A little while back I purchased an Accel tune-up kit from Summitt and also purchased a Hypertech 160deg. thermostat. I was thinking that since 160 is cooler than 180 so i purchased it. It was also a few bucks cheaper. Afterwards I noticed everyone here uses 180. since I have yet to install it, do I need to switch? Also, should I wait till I get a programmer?

 

I think a 160 will be too cool. I got a 180 thermostat and noticed a slight difference in performance. I'd go with a 180.

 

160 is too cold. Your trucks pcm will keep dumping fuel in the motor and try and warm it up and after awhile you will get a check cel and your gas mileage will probubly go way down.

 

Thanks. I will try to return it, or something.
Will your programer work on a 98 5.9L?

 

160 is too cold like the other guy said. Hypertech thermostats are of questionable quality also. A couple guys on here have had problems with them. Go to NAPA and get their premium 180 degree stat. It is like $7. You can put in the stat before you get the programmer if you want.

 

180 deg is the best way to go and Napa is the best source.