Gino's Garage Parts
 

I need a new thermostat on my 07 5.9 and have been told multiple times DO NOT USE AFTER MARKET THERMOSTAT! Well Geno's has a Gates t-stat for $16+ but it's not an OEM Cummins part. Has anyone used this t-stat and is it equal to OEM?

I wouldn't use an aftermarket t stat. In the first gen series 5.9, The Cummins t stat is redesigned with two poppet valves in it because of cavitation and air bound issues. Check with Cummins regarding the 3rd gen having the same issue,or not.

It lasts years longer than the chino market ones.

Edit: they're called jiggle pins, not poppet valves.

Stick with the Cummins one.

This is a well discussed topic... Some say the only thermostat worth having is the OEM one. Some say that they're not worth the high price for OEM and the cheaper parts store versions work fine. That said, I have a NAPA thermostat. Its been in there so long that I cant remember what brand it was either. But I do know that it works perfect and has the jiggle pins...and thats the part you want to be sure of. The Cummins engine needs those jiggle pins.
Other than that, Geno's Garage is a great company and they stand behind their products. If I had to replace my thermostat again I would not have a problem trying their much less expensive thermostat, or simply getting one from NAPA again. Its up to you...