Been a backseat reader here until after this last weekend. I know that the old oil question has been beat to death but I need your input. My brother bought himself a 2003 Skidoo Renegade 600HO with 1800 miles this past summer. Previous owner used a off brand sinthetic oil. My brother topped the tank off with Skidoo oil before we left for the weekend on a trip. We put on 150 miles when his temp light came on. he ended up loosing a piston and cylendar and towed it back 50 miles to trailor. After all was said and done it costed $1550 to fix. [V] The dealer said it was partly due to the oil. That you should ONLY use your manufacturers brand of oil. As the good ole saying goes...all the major snowmobile manufacturers do major testing on their brand of oils, so they know how the sleds will perform on the oil. Now my wife and I have 2 Arctic Cat ZRs. A 01 ZR600efi and a 02 ZR500 Cross Country. All my wifes sled (02) has ever had run in it is Klotz. She has put on 1600 miles with no problems but when her brother told the dealer about her using Klotz, he said she should change back to Arctic Cat. [?] We've stayed with Klotz as thats all the sled has ever had but is it a good idea to change to Arctic Cat or not? Her sleds power valves needed to be cleaned at 900 miles. Is this also due to the oil or is this normal and would Arctic Cat oil help the power valves? [?] Input would be greatly appreciated.