I have a 2002 Focus 2.0 spi. It dropped a valve seat at 142,000 miles. Replaced head and pistons rings and rod bearings. I have been rebuilding engines as a sideline for 45 years. This one has me baffled it is using 1 qt every 500 miles but I don't find any leaks so I assume it is burning it yet I see no smoke and it runs beautifully. I used one of the NPR rebuild kits off Ebay and the parts looked real good. And a reman head from Cylinder heads International with valves. I am leaning towards replacing valve stem seals since I can do that without pulling the head. The question is has anyone had this issue using these engine parts or that brand head.