What is this oil anaylsis test you guys are having done and where do you go to have it done? I just replied to another topic about GM 3.8 engines about this? I have two of these 3.8s and the other topic talks about how the fellow uses 15-40- with 10-30. My Dad bought the 87 Riv I own and he orderd a Moly oil product out of a magazine. Supposedly, this Moly oil was one of the few additives really worth adding to oil? Was he correct? Man this site has got me wondering about a lot of stuff? My 87 Riv 3.8 was losing coolant this spring but the problem has disappeared this summer? About a half quart a month was going somewhere. Any ideas? 125,000 on this Riviera 3.8. Seems to be running good. I am getting 29 MPG at 55 miles an hour on the freeway. (YES, I stay in the right hand lane as you pass me by at 80!) Want better MPG with $3 a gallon gas? Slow down! Educate me please?