Originally Posted By: SHOZ
Yes with liquids. Hydraulic or oil fittings. The teflon shavings, which are usually stringy, will clog the small orifices in valves or in your engine the small oil passages.
I have used tape on plenty of such fittings - brake lines, transmission cooler lines, and power steering pipes. I don't let the end of the tape get all the way to the end up the threads. Obviously, I cannot state with conviction that I have never had bits of tape get into the systems, since I can't get inside the lines. But, I can state unequivocally that I have never experienced any sort of issue related to clogs from bits of teflon thread tape.