I have a 1997 jeep grand Cherokee 4.0L I6 and it sometimes has trouble starting in the winter. I'm thinking about switching to synthetic oil so that it flows through the engine better in hopes that it will help my problem. Even if it doesn't help that problem I know that synthetic oil is better for engine life then conventional oil. My main concern is that I'm not sure if it's safe to switch from convention oil to synthetic oil since the vehicle has been running on conventional oil for 20 years now. I would appreciate your thoughts on my issue, thank you.
My car has 181000 miles.
My car has an automatic transmission.
I would recommend using a simi-synthetic high mileage oil rather than straight synthetic. High mileage oils are designed to reduce friction and have extra additives embedded that assist in removing unwanted deposits. As far as the reason your engine struggles to start in the winter, I would first work through the three main starting problems. Battery, alternator, and starter. If you cannot perform this diagnosis yourself, I would enlist the assistance of a qualified mechanic.