Yes, it's a fairly tight slip fit into the hole in the block- - - -no threads or other means of locking it in place. I use a little red Loctite on the tube when I re-insert it to make sure it stays put. One good way to grip the tube for removal is to tighten a heater hose clamp around it very firmly, and use the vise grips on the clamp jackscrew instead of gripping the tube directly with the pliers.
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!