Contour Enthusiasts Group Archives Forums General Troubleshooting What motor oil for Duratec?

From what I've heard from the pro mechanics (because I always ask...)

If you started with non-synthetic, stay with it. And for non-synthetic, it's not recommended to go above 5W-30.

If you started with synthetic, then you can, if you live in high-heat areas, go to a 10W-30. But still not really recommended. And/or if your engine has severe internal wear on it and you're getting oil "blow by" in the cylinders, you can up the weight a little to make up for the lower tolerances of the moving internals.

I started with, and have always used, Mobil 1 fully synthetic, 5W-30. I use a K&N oil filter. I get about 4500 miles on an oil change with that combo.

The Mobil 1 oil filter actually works a bit better than the K&N, but the 1" bolthead on the K&N makes filter removal a breeze on the 95 Duratec.

I've got 118K miles now and I've never had any oil-related problems.

One word: Amsoil (5W30)

Been using Mobil 1 - 5W-30 Tri-Synthetic for the last 10,000 miles.
No leaks and the engine runs smoother.
Starting with the next Oil Change,
I am going to use a K&N HP-2010 Oil Filter too.

Mind you, I've got 79,000 miles on the Duratec now.

There's no reason for not being able to switch to synthetic. The myth about synthetic causing leak is totally false. If it leaks after switching to synthetic, it's because the seals/gaskets are already worn. The sludge was probably keeping the oil from leaking out, and that's not something you would want to have. If it leaks, fix it the right way with the right tools and parts, not with engine sludge and comtaminants.

Any name brand synthetic is OK, 5W-30 or 0W-30. You may want to stick with the same brand, as gasket and seal swell characteristics may be slightly different, brand to brand.
I used Havoline synthetic exclusively for about 75K miles worth of driving, then switched to Mobil 1. Seems to leak oil now.