I have a 1995 Subaru Legacy (2.2L boxer engine) with about 175,000 miles. The engine has run on full synthetic since new, but is now using about a quart every 1000miles. Last oil change an oil treatment additive was added to the 5w30 Mobil 1 synthetic, but it didn’t help. Since adding synthetic is e…

Adding conventional oil to synthetic

Caddyman July 15, 2010, 2:24pm 2

Any SAE rated motor oil can be mixed with any other with no problems. That’s one of the requirements to get a SAE rating…You might try a 10/40 oil during the summer months…A quart every 1000 miles is not that bad…