Does it hurt if you over fill a 3.5 ltr engine by a half of quart of oil?

It has been my experience with my 91 v8 305 camaro that over-filling with engine oil can blow the main gasket between the engine and the transmition due to the oil pressure build up. It is always recommend to drain surplus oil overfill rather than leave it in. [if it's fresh oil, drain back into a container, pour into original oil container and keep it for top ups???]

This might not be the result for your engine, but if you start to find oil on the ground after you park, it's already happened! It's expensive to replace the gasket on mine as transmistion has to be removed or engine lifted to acess gasket replacement.

[Note: I discovered after limping it along with frequent top-ups after it started leaking purfusely, that my normal use of 100% synthetic oil, left in over the winter storage period, seems to have soaked the leaky main seal and I don't see much oil spillage on the ground now. I may be lucky and not need to change main gasket after all, but I know I won't allow any overfill in the future.]

edutainer