I replaced the lines in our '99 Yukon with Delco originals as suggested by their popularity on Rock Auto. The lower line wasn't bad. But, the upper line was just as NOREVERSEYUKON says. Old line was so rusted that it easily folded in the middle for easy removal!! That rust is why I changed it.
For the new upper one, I saw real trouble coming before even starting the job. So, I cut it down at the section that runs along side the engine oil pan, about 6" back from the portion that rises to the radiator fitting. Made inverted flares--tough to make seal without good equipment, as was I. But, if you grease them thoroughly on the bench, then wring them tight on the coupling, hard, many times until they tighten firmly with only minor nut rotation, they'll be pretty close. If they leak slightly on the car, you'll have to continue the tightening and loosening some more--I did. Before you'd cut the line you want to be sure it's at a place you can reach if necessary with the double wrenches.
The two piece line is a breeze to put in. Well worth the extra steps.
