I have 1989 Mustang GT with a re-manufactured engine from Ford. I have 6K miles since the engine has been rebuilt. I would like to change to a Synthetic oil - like Royal Purple 10w-40 weight. The question is will this cause me a lot problems. I don't see any leaks currently, but is there anything else with this change that could cause me real issues.

 

I have switched many engines from reg to synthetic, some developed leaks and others did not. Whether the seals will stand up to synthetic seems to have a bearing on the results.

 

Thank you I will take this into consideration. Have a Great Weekend!