Hello. I have a 5.7 Gi Volvo Penta, 2002. I recently put a heat exchanger/fresh water cooling system on the block since I run it in salt water.<br /><br />At higher rpm, the engine protection mode kicks in - alarm, auto reduction in rpm and speed. Runs fine at 3200 rpm and below. <br /><br />The engine ran at ~180 deg. both before and after I installed the heat exchanger. This is slightly higher than the manual recommends - range of 155-175. I have tested the thermostat that came with the heat exchanger and the original one on the boat. Both open at 160 deg.<br /><br />The boat has sensors on the exhaust elbow and the adapter pipe that goes into the intake manifold into the coolant chamber.<br /><br />The boat has under 100hr on the engine, so I guess it could be the impeller - but physical inpection does not show any real problem.<br /><br />Any ideas?
