Perkins 4107 engine overheating

[Forty_Two]

Good point, the exhaust hose is prone to internal collapse. It can look fine and be almost closed, but the lack of cooling water going overboard should tell you.

Indeed, unusually in my case the delamination was in a 1.25" water hose feeding the exhaust bend.

 

[bumblebeazy1]

Good idea!.... divide and rule! Also ensuring that the ejected sea water temp is as it should be. If it is OK then look for a problem on the engine coolant side or exchanger.
My only overheat problem with my 4108 was rust build up in an elbow reducing flow area by about 75% !

Was that the exhaust elbow?

 

[Iliade]

Add replace fan belt to your list. It drives the freshwater pump and can slip silently if worn, even if correctly tensioned.