[Ian]

Originally Posted by johnjzjz

If you can pressure test the radiator with a pump type tool, pump it up to 17 / 18 lbs with car motor warm and spark plugs out, let it sit 10 min, check pressure and if down ! re pump it up, do this twice if it goes down fast 3 times if it goes down very slow, ( pressure that is ) from pumping up the radiator, after 1/2 hour of doing this and letting it sit now crank over motor with starter if raw water ( anti freeze ) comes out of any of the spark plug holes, you will than know what cylinder is the problem, and raw water not always, but could be a crack in the head or a cylinder sleave, if you do the job yourself make note, the gasket is the key in knowing, try your best not to wreck it, reading it is the way to know for sure, and if its bad have the head decked if it is a gasket problem ( is the cause ) jz owner Z Bros Racing 68 super gas nova 78 f body super street NHRA Divisional racing

VERY good advice. and I'll second trying to keep the gasket intact so you can try and figure out if its the gasket or the head/block.