- Nov 1, 2005
- 57
- 0
- 0
i just bought my 91 gt about a week ago and i want to change the oil before i put it on the road but i dont know wether to use synthetic or not and what type because i have no idea what has been used in it in the past or what is in it right now due to only having 4k miles put on it since 2001 by previous owners. Needless to say the last owner does not know if synthetic has been ran in it or not. The car has 82,000 miles on original motor. Synthetic or no? and what weight/brand? I heard if you change to synthetic from non-synthetic, it could worsen oil leaks. Is this true?

