Loosing water from radiator

[martyn yates]

Went in a short drive this morning, before setting off the radiator was full about 1 inch from the overflow. On return the water was low and the core was almost exposed.
It's a standard 1968 saloon and is running very well, there are no obvious leaks and no water visible in the engine bay. There is also no water contamination when the rocker cover was removed. Please does any one have any ideas, I'm thinking head gasket, but the car is running really well and where is all that coolant going, no clouds of white smoke out the exhaust.
Any advice would be much appreciated

[svenedin]

It could be a hose that is perishing or has a loose clip. Perhaps it's a leak that only leaks when there is some pressure in the system when the engine is hot.

I'd refill with plain water and run the engine up to temperature whilst you stand there looking with a torch. I'm sure you will soon find the leak. You could also put some newspaper under the car (assuming it's in a garage) and see where the paper gets wet. I suggest plain water so that you don't waste antifreeze when it leaks!

Check the condition of the bypass hose. This is a small hose between the cylinder head and water pump at the front of the engine. It is a so and so to change.......

If you cannot find any leaks with the engine hot try operating the heater valve on and off (assuming it's the cable operated valve). They sometimes leak only in one position.

On modern cars I have used Ultraviolet fluorescent dye to trace coolant leaks but I don't think that should be necessary on a Minor. It's quite expensive and you need a UV torch.

Stephen

[martyn yates]

Thank Stephen
I will give that a try thank you

[svenedin]

Thank Stephen
I will give that a try thank you

You're welcome. I've expanded on what I originally said.

Stephen

[martyn yates]

Got the engine up to temperature with the radiator filled, no sign of any leaking hoses and no drips. Lost a lot of water again in a very short run. Let her cool down and refilled the rad, then spotted water running at the rear of the right side of the engine. At first I thought it was the heater control gasket, but alas no it coming from the rear of the head. Rocker cover off and a fair bit of contamination. Weirdly the car continues to run fine, but wil change the gasket tomorrow. Once again thanks for the suggestions, found it in the end.

[svenedin]

Got the engine up to temperature with the radiator filled, no sign of any leaking hoses and no drips. Lost a lot of water again in a very short run. Let her cool down and refilled the rad, then spotted water running at the rear of the right side of the engine. At first I thought it was the heater control gasket, but alas no it coming from the rear of the head. Rocker cover off and a fair bit of contamination. Weirdly the car continues to run fine, but wil change the gasket tomorrow. Once again thanks for the suggestions, found it in the end.

Good. Glad you found it and no harm done. Copper head gaskets are recommended and you will obviously need to clean up the mating surfaces of head and block. You may as well change the manifold gasket at the same time and it is worthwhile having a look at the tappet chest gaskets and cup washers as it is so much easier with the head off.

Stephen

[ManyMinors]

Bad luck. I don't think I've ever suffered from coolant loss from that area.