Mercury - Analog Block Water Pressure Sender DTS Engine Add-On 8M0145165. Overview. Digital engines offer a lot of information, but sometimes an old-school analog gauge is still the quickest way to keep an eye on cooling performance. The Mercury 8M0145165 Analog Block Water Pressure Sender gives DTS engines that option. It adds the analog water-pressure signal that mechanical engines already have, making it easy to run a traditional gauge at the helm without changing anything about how the engin