* PCV Valve (Positive Crankcase Ventilation): The PCV valve on this engine is typically located on the valve cover. It's a small, usually plastic, valve with a hose connected to it. It's relatively easy to access and replace; you'll likely need to disconnect a hose or two.
* EGR Valve (Exhaust Gas Recirculation): The EGR valve is usually mounted on the intake manifold. It's a bit more difficult to access than the PCV valve, often requiring removal of some heat shields or other components to reach it easily. You'll probably need to disconnect vacuum lines and possibly electrical connectors.
Difficulty of Replacement:
Replacing the PCV valve is generally considered a relatively easy job for someone with basic mechanical skills. It's a straightforward swap.
Replacing the EGR valve is more involved and could be considered moderately difficult, depending on your experience and the condition of the engine bay. While not extraordinarily complex, it requires more time, potentially some specialized tools (sockets, wrenches, maybe a vacuum pump to test the valve), and a bit more dexterity to work in a tighter space.
Recommendation: Before attempting either repair, consult a repair manual specific to your 1993 Cadillac DeVille 4.9L. A Haynes or Chilton manual will provide detailed diagrams and instructions, making the process significantly easier and less frustrating. These manuals also often show you exactly where the parts are located on your specific engine. You should also visually inspect your engine bay to get a feel for access before starting.
