How do you flush the ac unit on a 1996 cadillac deville?

You can't simply "flush" an AC system on a 1996 Cadillac DeVille (or any car) in the way you might flush a radiator. The AC system is a sealed system containing refrigerant, oil, and potentially other components that are harmful if mishandled. Attempting a home flush is extremely dangerous and likely to damage the system beyond repair.

Instead of flushing, if you're experiencing AC problems, you need a professional AC service. Here's what a professional will do:

* Recovery and Recycling of Refrigerant: The refrigerant (R-134a in most 1996 Cadillacs) must be carefully removed and recycled using specialized equipment. Releasing refrigerant into the atmosphere is illegal and harmful to the environment.

* System Inspection: The technician will inspect the entire system for leaks, damaged components (compressor, condenser, evaporator, expansion valve, etc.), and blockages. This often involves using specialized leak detection dyes and equipment.

* Repair or Replacement of Faulty Components: If leaks or damaged parts are found, they will be repaired or replaced.

* Evacuation: After repairs, the system will be thoroughly evacuated to remove any remaining air, moisture, or contaminants. Moisture is particularly damaging to AC systems.

* Charging with Refrigerant and Oil: The correct amount of refrigerant and oil (PAG oil is common in R-134a systems) will be added based on the system's specifications.

* System Testing: The technician will test the system to ensure proper operation and cooling capacity.

In short: Don't try to flush your AC system yourself. Take it to a qualified automotive AC technician. The cost of professional service is far less than the cost of a damaged compressor or other components caused by improper DIY attempts. This is a specialized task requiring the right tools, knowledge, and safety precautions.