Martin R

There are a couple of CAV 24V thermostats listed on eBay.

Would owners consider undertaking a Hull survey (thickness testing) when they have the boat lifted out for blacking. Either each time or every other. As we all know often the steel work goes unchecked until either an issue arises or the boat gets sold. Undertaking a Hull survey during this time would give you as an owner a overview of the steel work status.

Thanks for the advice, gasket material , well seal and Emery cloth all just arrived so I can clean everything up. I have back flush all the heads and blocks with water to ensure everything is clear, got some gunk out on the 1st unit but the 3rd unit where the restrictions where all clear.

I tend to use a bit of Stag on gaskets just to take up any unevenness on the faces. I hope there is no serious damage the cylinder and head did have flow but very restricted. I always turn the engine over with the spit cocks open and decompression off before starting and never had any water come out.

The outlet from the cylinder head was the same, the sealant plug moved to allow some water out.

Removed all the cooling rails, found the cylinder and head outlet pipes severely restricted with sealant

You are correct no water taken from the cut. System is fresh water filled with antifreeze, skin tank and open header tank

It is a closed loop fresh water cooling system, with the skin tank doing the fresh to canal heat exchange. I thought about head gasket, and guess I should get hold of one or two and strip that head that I said was getting hot first.

Evening, so the level rises due to overheat, it will slowly increase until it spews over. Slow the engine back down and the level drops. it has happened before and I thought it was down to me just pushing the old girl a little too much. the engine is direct with a skin tank. I suspect there is either blockages in the system or the system is in need of a good clean and overhaul.

So had to move the boat today, the header tank boiled over, I was not pushing the engine hard, so clearly I need to do some work

Thanks for the advice, I was going to renew the coolant over the winter so will check the diverter etc and attempt the inlet flanges.

Only just noticed, once I have moved to my new berth on Thursday I will be doing an engine flush and will check out the tappets.

In the photo it is the top coolant rail and first pipe after the rubber hose.

The unit furthest away from the water pump, the one that is hot is hot to touch and you would not leave your hand there for a considerable period, the other two are mush cooler, but all three cylinders casings feel the same. I would need to buy a compression tester to check those. The tappers I have not checked and need to dig out the manual. And i no longer have a IR Thermometer and really should invest in a new one.

Been running my engine today to double check the charging systems. What I noticed is that on the cooling water lines one cylinder was significantly hotter than the other two. The Cylinder blocks themselves all felt about the same, just the outlet pipe. I have put in some engine flush to see if there maybe a blockage, but anyone had a similar issue before.