2010 Ford Focus se 2.0 170,000 Noticed the car getting warmer with some driving around town investigated and saw low coolant, topped it off and watched over a few short drives. The car didn’t ever get as warm again, but the coolant would drop slightly after each drive. Inspected all the coolant lines and radiator several times and never found a leak. Used the UV dye and still never saw a leak on any extensors component. Just for kicks I opened the oil cap shined the light in and the compartment inside the valve cover has green specks. I checked the oil initially and saw no signs of coolant. (The chocolate milk color is seen before) but the UV reaction inside the valve cover tells undoubtedly the coolant is getting into the oil. During this process I also pressure tested the system and I lost pressure at a rate of about 1 psi every 5 min. No external leaks found during that test. Assuming it was a head gasket problem I used the blue to yellow liquid combustion test. After several tries I never got the liquid to change to yellow. So from what I understand there is no leak from the combustion chamber to the cooling system. But there is a leak from the oil to the cooling system. I just wanted to make sure I am thinking along the right track and see if anyone has suggestions on things to check next. I don’t mind replacing a head gasket if that’s what it is. I’d just like to rule out any other sources of the two mixing, like a crack in the block. I’d appreciate any and all feedback.