Engine overheating...I think?

[marmaduke]

Hi all,

 

I was moving the boat this afternoon and the engine cut out following a lot of steam emanating from the bilge. It stopped as if it had run out of fuel and wouldn't start again for about 20 minutes. There's plenty of diesel so I don't think it's a fuel problem. She's running (stationary) fine now but I think she might have overheated. I hadn't been cruising long, maybe 1km. Any ideas what might have caused this and what I should check for?

 

Cheers,

 

M

[Bod]

Whats the engine?

 

 

Bod

[marmaduke]

Sorry, should have said, it's a BMC 1.5

[ditchcrawler]

what I should check for?

 

Cheers,

 

M

The cooling water level

[marmaduke]

I should also say, the steam (when running) all tends to come from one of two tubes that empty into some jars. I guess these are overflow from oil and water? Why would it be steaming from one of them?

[Bod]

What colour is the steam?

 

Bod

[alan_fincher]

If you really have steam coming out that can't be directly caused by a fuel problem.

 

The steam may be due to insufficient level in the cooling system - if your BMC has a header tank, then you should be able to see it at least part full even with the engine cold.

 

Or you may now have enough water, but still have an air lock somewhere that is preventing it circulating.

 

Do you have a temperature gauge, (many marinised BMCs even with simple control panels do). If so,how high does it normally go, and how high is it going when the steam occurs.

 

An engine that actually stops when overheating could lead to far more serious things, and may actually seize,so you need to be a bit cautios in what you try until you have resolved this. It is also possible you may now have a head gasket failed, I'm afraid.

 

[My spell checker wants to changed marinised engine to marinaded engine!]

[marmaduke]

Ah brilliant, thank you all for the advice. What would the gasket look like and where can I locate it? Would it be something visible to the eye?

[Dinz]

Skin tank or Raw water?

This may call for some popcorn & sit back.

End.

[zenataomm]

No you can't see the head gasket without removing the cylinder head.

As asked is the level of water in the top up tank visible?

Have you a working temp gauge, if so what was it showing?

 

Or is your cooling system a Raw one? Do you have to turn a tap on to allow it to suck in canal/river water?

If you watch your exhaust outlet does it normally have water coming out when it's running?

[bizzard]

I check that the thermostat is not knackered and stuck in the closed position first. Quite common, that. Overheating after 1 km would be about the right length of time for a lack of coolant or stuck thermostat to announce itself like that.

[ditchcrawler]

Or a hole in a lump of rubber hose

[RLWP]

I check that the thermostat is not knackered and stuck in the closed position first. Quite common, that. Overheating after 1 km would be about the right length of time for a lack of coolant or stuck thermostat to announce itself like that.

Or an air lock.

 

Has any work been done on the engine recently?

 

Richard

[alan_fincher]

Or a hole in a lump of rubber hose

 

Or a split in a Polar or Bowman "rubber" end cap on a header tank / heat exchanger.

[p6rob]

Or a broken fan belt

[matty40s]

you overheated due to build up of leaves on the prop and trying to keep going the same speed with more and more revs.(theory)

if you are lucky, you stopped in time and havn't knackered anything.

If you try again tomorrow, once you feel the boat sluggish, take the boat out of gear, have a quick blast of reverse, and then forward again.

You should find that you return to normal speed.

You may have to do this quite often at the moment.

You shouldn't overheat.

[bottle]

As per Matty's post.

 

I can hear/feel when the boat engine is working harder than normal and the wash out the back also changes (more splashing and going to one side).

 

Quick double blast in reverse, drift as far as possible, watch detritus leave the stern of the boat, engage tick-over speed for a few seconds then increase speed to normal .

[ditchcrawler]

BEFORE you even try to restart the engine check the water level is its a closed system, ie has a filler cap.

[Opener]

I'm with p6rob - "Or a broken fan belt" - I got an overhead warning after an early morning start recently - about 1km down the cut. Moored and checked over the engine bay. I've got a Barrus Shire with a skin tank. Half of the top hose was hot and the other/bottom hose barely warm but the skin tank was stone cold. "not overheating, then" I thought! Carried on gingerly after a short break and running the hot taps for a while. Faint 'no charge' warning buzzer so I moored up again and had another look suspecting my electrics had gone haywire.

 

Then I looked at the fanbelt. Most of it was still there visually but it turned out to be just the outside layer - the majority of the belt had disappeared (found it later on the floor!). So the water pump was not turning (overheat) nor was the alternator (no charge). About to call out RCR / resigned to sit on a mooring for a few hours when I remembered that the last owner must have changed the belt at some stage and had left the old one on board. Do you know how many potential storage places for a belt there are on a 50ft cruiser stern???! Found it / fitted it and, hey-presto, cooling and charging. (spent the rest of the day replacing everything turned out in the search!)

 

So have a careful look! I could see that my fanbelt was there but only on feeling it (for correct tension) did I realise that there was not enough left to actually turn the alternator/water pump.

 

...or it might be something totally different!!

Edited November 19, 2015 by Opener