The major difference between dino and synthetic is the ability of the synthetic to retain its viscosity longer. Synthetic also has better polymers and cleaners to stick to the moving parts.

AutoRx does not work with synthetic oil. So before you switch, run 1-3K miles with autorx to clean out the engine and then swap oils and filter.

When I went 20K miles/year with the 1998, I used to change the filter at 5K and flush the oil at around 10K. Synthetic is great!

Klaus

PS. Three hard parts to a 5 cyl Tbelt change. Finding the microscopic timing mark on the crank pulley. Getting the old belt off the crank. Getting enough tension between the cams when putting the new belt on.

Pull the spark plugs before trying to crank the engine by hand, this lets you feel any obstruction by valves. You need to turn the engine 720 degrees to get all the valves to lift.

If you have a broken front mount, the engine might be too close to the subframe to get the belt out. With a 2X4, lift the engine 1/2 inch. Some have reverted to cutting the old belt off which I do not agree with.

Use whiteout or white paint to mark the timing marks before the old belt comes off, MUCH easier that way. Read up on how the tensioner gets adjusted.
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Always willing to listen, just not able to take direction.