Don't completely discount the turbo seals.

I've been wrestling with an oil consumption issue on the SDL. It's running about 1 quart every 1500 miles. Very little blowby. Oil smell in the vehicle, in the trunk, and in the exhaust. I believe that it's leaking into the exhaust and burning off in there.

If the oil was burned in the combustion chamber, in my case, 1500 miles equates to over 215 quarts of fuel. To this we add 1 quart of oil. So, the ratio is 1: 215. I don't think you could smell this in the exhaust, and, you certainly would not smell it in the vehicle.

But, the interesting point, and the reason for the post, is the fact that the situation gets far more pronounced after an oil change. I can't explain it, but there must be some additional oil pressure that forces more oil to the turbo and more leakage occurs, and more oil smell is present. So, if the valve guides caused an increase in oil pressure to the turbo, a slight leakage might be increased significantly.

I'm just tossing this out there, because valve guides and valve seals make no sense, unless one of them fell out. You have so much oil going through the engine that it has to be an obvious mistake if the head is involved.