i have just done a top end rebuild on my 2wd sapph including arp stud and nut kit and a group a headgasket.its using around a tank of water every time i take it out.no more than a tank.when i blow through the relief valve on the cap i can blow through it no problems with no resctriction,surely this valve only vents a little under high pressure.i think the water is escaping through the cap by evaporating.anybody else experienced this?

 

bloody hell thats some leak!how many miles does it do to lose a tank ?does it do it no matter how you drive it?any excess white smoke?although hard to tell in the cold weather

 

check around the thermostat housing going into the block cause i think it would take a while for all that water to escape through the cap hole vent. plus, and this sounds a bit stupid but when you stop and check to find the tank empty blar blar blar, is the temp gauge going up badly.

 

it probably only done about 150 miles,no sign of any leaks or overpressureisation of the hoses.it doesnt get driven hard.i have noticed the cap hissing quietly after i park it up though.should i be able to blow through the hole in the cap?it doesnt run very hot at all,only goes up to the bottom of the r on the norm on the gauge!

 

well the temp is fine then. i dont think you should be able to breath down that pipe, though. if you hear hissing on the cap change that then go from there. and check the pipes too. they should be slightly squishy when the engine is cold and near enough had when the engine is up to temprature.

 

Had this on mine after a complete engine build,it turned out to be a split heater matrix,water was running under the dash and under the carpet.Shit myself but onlycost £30 to repair and a days messing!

 

I have just done a head gasket on mine for similar reason and then discovered a leak at the water pump, which cured all problems once I did it

 

i renewed all the pipes with samcos,all the gaskets and pump at the same time,there is no sign of water anywhere so i suspect the cap,ill check the carpet though.i topped it up days ago and it hasnt lost a drop.it has not been started though as the fuel pipes are off as im having new end crimped on.

 

Lee get the system pressure tested,if your stuck,gives a shout and will pop up and have a look

cheeRS stu

 

do you have a pressure tester?i have them microfiches here for you aswell!