What causes high oil pressure on the engine of a 1996 GMC Suburban?

High oil pressure in a 1996 GMC Suburban can be caused by several factors, including a malfunctioning oil pressure relief valve, excessive viscosity of the oil due to low temperatures or incorrect oil type, or a clogged oil filter. Additionally, an oil pump that is operating at too high a pressure or an engine with excessive wear can also contribute to elevated oil pressure. It's crucial to diagnose the specific cause to prevent potential engine damage.