Cooler Oil 1- (Check fitting section to ensure you're getting the correct part)
Oil Thermostat replacement system for your 1998-2009 CM570, CM870, CM871 ISX  
Cummins that directs a continuous oil flow through your oil cooler to significantly reduce oil temperatures to within 5 to 10 degrees of your coolant temperatures. 
 Optimized cooling allows for reliability and longevity of crucial internal parts. Most importantly a piece of mind going down the highway knowing your oil isn't boiling!