Solving the Avanti "Hammering" Mystery: A Guide to Heater Control Valve Replacement
Does your 1984 or 1985 Avanti sound like "somebody is building a house in the back seat" when you turn on the heater? You aren't losing your marbles—you're likely experiencing a factory engineering oversight. In this article, Dan Booth recounts how he discovered a reversed valve installation that caused a notorious hammering noise in new Avantis, leading him to modify over 100 factory units.
Discover the streamlined solution: NOS Part #1702187. This universal in-line cable-controlled valve replaces five previous styles and eliminates the need for bulky mounting brackets. Most importantly, it operates in the correct direction, unlike many aftermarket replacements that reverse your console lever settings. Learn the step-by-step method for a clean installation, including how to handle mixed hose sizes using the NOS #1701476 reducer.