The "S-10" days were 1984-1991. I THINK the oil weights were both 10W-40, maybe both were 5W-40 or 5W-30. The 3.0L Stratus R/T got a change of M1 (0W-40???)"15,000 mi between changes" oil when it became available during the spring/summer of 2005 in prep for a trip to Fl.After the second fill-up I was not happy with the mileage I was getting, seemed to be down 'somewhat'. I went to a tire store to get my wheels re-balanced and had them change the M1 out for (their offering)Valvoline semi-syn 5W-30. 5K mi later in went the Amsoil 0W-30. I had been using M1 5W-30. Since I have been doing recommended-interval changes up to this point with the M1 on a engine in good condition I don't have a long enough time line to compare the Amsoil and new formulation M1 for "bur-off" like I did with my S-10.
quote:Originally posted by Motorbike:quote:Originally posted by airnut:
Personal experience: Mobil1 'burns off' faster than Amsoil ('83 2.7l Chev S-10 ). I don't have any extended experience with Castrol Syntec. During the days of 10,000mi powwertrain warranties I changed to Amsoil in my S-10 at 10k mi, engine, trans(auto), xfer case and both diffs. I changed oil and filter at 20k mi and filter with top-off at 10,000mi. At the 10k interval I may have used 1/3 qt of Amsoil. At the same interval with Mobil1 I would be close to 'add', and much darker than with the Amsoil. At 165k mi I had compression of 158 to 162psi across cylinders with the four cylinders in the middle being within 1lb., no drips, no smoke, 28mpg highway. I recently put Amsoil 0W-30 in my 50k mi 3.0L(mitsu) Dodge Stratus R/T. In the course of the last two weeks my engine seems quiter at idle, I seem to be getting consistently better mileage (+1.25 - +1.75mpg)over Mobil1 (finally ordered Amsoil on-line), and the occasional, almost imperceptable 'twitch' in my tach at idle has gone away I was actually considering plugs, etc. even though it came with platinums for 100k mi(you have to remove part of the intake to reach the back 3 plugs...). I haven't used any of the other 'boutique' synthetics, and given my experience with Amsoil and the long drain intervals I will be using, I'm not inclined to do any switching now.
In 2001 , Mobil totally reformulated their PCMO synthetics . To get a better idea of what you are saying please post the year of the Mobil 1 that you used . Was it 1993 ?
Actually one quart lost in 10k miles is not bad at all for a motor of that design especially when compared to an oil which is prone to oxidative thickening upwards of three centistrokes in the amount of miles .
50wts do tend to seal the rings better than 30wts ... so the experts write on the internet anyway .