A few months ago, I took my 1992 LeSabre to a shop regarding a power steering fluid leak. They discovered that the power steering cooler was the problem, and instead of replacing it, they offered to bypass the cooler as an alternative. They assured me that it would have no ill effects on my car. Sure enough, I haven't had trouble with it yet!

Can anyone comment on why the LeSabre needs the PS-cooler in the first place? Are there any circumstances (towing, etc.) when the car would require it?

Sorry, but your shop is FOS! The cooler was installed in an attempt of keeping the PS fluid cooler, therefore, extending the life of the PS pump and other PS components. Did you ever wonder why a car has a radiator or transmission cooler?