a boating buddy has a problem...

2000 454 EFI in 22' Baja Hammer. Some time ago he sucked a horrible amount of sand and gunk into cooking system. Took weeks but finally got it out. Until the guink was out motor ran very hot.

Now motor runs VERY cold, 105 degrees, no matter what. He said he changed the t-stat already.

I recommended he install restrictor plate instead of thermostat to guage if this allowed engine to heat up, but promised to ask the guru's here...

Any thouhgts?

Backflush engine and oil cooler and put in a new thermo and temp sending unit. Ive been thru this once before.

Danb is right, temp sender can be hurt by high temps, it probably is no longer giving accurate readings, if you can, test with an infrared heat gun.