Well guys. I have been reading from this board for over a year now. I have tried many different oils. Synthetics, Royal P. Amsoil. Mobil 1. And most recently synthetic blends Schaffers supreme 7000. With an added bottle of Moly EP additive. I got a great oppurtunity to speak with a guy at the auto parts store that has worked on engines for over 30 years. Tearing them apart ect. What promted me with this whole oil thing is most recently I read on this site about Castrol Syntec Blend 10W30 is rated ACEA A1 and A5. Not to mention Exceeds ILSAC GF-3/GF2. and Jap engine wear test. I have never seen a dino oil with this ACEA A% rating. In fact onl some synthetics have this rating. I asked the guy what he thought about Castrol. "AN EXCELLENT OIL". He said you wont have to worry about this oil sludging like Quakerstate or Pennzoil. The two worst oils according to him. Here is the kicker. I was reaching for my usual mineral base engine flush before the oil change at $3.97. He Grabbed that and said. " NO NO NO.. use this. And gave me the Marval Mystry oil. He said this was the best stuff for cleaning the engine , has a lube and when put into oil, will keep that engine clean. ANd is safe. So Off I went. Put about 1/4 bottle in the tank. The rest in the oil. Drove home 32 miles. Dumped the oil/filter put on my ST filter and added my 4 1/2 qts of Castrol Syntec. I do admit that I did add that bottle of MOlY EP additive that I had from Shaffers. Hey, can't hurt to have more Moly/ Any way. I am DONE, THROUGH, AND I BELIEVE A TOTAL WASTE OF MONEY TO USE SYNTHETICS WHEN THESE NEW OILS PROTECT MY TRUCK, A LOT LONGER THEN I CARE TO OWN IT. FRANK MICHIGAN. I am going to 10W40 Castrol come warmer weather.