36300 miles
just purchased used 2005 Q45 9/3/09 that has no manual and is low on oil. It is holiday weekend, as soon as I can I will take it to a inifinity dealer, but I was wanting to add some oil before tues
I am not sure wether the oil in the vehicle is synthetic or not. If I add a synthetic oil to the vehicle and it does not have synthetic oil will it hurt anything?

What ever your owner's manual recommend.

How many miles do you have on your Q? do you change the oil regularly?

We use regular 5w30 Mobil oil in all our oil changes, or if the customer prefers synthetic we use Mobil One full synthetic.

So for your Q, I would go with Mobil One 5w30.

I use Pennzoil in my Nissan (which owns Infiniti) & it has been great. But what exactly your car needs would be in the owners manual. There is a section dedicated to the oil & what type, how much etc... It does differ from car to car.

i use synthetic in everything. your Q ship probably uses 5w30

there's a sticker in your engine bay that tells you

I also use pennzoil and i am quite happy with it. All the best.