Really depends. Loose passive? Loose aggressive? What is their post flop play like? Just some general thoughts:
If they play fit or fold post flop, you can raise 100% of the time regardless of whether they are loose or tight preflop.
If they are loose and passive both preflop and postflop, I don't mind open limping many hands. You generally don't want to be bloating a pot OOP against someone that calls a lot.
Against people who are LAG preflop, you're going to have to tighten up a bit. If someone raises 100% of your open limps, a good adjustment would be to start open limp-reraising the top end of your range while open raising the middle of your opening range like normal. Once they start checking their option after you limp, you can start open limping again with the bottom end of your range.