one of my buds told me that replacing my stock thermostat with one that works for 15 degrees cooler would be good for my motor and run a little cooler. what are the pros and cons of this and does anyone KNOW what would be the best thermostat temp to get for my truck

 

According to one of the local online tuners, he found out our truck engines run most efficiently at 192-198* (somewhere in that range). I dropped mine to a 180* thermostat when I put in my oversized radiator, and I liked having the engine run cooler. However, you risk running the chance that your ECU will recognize it and run open loop, dumping fuel into the engine to warm it up to operating temp. Either way, its your preference.

 

The best thermostat is a stock 192.

 

Your best bet would be to stick with the OEM thermostat and have a good tune written.

 

I was told to keep with the factory temp.