Hello everyone, My wife's minivan with 4 cyl. is used for driving to work 75%, around town 15%, and trips 10%. Work is only ONE mile away. Currently use 5w30 dino, 3,000 OCI. With 120,000 miles on it, there is varnish and crude visible under the oil cap. Auto RX is probably recommended. With this or future cars, is there a type of oil that might work best for short trip driving? Would synthetics be better for these conditions? It seems bad to extend the OCI with so much condensation occuring. Any ideas? We live in Michigan, with large temp. extremes. Thank you.