hoses with pin [ed - prod with a sharp implement] holes in etc. you will only see them when the cooling system is up to pressure and the engine is revving.
Pinholed hose can be even more devious than that.
Twice in my life, on different cars, a mystery leak has been down to a tiny split in a hose. Start from cold, no leak; warming up, no leak - the cold hose was stiff enough to keep itself sealed. Full temperature and pressure, no leak - pressure and combination of shaped curvey hose keeping the split sealed. Switch off and wait ten minutes .... dumps a half pint and then reseals with no trace except the puddle. But only sometimes. Lil sod to catch that!!
Suddenly ejecting coolant could be a pointer to the LPG as already suggested - in some failures, gas pressure can be applied to the cooling system. Clue - very hard hoses and header tank venting.
Bubbling in the header is indistinguishable from 'normal' gasket failure etc, the hot water seems to absorb the smell component of the gas.
Slight reluctance to crank on morning start-up can indicate leaking into a cylinder. Pull the corner plugs (1, 2, 7, 8) and look for rust or steam-cleanliness. Headgasket hopefully. Leaks into the other cyls are probably liner issues.
Does it smell of antifreeze under the bonnet? Seeping radiator. In the cabin? Heater O-rings. Misting windscreen? Heater matrix. You got to seek all the clues you can.
Be aware you might have a combination - for example an LPG failure pushes out water until its low enough to overheat, then severe overheating is followed a couple of weeks later by head gasket failure, just as night follows day. Often a V8 with water problems will need more than one fix because of knock-on effects.
cheers, Ross K
