[MI2600]

This isn't exactly a rod question, but my wife's Mercury Sable manual says to use 5W-20 synthetic engine oil. This is the 3.0L Duratec engine. Since we have five cars between us, I'd prefer not to have to stock another type oil.
Can I safely change to a 5W-30 regular oil without damaging something?

[Dozier768]

IMO,Going from a synthetic to a non synthetic will not damage the engine, but will require oil changes more often, as far as the weight of the oil the difference between a 5-20 and a 5-30 isn't extreme and i couldn't imagine it would harm it. i would be mostly worried about damaging any power train warranty by not following suggested factory maintenance guidelines.

[adtkart]

MI.... You might want to read that manual real good. I worked at a Ford Dealership for a short time. We had a customer come in with the same question about synthetic oil. It turned out that it was just one of the "approved" oils for that veh. It did show a bottle of synthetic in the picture. I personally have never used the stuff. I have heard that you shouldn't change back and forth between the two. Maybe someone on here can say for sure with some technical knowledge as to why.

[MI2600]

Thanks. I'm hoping someone here can help.