on the engine beyond what the IAC can correct. Too much refrigerant or the fans not going on high with the AC on will cause the compressor to work harder and put more load on the engine.
All of this should not affect the coolant level. Check the level with the engine is cold by removing the radiator cap. If the coolant recovery system is working properly the coolant should be all the way up to the overflow pipe. Also make sure the coolant level in the recovery reservoir is correct. If the coolant level in the radiator is low, and the level in the reservoir is good, then the recovery system is not working properly. Check for leaks in the reservoir, in the hose between the radiator an the reservoir, radiator cap, and anywhere in the cooling system. Could also be the level sensor is marginal.

 

It sounds like the engine rpm is dropping too much when you switch on the A/C. That could be due to a defective Idle Air Control valve (IAC). Is the SES lamp on? Does the tach stay relatively steady when this happens?

 

I don't have any lights or anything like that just the coolant light rpms move up and Dow a couple hundred while it is the stalling out prosses but that's it and seems to idle high its around 1000 1100 at its normal idle

 

So you have a high normal idle and stalling when the ac compressor kicks on. I would guess a small vacuum leak combined with a slow reacting IAC motor (AKA a lazy IAC)

I would start with cleaning the IAC and looking for the vacuum leak.

 

Thank you for all your info will try it all out and see what comes up and keep y'all posted thank you