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MG MG Y Type - Water use

On a recent jaunt to Abingdon and back (a little over 100 miles round trip) the Y got through 6 litres of water.

By measuring before and after a standing period I am confident that it is not a static leak anywhere and the water only "disappears" on a run. It simply seems to boil away out of the overflow pipe.

It is possible that I am overfilling the radiator a little but a top-up of 3 litres after a 50 mile run does seem excessive. I start with the water level about 2.5" down from absolute maximum to allow for natural expansion as the water heats up.

A new water pump was fitted recently.

Thanks in advance for all the helpful suggestions that will be here in short order.

Murray
Murray

Could sound like a blown head gasket
Ole Aaen

Murray

If it is a blown head gasket you may find the following (in any combination):
* Oil film in water
* Water globules on dip stick
* Mayonaise forming in valve cover
* Steam from exhaust pipe after engine is at running temperature
* Lower engine performance as water doesnt burn as well as petrol/gas

It could also be a core plug so check those on the side of the engine for drips, or it could be a leak on the rear cylinder head end plate as these corrode through out of the line of normal sight.

Another thing to check is the engine drain tap and the radiator drain tap, that they are shut off and not leaking either through the tap or around it.

Finally also check all of your hose connections, especially those going to the bottom of the radiator for connection to the pipes. The T pipe piece there is made out of cheap metal and rusts away on the ends very easily so you could be getting high pressure steam leaking from there.

Also, overall condition of all hoses (including the short one to the block, and the big fat one to the radiator head, if they are old and brittle,they can become pourous and sweat.

Paul
Paul Barrow

Murray
Spread some newspaper under the front end and let her run till she gets really hot,increase the slow running screw if required then look for the tell tail drips and trace them back. This will also confirm if the water is boiling.
Peter
Peter Vielvoye

Thanks for your idea Peter. I did just that and found two things:
1. I confirmed that the only place water is coming from is the radiator overflow pipe.
2. I discovered a hitherto unknown oil leak from the side of the oil filter.

Paul, definitely no oil and water mixing and Peter's test showed no core plug or hose problems.

The water is simply boiling away. When I first acquired the car it was getting through water at a much higer rate and the radiator was flushed etc at that time but it seems that the cooling part of the cycle is simply too inefficient to cope with the heating part of the cycle.

Someone suggested removing the thermostat. Worth a try???

Open to your suggestions once more.
Thanks
Murray
Murray

Murray
Thr thermostat is built into the casting that holds it, if you remove it from the casting it is scrap. You can remove the casting then emerse it in water and bring it to the boil this will show if the thermostat is working (opening before the water boils at around about 75 degrees). If it does not open you have found your problem. NTG do a replacement kit including top hose but they will sell seperately.
Peter Vielvoye

Murray

Good news on the water.

It could be quite possible that the radiator has more sudge and rust in it now since it was flushed, so I would take all the hoses off again and flush the radiator and then back flush it too. Then I would flush and back flush the block.

Do both until you are getting nice clean water back out.

Then follow on with Peter's suggestions re checking the thermostat. If it is the original one, it may have failed.

Paul
Paul Barrow

This thread was discussed between 09/06/2009 and 15/06/2009

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