Ive got a 87' chaparral with a mercruiser 4.3l two barrel engine in it. I bought a thermostat kit part# 18-3668 to install. It is the new design cooling system according to pics ive seen. The thermostat that came out of the housing fits in the sleeve perfect. The new thermostat does not. The question im asking is if you must take the sleeve out to install the new thermostat? All the gaskets and orings are the same, just the thermostat is different. Any help would be appreciated!!!
