I used Lucas Power steering leak stop in my old FERD van. It was howling pretty loudly and I needed to make a trip before I could change the pump. I pulled some of the old fluid out, put the Lucas in and after about 5 miles it quit howling. That was three years ago and I still have the same pump on the van.
I didn't count on it making the pump quieter, I just needed it to make a short trip. Best money on additive I ever spent.
