We have been running
Butlers since '85 (I know, were old) Do you guys have any advice on using synthetic motor oil in the Savana vs regular oil?
Yes, GM recommends using synthetic oil, as do many other automakers.
We have ALWAYS changed oil and filter monthly. Would we see any benefit to switching to synthetic?
Yes, you won't be changing your oil so much. Skip the rest of the message if you've heard this from me before.
Regular oil contains impurities that will eat your engine if they aren't held in check by additives. Regular oil doesn't break down, the additives break down. which then exposes the engine to the impurities. Synthetic oil has no impurities.
Another thing that can happen to regular oil is sludge build-up. A lot of modern engines have parts like cylinder heads or turbos that run hotter than the rest of the engine. The heat/cool cycle causes regular oil to turn to pudding, which will absolutely kill your motor. Toyota had to do a lot of sludge flushes and engine replacements and offer 100,000 miles warranties due to sludge, and then required using synthetic oil.
Do not use any partially synthetic oil! The regular oil component makes it no better than other regular oils. Also be aware that one additive used in high mileage oil is a gasket softener that helps keep your dried out old pan gasket from leaking. Moving an old vehicle to a pure synthetic may expose bad gaskets and you'll see leaks.
We run Mobil 1 and change it once a year, even though changing the oil isn't needed as long as carbon is filtered. We use high quality filters and change them at normal mileage intervals. In 25+ years of using this program we've had no engine wear problems, and now use synthetic in anything that uses oil.
