A system for cooling lubricant in a turbomachine includes a lubricant circuit for circulating a turbomachine lubricant, an air/oil cooler disposed in thermal communication with the lubricant circuit and configured to cool a turbomachine lubricant in the lubricant circuit by passing air over the air/oil cooler, and a compressor air circuit in fluid communication with the air/oil cooler and configured to supply air from a compressor of the turbomachine to the air/oil cooler. The compressor air circuit can include an expansion section to expand and cool air before effusing air to the air/oil cooler.