Ok im really succombing tothe terrors of catastrophic water loss...and have looked (for the nth time) at the faq suggstions and a few things bother me..

1. I have a 940 but my expansion tank isnt as described
2. I HATE the idea of drilling holes in (no doubt) expensive peices of volvo kit
3. I hate mechanical switches
4. I cant easily source a float switch rated above 100 degrees c..

so i was playing with a few ideas and came up with a nice idea..question is does it work (can it be made to work....)

if you removed the rubber hose from the bottom of the expansion tank and inserted a small length of said hose, them a piece of metal pipe (copper, ally whatever) and connected the hose to this and clipped everything tight and refilled you would then have a metal contact electrically isolated from the car by rubber except for the fluid in it connecting it to the block...i.e. it would be earther to the block by the fluid. If you lost fluid therefore you would loose the earth (or loose a substantial amount of earthing).

now the question is (need to gt busy with a meter etc...and this has just occured to me) do you have ENOUGH earth there to hold a small relay open give n12 volts applied to the other side of it....?

if the answer is yes...then you can wire the relay to fire a buzzer light whatever and this set up has several advantages:-

1. no hole in tank, no rubber washer to age etc.
2. its fail safe..i.e if it fails the light comes on
3. it may well be possible to make it solid state..i.e. no moving parts!
4. it shouldnt be effected by cornering/cold coolent levels etc..
5. it should be cheap.


anyone got any thoughts or no the resistance qualities of water/coolant mixture (before i take up my multi meter and go check?)