sn95.4V

Hi,I swapped 5.4 DOHC in my 99 stang gt. I am wondering what thermostat temperature I can run in very hot area. The temperature in my country could reach 130F and more in some days. In this weather condition, Do you recommend running 170 t-stat or less? or its too lower and 180 t-stat is just fine? I know that running low t-stat could be bad because it will not close and the coolant fluid will run all time and it will not cool down in the radiator. What is your advice guys? By the way it is stock engine with Boss 302 intake manifold and x-pipe for now. It will be my daily driver car. Thank you

Buck Sergeant

sn95.4V, if your,entire, cooling system is up to par, the OEM thermostat should do its job.

sn95.4V

Buck Sergeant, So you do not recommend using 180 T-stat? I am currently not connecting the coolant system to the heater core. Any problem if I use 180T-stat?

Buck Sergeant

sn95.4V, I would use the OEM thermostat and see what the results are. Remember, water transfers heat more effectively than antifreeze so we recommend using the lowest concentration of antifreeze possible for your climate along with a product like Redline Water Wetter. Just make sure you have enough antifreeze in your coolant to keep it from freezing in the winter and always run no less than 20% in a street car. We do not recommend adding Water Wetter to coolant that is more than 40% antifreeze. Also the 170 thermostat is helpful if you have, or are going to modify the 5.4L. I think the 180 might end up being a all around good choice.