I change my oil every 200hrs (roughly 10K miles) have been for for a while. I use synthetic oils. If you are concerned with the heat you can bump up the viscosity a bit to a 30 and it will be fine in high heat situations. I have ran a 10W30 in the Duratec with no issues. As far as oil types. Humm it is what you believe it is. I am currently running my Duratec with this. Just about ready to drain it and test the oil but no issues so far, but I will let the oil test speak to the results.