97 Deville cooling

The most common cause of this is that the air temperature control door (called a blend door) is stuck or the tiny electric drive motor that moves it is defective. You will need a good shop that fixes AC/Heater issues to diagnose this, I am just guessing based on past experiences with GM (Olds and Cady) cars. A picture of the little drive motor is below, the door it moves connects to the hole that has white.

First, you must have a properly installed thermostat that is working correctly. Second, Northstar engines are notorious for air in the cooling system after draining and refilling - keep checking the purge tank level after overheating and after the cooling system cools down. Third, make sure your cooling fans are working correctly (relay, fuse, temperature sensor) - check to make sure both are running when it overheats. If all the above is correct, the problem will probably be blockage in the system (try a flush) or your water pump itself is failing.

have you tried charging the ac system? most ac compressors have a pressure switch that will not allow the relay to engage the clutch if the coolant pressure is low. $15 can of r134a and maybe a $20 Haynes manual is well worth the price difference, eh?

If your low on freon then the A/C wont come on? for a 1996 you will need to get it serviced if you havent its normal to loose 10% freon a year,

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.
If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.
The hose goes in to the engine to a crossover and comes out the other side close to the thermostat housing,the blockage may be there.

need to replace the pressure sensor and fill up the gas 134 R or the filter gas is blocked , when is running the pipe are one hot and the others is cold be sure the vent fan is switch on

Sounds like the doors on the heater exchange are not working or are partially blocked.

I HAVE A 1998 CADILLAC DEVILLE,THE AC BLOWER MOTOR GETS HOT AND TURN OFF AND WONT TURN BACK ON UNTIL IT COOL OFF, WHAT IS THIS PROBLEM?

When the cool air ceases, does any air blow? If your air flow ceases (the cooling fans run the entire time the A/C runs normally), your cooling fans might also be malfunctioning. How many times has your car overheated since the September 2008 head gasket replacement? Repeated overheating will dramaticly shorten the lifespan of a head gasket (if you and/or your husband know your way around cars, the head gasket replacement isn't terribly difficult, just takes ALOT of time- you can send an email to maintjoseph @yahoo.com -no space between the name and the @ sign- and I'll help guide you through the head gasket replacement). I had to replace both gaskets and a head on my 1999 Taurus with a Vulcan engine and have had continuing problems with the cooling system. Your computer might also be acting up if you're noticing other driveablility problems.

Check fuses and lead wires to dampers.