Zetec - SAE 5W/30, 5W/40, 10W/30 or 10W/40. (Haynes)
Duratec - SAE 5W/30, 5W/40, or 10W/40. (Haynes)
Synthetic oils holds their high temp grade longer so that's good, the first number is the low temp viscosity whether mineral or sythetic.
All these oils, especially when hot, will flush the grease out of the hub bushes very nicely, especially the top one - if you do it with engine oil ripe for a change then you will also add corrosive by-products to the grease. Once you have done that crawl under the front of the car and pump clean grease back in to push out the oil, it only takes two minutes [or just use grease) ;-) PJB.
