Scotty i have an 1993 Ford F150 4.9 I6 5 speed Standard, the thermostat went out on me & caused the truck to get hot, i took out the thermostat filled it up with water & that was that, now i hear like a rattling nosie coming coming from the engine but ONLY WHEN THE CLUTCH IS NOT PRESSED IN i push in the clutch & it goes away, please help could it be something with the transmission it’s just weird it would do this literally after i took the thermostat out & filled it with water, btw i have great oil pressure
Throw out bearing. ASAP, replace the water with 50/50 coolant.
I think if it's making noise when the clutch is NOT pressed in, it's the pilot bearing in the flywheel. As @doc says don't run just water in your cooling system, put in 50/50 antifreeze to protect against corrosion. Also install a new thermostat.
