Excuse the complete noob question, but I've been pouring over these forums all week and my head's about to explode, so I just thought I'd get it out there and ask. Last year I got 1993 Honda Civic Del Sol Si. Engine is the D16Z6, 1.6L 125HP SOHC VTEC. It has been extremely well maintained given that it belonged to a guy who never crawled under it. It has a fairly complete service history. Everything has been kept up with, and oil has been changed pretty consistantly every 3K - 5K using QS, Pennzoil, or Valvoline 5w-30. I got the car December 2002 with 128,137 miles on it. Oil changes have been: 128,137m - Mobil Drive Clean 5w-30 + OEM Honda Filtech filter. 131,500m - Mobil 1 5w-30 + OEM filter 138,000m - Mobil 1 5w-30 + OEM filter The car currently has 141,400 miles on it. I drive it pretty hard -- about once a week I get it up in the 98 - 103 MPH range and heat the brakes up till they're pretty soft, but most of the time it's just your average commute with stop-go driving and 80 MPH on the highway. I'm very happy with the Mobil 1 5w-30 every 6000 miles, and it has consumed absolutely no oil since my last change 3500 miles ago. Should I put a more aggressive cleaning oil in it for awhile? I noticed many have recommended Rotella T and Delvac 1 for their detergent packages, and many people suggest the Auto-RX additive. I don't really know how I feel about Auto-RX. Every person I've talked to who knows anything has always said all oil additives are for idiots. Should I take the valve cover off and try to determine how dirty the engine is? There is some faint ticking for the first few miles after startup, but I don't know if using 0w-40 for the winter is the answer. Also, my GF has a 2001 Saturn SC2 with 42,000 miles on it. It has had the oil changed at the dealer every 3000 miles, and I just put Mobil 1 5w-30 in last week. I know the car's been maintained perfectly, so I doubt there's much need for heavy cleaning, but I did put the big orange Fram filter on it (I couldn't find the AC Delco part number and was in a hurry). Looking around the net, I have been given the impression that the Fram filter will cause her car will explode any second. I was going to start using Pure 1 or Motorcraft filters on both cars. People have said they may restrict flow, but with a synthetic 5w-30 is this going to be a problem? Thanks for any help.