Opinions on oil

[Z Factor]

Originally Posted by jrd1990zr1

I am not sure if the oil currently in the car is a synthetic. Is there a problem with any residual oil in the engine mixing with the Mobil 1?

Thanks guys for the advice.

There is a good chance the previous owner used a synthetic as most people who own low mileage ZR-1's do not skimp on maintenance. There will be some old oil in the system since you can not get it all to drain. However if you want to be sure there is no regular oil then drain it over night, replace with synthetic then change it again within a short period of time. As to the most common oil used, Mobil 1 is at the top. Here is a poll on the filters forum members are using.

http://zr1netregistry.com/forum/show...6&page=1&pp=40