I just got the AC fixed...
when I start my 90 vet the engine clicks with a new sound(guessing its the AC compressor)
another thing, MY ENGINE HEATS UP BADLY!
Oil Pressure drops to about 30, and 20 when idling.
the Oil Temperature shoots to half the gauge reading when driving about 30 minutes..
the engine temperature is about 20 degrees from the overheating mark.

WHAT CAN I DO TO STOP THE OVERHEATING?

I love cruising around in my vette, its a beautiful feeling. Now that I have the AC, I dont have to worry about sweating, but now worry more about the engine overheating... I could only drive 30 minutes without freaking out.

I live in South Texas, ITS SCORCHING HOT and I unplugged the AC from the compressor to preserve engine live...

SOMEONE PLEASE HELP ME! I dont want my vette to die due to the AC and the heat!!

 

Post the actual temps observed. They may not be that bad. A new stock radiator or a DeWitts could be the answer so could a well cleaned old radiator with its fins combed straight.

10 PSI when at idle would be fine. 20 is no problem at all.

 

When i didnt have the AC, the pressure was at 75/80. now its at about 20/80, its a SIGNIFICANT DROP in pressure....
Is that suppost to happen?

The engine temp went at about 250/280 last time i drove it, and the oil temp was at about 60% of its gauge reading.(Royal Purple)

when I start the engine and it isnt running hot, i noticed significant loss of engine power!!
feels like the AC stole about 20 horses! I get no kick outta stepping on it anymore....

 

a/c would not affect your oil pressure , 70psi at idle is not normal, wayyy to high, you may have a restriction some where ,20/80 sounds much better, as far as engine temps- waaay to high, fan should kick in around 228-229 and when a/c is used both fans should be on. Opps saw you have a L-98 all betts are off.

 

Hard to say what's going on (I doubt the oil pressure is related), but if I had to guess this looks like someone dumped a bunch R134 on top of R12 or simply didn't know how to properly rebuild or charge the a/c. Coolant Temps should be lower with the a/c on as the fans are designed to keep the gas/liquid in the Condensor at around 100 degrees which is well below the thermostat (which is one of the reasons it needs one) and non a/c coolant fan operation (226 degrees main; 228 degrees secondary for a '90). You should scan to see the Coolant Temp Sensor and A/c fan switch signals to make sure the fans are coming on when they should be - which - for a/c would be somewhere around 200 to 228 psi and it'll make that, regardless of coolant temp, a couple of seconds after the compressor engages so the fans are going to be on sooner and keep cranking for a much longer time. You also need to know the a/c operating pressures which you're only going to get by hooking up a manifold gage set.

Noise when the compressor clutch engages is often caused by having too large of an air gap between the outer hub and the pulley. That can also create slippage and heat and sometimes a pretty rotten odor. Spec is .020 inch and with the a/c off, you can insert a feeler gage to see what it is. You'll have to get a shim kit - 12 Bucks or so for a handful of washers - and pull the the hub to get it right. Grab it with some oil filter wrench pliers or a strapon wrench and unbolt the 10 mm nut. Then gently pry off the hub with your hand underneath it to catch any shims that are all ready there. Re-shim until you get the .020 inch clearance. Torque the bolt to 10 ft/lbs and if you overdo it you'll crush the shims and be starting over.

Oil pressure idle spec is 4 to 19 psi and I'm betting someone, somehow moved some wiring around and got yours working right. These gages work by sending a voltage signal to a sensor which decreases in resistance as the pressure increases. The gage calculates/transposes the voltage drop to pressure. The change your seeing is probably because someone improved the connection or got the sensor working with the resistance it was designed to work with.

 

I don't mean to threadjack, but any insight as to where these shims can be found? I ran into trouble changing my clutch over and I took it to a local mechanic. All in all it couldn't be used and he couldn't find the shims for it, anyway.

 

Dealer - NAPA - try www.ackits.com -