isuzu 3LD1 marine diesel overheating

[berniekatchor]

3LD1 INDUSTRIAL ENGINE WITH HEATEXCHANGER OVERHEATS

Here is a 75 year old foolish single hander stuck in Malaysia
Welded a crack in exhaust refitterd and engine overheated. I am sure this is irrelevant
WEnt thro all processes finally inserting new fresh water pump and headgasket cleaned thouroughly heat exchanger. raw and fresh water flowing
water seems to flow thro block when head was off
could block have blockage Malaysian mechanic says impossible

BUT SAME PROBLEM 15 minutes at idle 1500 rpm overheat

all Malaysian mechanics say never seen before BUT someone must have an idea PLEASE

[berniekatchor]

hey ran diesel 3500 rpm 2 minutes and all ok
Was an airlock which 1500 rpm did not fix pity I spent $2500 on failing expertise

thanks to all

[Lepke]

I don't know your engine, but probably your thermostat was fully closed and not allowing water to completely flood the engine on refilling. 3500 rpm warmed the block. Some thermostats come with a small hole so air can escape. Large diesels usually have a small bypass allowing some circulation before the temperature rises enough to open the thermostat. The solution is to drill the small hole.