Installation Time: Less than 1 Hour
January 12, 2017
Perfect fit for EcoBoost
I installed this in my 2014 Taurus SHO. I know this thermostat is mainly for the 4.6L DOHC and 05-06 Mustang GT, but the Reische 4D is also recommended for the transverse 3.5L EcoBoost V6 (SHO, MKS, MKT, Explorer, Flex) engines replacing the stock factory 180F unit. The Reische is different from the Evenflo sold by Livernois (aside from being 170F versus 160F) because it is a modified cold-side thermostat (same as the factory EcoBoost thermostat) and has that unique bypass unit on the bottom. The Evenflo is a modified hot-side thermostat that works in the Mustangs, but you don't want to use that for the EcoBoost motor as it is designed for a cold-side thermostat.
I noticed an immediate difference in cooling even without tuning the fan turn on point. While cruising off throttle, the ECT will drop quite a bit (into the 170s). While on throttle in cruising conditions, the ECT will try to stay around the 180s. Cold starts and warmups are not affected, nor is my heater output in single digit winters affected. I currently have my fan turning on at the stock setting, but will adjust it once I get more datalogging done. I will most likely just set it to turn on around 190F to prevent the fan from running all the time even in the winter but as far as I can tell, a tune isn't required as there's nothing that important to tune for the thermostat other than fan turn on points and when to switch base fuel tables - which will work fine as-is.
I extracted about a gallon of coolant from the degas bottle before removing the housing to swap thermostats. The gasket is included with the Reische and it is just a standard Motorcraft RG-571 from the looks of it.