Advice on oil..

[Butch]

Live in Michigan and winter getting close. Have a tick from 0-30 then disappears, 2004 Expy EB calls for 5w-20 has 214,000 miles on it. Would like to try switching to a synthetic oil just to run cleaner reduce the sludge etc. People suggest 5w-30 for upcoming winter and tick reduction, I worry about seals and so forth. Heard good things of Mobil 1 and filters. Guess looking for anyone that made the switch and outcome.

Thanks, Butch