I feel quite frustrated at the disappearance of the water in the radiator of my 1937 Mk. 2 Pearl. There does not appear to be any leaks; just to be on the safe side I added a can of Radweld. The hoses are not leaking, nor is there any contamination in the oil. So can anyone suggest where 2 pints of water is disappearing every dozen miles or so?
Peter

Has it got a blow off valve? If so, has the spring collapsed?

If not, hate to think!

Regards, Stuart

Is the loss cumulative? would it empty if you did not fill it up ? The reason I ask is that if you fill the radiator up to the very top it will always rid itself of about two pints ,then settle. giving you the impression that it is "using" water. mac

There is no blow off valve in the radiator! Also the loss does seem to be cumlative. If I don't add water she quickly boils. Usually I do now fill almost to the top because of the loss, but the radiator header tank is dry after 12 or so miles!
Peter

Peter,
One possibilty is it is leaking into one of the cylinders and being expelled with the exhaust.

Another is that it disappearing down the overflow. I recently had a similar problem caused by a tiny hole in the cylinder - every so often a mass of bubbles would be released into the header tank increasing the level of the water until it flowed out of the overflow. The problem was only apparent some times and when the engine was hot.
Dave Griffith

I would go along with Macs idea.
Mine cannot be filled right up, if you do it will spit it out until you can just see it in the bottom of the header tank, and that is how it stays
.
I used to top up after every run thinking it was losing water, now I dont bother!

Steve.

Peter, it does sound like head gasket in your case. You might be able to rig up a pressure setup & pump a few pounds of air pressure into the cooling system & see if the pressure drops over time. Then chase the "leak", starting with cylinders. Tip: Add colouring to the water (either strong green glycol or food colouring), then take a "swab" out of each cylinder through the spark plug hole and look for the colour.

The subject of "natural" water use was done to death in Feb 06 (14th) - see the "More on water levels" thread.

Cheers,
DG

Motor factors these days will sell you a kit with which you can tell whether 'products of combustion' are getting into your cooling water when a sample taken from your radiator water changes colour ( or not ! )after the addition of a reagent. A little expensive but a very quick way of telling whether your gasket is leaking or not.

I agree that too much water will just be dumped out try filling up about 1" above the bottom of the tank start the car leave on a fast tickover on the drive for at least 20 mins have a cup of tea and watch what happens leave the cap off the rad so you can see the water level if it stays put you have no problem if it goes chances are the head gasket has gone.

Chris

If you can just touch the water with the end of an index finger poked through the filler neck, then the level is about right. Works on most thermo-syphon systems, no matter what the car.

Remember, when the water level drops below the top of the rad core, the thermo-syphon system ceases to operate. Disaster follows.

STEVE

Steve,

You opined as follows ............

"when the water level drops below the top of the rad core, the thermo-syphon system ceases to operate."

Is this 'strictly' true? It would still have a small head at this particular point. Surely the engine would still be making heat and pushing hot water up the top hose for a bit longer. Unless you know something I don't know.

It is in any case I am being a pedant, and indeed disaster is not far away as you so rightly point out.


Mike

Gentlemen, It all due to global warming.see my article in that esteemed periodical "The water users Weekly" A.Fudge

.

Tell me professor - are you one of the Double-Creme Fudges? I might have know your father.

Mike

No Sir, I am pure bred.It is not unusual for Sweetmeat references to be made. MY dear daughter Magnolia has been nicknamed "Toffee"!see my web site www.waterwater.co.uk to view my research.

Following on from Chris' good advice, whilst enjoying your cuppa, get someone to rev the motor up and down a bit. If you have a gasket problem you should see large air bubbles appear at the water's top. Incidentally, I found that thermo-syphon will still work on an Austin 7 provided you have the water level about 4" above the top of the cylinder head. Good Luck. Bill in Oz