Here's a sneaky trick to help getting the tube through the water jacket. Run a thin, stiff wire like an acetylene welding rod through the old tube before you remove it, then use the wire to help fish the new tube through the block.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!