A very popular item in the UtterPower parts bin is our custom Thermostat Housing sold to hundreds of DIYers for Lister and Chinese horizontals.
Note: The world is not a static place, this thermostat fits the upper coolant port in most all of the CS engines I’ve seen to date, however; your engine may be different. If you bought a variant, especially a twin, there might be something new or different about the coolant flange. This one works in all the singles I’ve ever seen thus far, and if you engine uses the stock cooling flange and it is an unobstructed location—not in a tight spot between two cylinders for instance—this one should work.
All water cooled engines benefit from having the coolant held at the proper temp. A thermostat helps bring an engine up to temp quickly; this greatly reduces wear, and increases efficiency. Running an engine too cold is a waste of fuel and promotes wear.
Related Article: Thermostats in Thermo Siphon Systems
Above: Here’s the UtterPower Thermostat Housing. It is made up by tapping this massively heavy flange base and fitting the standard one inch hose nipple. The assembly is then machined to receive a standard NAPA part number 253 thermostat. The heavy flange fits standard Listers, and is used on the Chinese horizontal engines for radiator/tank thermo siphon cooling systems.
Please note: Newer thermostat housings are not this pretty, they are bigger and better in my opinion. You’ll have to add pretty to your own.