2006-2008 Polaris Snowmobiles FS/FST Service Manual., Page 58Get this manual
Maintenance Oil Cooler Configurations
Reference the following information to determine which oil cooler and restrictor type is installed in each model year snowmobile
CAUTION
Installing newer type oil cooler requires using that year's restrictor and sleeve combination
MODEL YEAR 2006 FSFST Oil Cooler PN1240256 (6 plate) Restrictor5135328 Service Bulletin added sleeve5135871 2007 FSFST Oil Cooler1240312 (6 plate wbypass) Restrictor5135328 Sleeve5135769 2008 FSFST Oil Cooler1240330 (4 plate) SleeveRestrictor5136216