I have a 1992 300 TE wagon with 132K miles on it. I don't know what type of oil was used previously. Suprisingly this car has virtually not oil leaks or even seepage. I say suprisingly becasue I have another 1992 300 E sedan with 126K miles on it and it does have some oil seeping. I changed to synthetic oil Mobil 1 15W-50 in the sedan at 60K miles.

I'm just wondering if under the circumstance it would be best for me to just use dino in the wagon.

Below is some information I got from checking this topic.

From what I've read, the synthetic oil can remove deposits left by the natural oil. The concern is these deposits may be blocking leaks. So by switching, you end up leaking oil. Some people mistakenly blame the oil for causing the leaks.


Switching to synthetic on a high mileage car? You may or may not have problems with leaks. Gasket and seal material has gotten better lately and the detergent properties of good synthetics are not as harsh as they used to be. It all depends on how much the sludge in your engine is acting as a seal for the oil.

Not a viscosity issue WRT leaks. Synthetic oil has more detergent properties. It will remove the sludge that is plugging the leaks.