Hi, I am trying to help a friend who has just bought a narrow boat with the above engine, not sure yet which model, I will add when I get the info. I believe he,s used it a couple of times pottering round with no problem. Now it is overheating within minutes and he has shut it down immediately. I have seen a valve with red lever which is closed, should this be open when adding coolant? Should we try running with pressure cap removed. Does anybody know a diesel mechanic within travelling distance of Preston Brook? I am going to have a look today and hopefully have more info and pictures. If anybody could give advice as best starting point, I,m ok with cars, tools, electrics etc. I,m just rying to help him and save him from getting stung. Many thanks in advance to anybody who has the time to reply. Just received this image. The valve I was wondering about is at the top of the picture.