Home › Forum › Ask A Member › 18-20-25 Fuel Diverter Cylinders run warmer? › Re: 18-20-25 Fuel Diverter Cylinders run warmer?
Water flows at all times through the exhaust cover and the top of the thermostat housing, and out the down tube at the back of the head. That route is not thermostat controlled, so that explains why your temp checks are all over the scale around the head. Only the cylinder jackets and bottom half of the thermostat housing and around the outside edges of the head are directly affected by the thermostat. Of course regardless of that, there is heat transfer through the metal parts which may be unpredictable.
You are going far beyond any temperature checks I’ve ever done. So this is educational to me. The highest tech I’ve ever done was the old heat check crayons, which were next to worthless.