Abstract: Disclosed herein is an improved process for preparing an addition product of the reaction of a polyhydric compound and dicyclopentadiene, using a molar ratio of polyhydric compound to dicyclopentadiene of from about 1:4 to about 2:1, in the presence of an acid catalyst wherein the product comprises a hydroxyhydrocarbyl dihydrodicyclopentadiene represented by the formula ##STR1## and wherein R is a divalent radical of 2 to 20 carbon atoms selected from the group consisting of saturated radicals, aromatic radicals and combinations thereof, the improvement comprising employing as the acid catalyst a crosslinked cation exchange resin having acid functionality.