Ugh, I hate bi-est mechanics who tell people garbage. Synthetic is FINE. Your bearings arent made of LEAD. They are a high quality material that will almost never break down unless you run out of oil or your engine is beat on like a race car, or you never change the oil.
People say this because they think their so smart about bearing life.
The ONLY different between synthetic OIL and Mineroil oil is:
1. Synthetic tends to flow a lot better than mineral oil when cold, 90% of engine wear occures at start up.
2. Viscosity changes occure when oil is heated up, mineral oil holds its viscosity fine during normal conditions. However, during extream heat, or cold, synthetic oil maintains its viscosity way better than mineral oil.
3. Synthetic oil does not break down the same as mineral oil
4. People would rather stick with the old adage "every 3,000 miles". Well, I'd rather run a better performing oil and change mine every 6,000 miles.
5. Synthetic oil has more cleaning agents. But mineral oil has them too.
Some mechanics think if an engine has always seen mineral oil, that the bearing clearences will be too wide for synthetic. This is not true, as I said before. Synthetic oil holds its viscosity BETTER during extream heat or cold than mineral oil.
Some mechanics think sytnthetic causes oil leaks, NOT TRUE. Its simply exposes problems that ALREADY exists.
If your leaking oil at 146k. Its probably because you just need to do some routine maintanance. Fix your leaks, and I would continue just to change your oil in regular intervals, whether you use synthetic or mineral oil.
