2.4 poppet valve...

[Dave Estes]

While getting my block ready to rebuild after a Wiseco problem I noticed the poppet valve was stuck. I could not move it from bottom of the block while it was installed. I then removed it and the rubber seat came out withit. The rubber seat was melted to the poppet valve. Any ideas what could have caused this and a suggested alternative? I did notice my temp gauge was running a little higher than usual the day before. Help

[sosmerc]

There have been at least 3 or 4 different versions of poppet valves used on Merc V-6 Motors. They cannot always be interchanged....so be sure you rebuild with proper version for the serial group your block is in. Your engine must have been running without any water getting to the valve for it to have "melted"! As I understand their purpose, the valve keeps the block full of water at lower rpm. At around 1800 to 2200 RPM the water pump should develop sufficient pressure to open the valve thus allowing more water to flow through the block. A stuck valve will not permit enough cool water into the block. A valve that is stuck open will not cause a problem at high speed, but could actually cause overheating to upper cylinders at low rpm (especially if the water pump is marginal).