An external heat exchanger is used to transfer heat from a compressor lubricant to an expanded working fluid, thereby cooling the lubricant. The heat exchanger may also be used to sub-cool condensed working fluid with the same flow of expanded working fluid. A horizontal scroll-type compressor includes an intermediate lubricant sump between a main bearing support and a scroll member. A counterweight on the crankshaft can travel through the lubricant in the intermediate sump to splash the lubricant around. A horizontal scroll-type compressor can include multiple machined surfaces that are utilized to precisely center and align components of the compressor.