Countess - Engine cooling water pressure

[SmileyGiley]

Hi there all.,.. further to the cautious success. Here's some gen on the engine.

First day we had the boat I was running the engine & smelled a funny smell. Killed the engin & took a look around. Eventually noticed that the hose to the hot water doohicky from the engine had come off, dumping all the coolant in the bilges. Fair enough. Put the hose back on & tightened up the hose clip. Topped up the cooling water (yes - need to add antifreeze before winter comes) and carried on running. Eventually I noticed that a couple of the other hoses have tiny tiny leaks at the connections. Small amount but coming out under a fair amount of pressure. So... I think that there is a lot of pressure in the cooling water system, maybe too much.

Also noted that the first time I took off the cooling water filler cap there was a bit (not much, but some) of greasy emulsion on the filler. Not seen any since mind. Oil looks fine. So I'm wondering if the engine is blowing a bit into the cooling water thru a cracked head gasket.

Need to top up cooling water - maybe 1 - 2 litres per use. That's a lot

How can I tell if there's too much pressure? Any hints well accepted.

 

[misterg]

How can I tell if there's too much pressure? Any hints well accepted.

Don't you have a 'radiator' style cap somewhere? (Heat exchanger or header tank?) If it isn't 'blowing off' then the pressure isn't too high. If it is blowing off, then the presssure might be too high, but it's probably more likely that the cap has failed.

Unless it's a dinosaur of an engine, I would guess that the freshwater cooling system will be operating somewhere between 7 and 20 psi - that's quite a lot of pressure.

I believe you can get kits to test the cooling water for leakage from the cylinders, but have never seen or used one.

Have you had to top up since the incident with the loose hose? Maybe there was an air-lock during the initial refilling after the incident.

Do you have a calorifier?

Hope to see you around Conwy, etc.

Andy

 

[SmileyGiley]

Andy,

I think I did have an airlock after the initial incident... so although later I did have to top up on other occasions I didn't. A few times I have gone to top up & have needed little, other times I've been shocked by the amount needed.

So this could be one small leak that's intermittent - hose one way = leak, hose t'other no leak - but I just don't KNOW!

At the moment looking for ideas to check & test.

 

[oldharry]

Try running the engne p on fast idle with the filler cap off. If the gasket is blowing then you will get a white froth - a bit like detergent foam, or if it is bad you may actually see bubbles coming up. Engine needs to be warm. This is not a definitive test as an airlock can produce the same result. But no bubbles, the gasket is almost certainly OK.

Take care, because a badly blown gasket could blow the coolant out violently.

More likely from your description you need to sort those 'leaking hoses' - not unusally the spigot the hose attaches to is corroded or has muck on it so the rubber hose is not seating properly however tight the clips are. A few minutes cleaning each one up may solve the problem. A Misterg says, 7 - 20psi is a lot of pressure anyway, and the filler cap should be releasing any excess, taking coolant with it if there is a gasket fault.