Home About DOHC V-8 SOHC V-8 DOHC V-6 Coyote 3V Mustang 05-06 3V Mustang 07-10 EcoBoost V-6 F-150 Expedition V-6 GT350 GT500 Cross Reference Thermostat Basics Coolant Filling Installation Motorcraft Coolant Purchase
About
The tried-and-true swap to a lower temperature thermostat is nothing new. If you've made upgrades to your engine, and are looking for better performance, a drop in temperature will always be a benefit - especially if you are a racer. I felt a 160° thermostat was a bit on the low side, but 170° is perfect, especially if you are replacing an original thermostat rated at 180°. It’s also feasible to simply use a 180° version in place of one that is rated higher, especially if you feel that 170° is even too low.   While there are some options out there to buy current "alternative temperature" thermostats, I made went to Stant right from the start (Stant, by the way, is the OEM supplier to Ford). Thus, these are all OEM-quality thermostats using actual 170° "heat motors", not just generic versions using lighter springs. They are also a perfect fit, so you’ll have no worries about improper coolant flow. Since there is no middle-man to go through, the savings are passed on to you! Even better, a portion of the proceeds go to St. Jude Children's Hospital. Here is a look at a 170° thermostat in action, compared to a factory Mustang 180° version. Mine (on the left side in each) begins opening just as it passes 170°, and is fully open by 190° - while the factory thermostat is catching up. If you want to drop your engine temperatures 10-20°+, you aren't going to go wrong here! Once you install a new thermostat, there are two considerations that come in to play in order to take advantage of it. First, a proper coolant mixture is important. See the Motorcraft Coolant chart for mixtures based on your climate, which is also available any time through the tab at the left. Additionally, your fan settings need to be changed through a tune or with a hand-held tuner. Otherwise, you will only benefit when the vehicle is moving and air is flowing through the radiator. This is a good starting point, using an SCT tuner and my own 2003 Cobra as an example (the Cobra has unusually high factory fan settings already). The low-speed fan turns on at 186° now, and the high-speed at 190° if necessary. The low-speed fan here will shut off around 176°, with the temperature drop shown on the Aeroforce Interceptor mounted on my steering column. All have been used in a wide range of vehicles, and they absolutely work! As always, performance modifications to your vehicle are undertaken at your own risk! Although a thermostat swap is straight-forward and non-complicated, you are ultimately responsible for the work as well as the outcome. Please use factory service manuals and follow their procedures accordingly.
About