Higher temp - reason is diesel uses the heat to ignite the next round of fire, if the motor is running cooler then you don't get as much bang for your buck type of thing.
The two temps are 160° and 192°. Now there are two types of thermostats on the market. the typical automotive looking one = means you can see the spring on the back side of the tstat and the type where it's all basketed = means you can NOT see the spring on the back side. You need to use the one that is basketed - reason is because the basketed one blocks off a portion of the bypass that is built into the block so that you get a more even running temp - with the std style you can run into low heat or over heating because if your blocking off the bypass the water runs past the block so fast that it's not there long enough to absorb the heat. Been there done that... Most of the guys will tell you to get your tstat at International or Ford dealers because they only sell the correct type but Napa and the like are now stocking the correct type I don't have the number handy but I know that Jim Williams (lucky_larue60) was the one to find the correct style at the aftermarket supply houses. So if you can't seem to locate it just drop ol Jim a pm or he might happen across this post and be a nice guy to just post the information.
