Early model dipstick tubes used an O ring about 1/8" thick by about 3/4" diameter. Later, the shape of the tube was changed, and a rubber sleeve about 1 1/2" long was used as a seal. To switch from the O ring to the sleeve, you would need to change the dipstick and the tube to the later model items. The sleeve seal does a MUCH better job of preventing leaks!
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!