Hi All,
My Dad and I have tried many things to resolve our overheating Bukh but not having much luck.

The overheating has slowly increased over time to the point now where after only 5mins of running, the engine will get up to 100deg, prompting the alarm to go off. With the use of a temperature gun we've ascertained the back part of the block near the thermostat is noticeably hotter than the rest of the engine.

Things we've done:
- Checked impeller & volume of water exiting the engine
- Flushed / soaked cooling system with vinegar solution, Rydlyme and then moved to a hydrochloric acid mix
- Removed and cleaned the Y and adjoining hoses
- Replaced the exhaust elbow as we found a crack
- Removed and cleaned the exhaust manifold
- Bypassed the hot water system in case that was somehow the culprit

From what we gather next step may be taking off the head to check if there's a blockage we haven't managed to remove. This may be a bit beyond us.

Any advice at this point would be much appreciated.

Cheers,
Ed