You should use the oil recommended in the owners manual. If you don't have one, get one from MOTORLIT.COM. No. The use, or not, of synthetic oil is completely up to you as the owner of the vehicle, and has no effect, good or bad, on your vehicle's warranty. Warranty terms cannot compel you to use specific brands or types of oil, only the viscosity(5W30, 10W30, etc.).
5W30 full synthetic.
I like to use Valvoline synthetic and have had good luck with it.
5w 30 synthetic oil
According to the 2000 Mercury Cougar owners manual ( 5W-30 ) for the four cylinder and V6 engines
Yes you can.
Engine oil?? 5W30 synthetic is best.
The correct oil weight is now 5W20; it used to be 5W30, but Ford has recently allowed your engine to use 5W20 as an energy saving oil. If you don't use synthetic oil, stick with the 5W30; non-synthetic 5W20 will burn out your engine faster than non-synthetic 5W30.
always use synthetic if possible
You need synthetic oil
synthetic !0w-40
5w30 full synthetic
the mixture is 50:1 I would use synthetic oil