Steam exiting exhaust on D1-30 and running rough

[TonyMills]

Hi I can see steam coming out of the exhaust, together with water. The water didn't seem to be that hot? Coolant tank level is steady and the engine is getting hot, but I believe still within tolerance. The raw water system piping into the heat exchanger is clear pipe and I can see bubbles in the pipe work. No obvious raw water air leak sites. This has been going on for some time, since I completely replaced the heat exchanger and manifold in January 2025.

Since the heat exchanger replacement the engine has developed a hollow sound from the exhaust (not sure how else to describe it), steam is coming out, particularly at higher revs and it appears to be running rough (missing a little - do these engines miss?)

I've attached links to two short videos showing the bubbling pipes and the wet exhaust. The latter doesn't really show steam, the engine has to be running for a few minutes, with load and at over 2000 revs.

Bubbles Video Link
Wet exhaust video link

I'd appreciate any advice. Can the raw water side be bled?
Thanks
Tony

 

[Tranona]

The bubbles are not right. You probably have an air leak in the raw water system. First thing to check is the cap on the water strainer then all the hose clamps. Also check the water pump for wear.