I know synthetic oil lasts longer than normal oil. If you run a car with normal oil for 50 thousand miles then put synthetic oil in, Will the synthetic oil leak past some of the gaskets?
2 . will synthetic oil thin a little more than normal oil when it gets hot running through an engine?
Synthetic oil will last forever if the debris is filtered out. Regular oil breaks down as the additives designed to fight contaminants that are a part of regular oil break down. Regular oil can be recycled by removing the contaminants and detergent residue, and adding new detergents.
Synthetic oil doesn't cause leaks, it just doesn't hide them. The reason some people say synthetic causes leaks is because there are no gasket swelling additives in synthetic oil. If you can't be bothered to change a bad gasket and want to run synthetic oil, you'll have to add your own gasket swelling juice.
Synthetic will work exactly like regular oil in an engine, with the exception of performing much better given extremely high temperatures. Again, no additives to break down and turn into sludge.
