Morris Minor Owners Club

To the rear of the cylinder head on the main engine block there is a tap. And there are two pipes connected to the tap body that come from the interior heater presumebly this tap is to bypass the interior heater. So if I turn this tap off I take it the water will still be circulating around the engine block and will I have to do something to the hoses that come from the heater or just leave them alone. ( The hoses are still connected obviously )

Very unusual arrangment by the sound of things ! Any chance of a picture? Normally only ONE pipe on the tap - the return from the heater goes along a wee cooper pipe and eventually into the radiator return pipe. The normal deal is that you open the tap to circulate water through the heater - and in fact it's best left open all year round!

That sounds odd. Do you also have the usual heater tap on the cylinder head?

yes your probably right it's the tap too stop the water circulating through the heater, there is one pipe from the heater to the one side of the tap and the other pipe from the heater goes to the long copper pipe that joins to the other water pipe at the front of the engine. surely if it's there to bypass the heater then it couldn't do any damage if it was turned off otherwise why would they put it on the car, the mind boggles. sorry I can't put any pic's on as I haven't yet mastered the art.

'cos water circulating through the heater stops it silting up and decaying - to some extent, anyway.

Oh, so there isn't really two pipes on the tap and it's on the head not the block? That's normal. It doesn't bypass the heater, it stops the water going through it so the inside of the car doesn't get as hot in the summer.

I presume you want to close it because the heater matrix is leaking ? You would also need to block the 'return' pipe in that case.

bmcecosse wrote:I presume you want to close it because the heater matrix is leaking ? You would also need to block the 'return' pipe in that case.

If that is the case, a quick bodge is to run one of the hoses from the tap to the return pipe and close the tap. I did a few thousand miles like that before I bought a replacement matrix.

Indeed that will work well - but better to keep the tap open and circulate water round the back of the head/block.

Thanks for all your replies, I really wanted to block the heater off as it gets rather warm inside the car during the summer, so while i've got it garaged till the spring I would do it anyway as you say it would be better to leave it with the water circulating to stop the matrix getting clogged so i'll just pop back into the garage and turn the tap back on, I'll hve to get used to driving with the window down or in swimming trunks Thanks again,
mungo

The idea is to shut it on hot days - that's not often - and on such a day your engine will appreciate that extra circulation anyway !! But if you shut the flap - very little hot air should come into the car anyway.