I agree with Dave- go with synthetics! I recently changed ALL the fluids in ALL of our cars to Amsoil synthetics. Everything runs better (smoother). I even gained 5 MPG in my 05 Ram, just by changing the oil! I've been running Amsoil products in my Daughters 93 Capri N/A for almost 4 years, and haven't changed the oil in that whole time! We have the oil analyzed ($30) and checked for contaminants, then change the filter, add a quart, and we're done!
My "Super-Roo" uses all synthetic - coolant, oil, and trans. This past Tuesday, I lost my alternator belt, and needed to drive almost 20 miles with the water pump not spinning. I had NO issues! I firmly believe the synthetic coolant kept the engine from overheating, while I raced back to my garage!
--Russ