Your 3000 GT hydraulic valves makes loud noise when the engine is cold why?

Loud noise from the hydraulic valves of your 3000 GT when the engine is cold is likely due to insufficient oil pressure or oil viscosity. Cold temperatures can cause the oil to thicken, leading to inadequate lubrication and increased noise as the hydraulic lifters struggle to operate properly. Additionally, if the hydraulic lifters are worn or malfunctioning, they may be slow to adjust until the engine warms up and oil circulation improves. Regular maintenance and ensuring the correct oil type can help mitigate this issue.