I'm so new here (one month) that I'm not sure I'm entitled to do so, but let me extend a
My wife's car from 1990-2001 was a '90 model Mercury Sable wagon, with 3.0L V-6, a near-twin of your car. Once past break-in, it lived its whole life with us on a diet of Mobil-1, 10w-30 usually, and ran beautifully on it. Even at the end, it consumed no oil and ran like new (was in the 110k range when it went. Thus, at least
generically this engine (likely what you have, though some Tauri of that era got the optional 3.8L) does fine on synthetic.
On the other hand, with your car now twelve years old, there is now a strong stability argument. Your engine is "used to" what it has been fed, and you might possibly cause a problem is you change to synthetic. One known mechanism is for newly introduced syn to wash away the possibly-present, thin coating of sludge or varnish which may have been keeping oil away from gaskets and seals. These need the oil to keep them from drying out and shrinking. Abruptly exposed to oil for the first time in a long time, such seals may, and I empahsize may, leak. But I also know people who've made such a switch with no problems. Let's hear what the others have to say.
