I did a headgasket job on my 940 turbo early in May, since there was a LOT of oil in the coolant, accumulated over probably a year or more. It's been running much better ever since, except I'm still noticing oil in the coolant tank at the high water mark. At first I assumed this was just some of the leftover oil from the leak working its way out, since I didn't do much flushing. But it recently seems to be accumulating again, and there is a slight slick on the surface of the antifreeze. Nothing like before, but still troublesome. The radiator is only a couple of years old, and the transmission fluid seems healthy, so I doubt it's the transmission oil cooler. I've done headgaskets before, and always by the book, this one included - never any problems. So unless the gasket I just put in was defective (Reinz), I'm wondering if the turbo oil cooler might be the culprit. I've never seen any posts about one leaking, but I figured I'd ask to see if anyone has had a similar experience.