pbsurf
Veteran Member
- Joined
- Jul 14, 2018
- Messages
- 46
- Location
- United States
- Vessel Name
- Inara
- Vessel Make
- Grand Banks 42 classic
Although the running operating temperatures are within reason at the thermostats, at the other end of the engines, the freeze plugs on the aft end of the cylinder head are at 225 when running at 1600 rpm. Using an infrared thermometer, below the thermostat, port is 170 and starboard is 152. The temps on the port side of block on the freeze plugs are port 150-155, starboard 130-142. The port engine overheated 3 years back and the cylinder head was removed,planed down, new valves, seats and guides replaced, mechanic apparently didn't drain engine as only 3 gallons of coolant was itemized, no thermostats. Mechanic did fit the improved neck in expansion tank for 7lb caps and coolant recovery kit. Engines are 6 cylinder, had 5600 hrs then and now are at 6200. Just replaced both engine raw water impellers. Port coolant removed, engine flushed with fresh till clear then give the drain an enema to get even more sediment out. Port HE removed, put in a bath, visually clean but not pressure tested, new coolant. Brian Smith, at AD, says there is likely sediment in back of the cylinder head that I can scoop out after removing the freeze plug. Want to talk to him a bit more about what the coolant passage is like and recommended tool. Anyone resolve cylinder head aft freeze plug heat before?