Ther was a knocking noise intermitantly coming from the engine and when I stopped and checked the engine was very hot and the fan was running although I had only been travelling at low speed for about 4 miles.

I saw that there was no water showing in the resevoir and the top was askew and not srewed down properly. I let the engine cool for an hour and then refilled with water which took about 4 pints.

The engine started ok and then i drove gently for a mile and stopped to check the level and had to add a little more. I repeated this procedure another 3 times in the 3 miles it took me to get home and I estimate I added about another1 pint. The engine seemed to run fine with no noises.

The car is now parked for the night.

Any ideas what might have happened, what damage might have been caused and what I should do or avoid doing now please?

possibly your thermostat

I've been to my local garage this morning and the mechanic tested the system by putting some dark blue liqiud into a two part glass tube with a rubber squeezer globe on the top. He put this into the header tank and kept squeezing and releasing the bulb and air bubbles were going up into the glass tubes each time. He then did the same after he had run the engine for a couple of minutes on higher revs.

He then compared the colour of the liquid in the tubes with the original dark blue colour in it's bottle and it had become more of a dark green, which he said indicated a little gas getting into the cooling system and likely a small head gasket leak. I am to monitor the coolant level closely and if it continues to lose water I will need a new head gasket, but if it doesn't lose any more it should not damage the engine.

Could the fact that the header tank cap had not been screwed on properly have caused the original huge water loss?

Is there any way of fitting a temperature gauge to these models?

I'd get the head gasket done otherwise it will probably go at some point and possibly crack the head (ouch). If header tanks cap wasn't on properly it maybe what caused to gasket to go.


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A common cause for loosing coolant is the head gasket leaking.   Have a look at the oil filler cap.   If it is covered in a greyish goo then the gasket is definitely leaking.   If so get the gasket sorted before it does some serious damage.

You may get lucky and it will just be the gasket. More often than not there is something else gone wrong too. It's not that common for these gaskets to just "go". Hopefully you haven't got a warped head, which would require being sent off and machined flat again.