air conditioning and overheating on 1997 Saturn SL1

When I drive my Saturn with the air conditioning on, it only runs with cool air when my foot is on the gas. When we are at a stop or idling in traffic, the air becomes warm. This has been going on for 2 months. Now the car has overheated as well, with white smoke coming out of the hood after being driven with the air cond. on for 30 + minutes. Can this be related? Can it be the compressor over working the engine or is it a pressure relay valve?

Asked by for the 1997 Saturn SL1
The air conditioning compressor defiantly puts load on the engine and takes away power resulting in losses in fuel economy as well. The additional load on the engine does increase engine running temperature. Before any other investigation check to see that the head gasket is not blown. This is best done by having a test done called a "block check' where the engine is run up to operating temperature and then the cooling system is checked for the presence of carbon monoxide (CO2) in the cooling system. CO2 is a by-product of combustion and is only in the cooling system if the cylinder head gasket is not seealing or the cylinder head is cracked. After these tests are done then investigate the air conditioning performance. The air conditioning has probably lost some of its refrigerant and needs to be topped up or more likely have the source of the leak found and repaired.
What if it's not leaking compression into the cooling sys directly? I would first start with belt tension,idler pulleys,oil on drive belt,causing slippage:etc;etc.Always start at the bottom & work up to major componentry.Rgds Arth