I've never done an engine flush before and was wondering what experience you've had with it. I recently read an article on a person who had been running synthetic oil in his engine since it was broken in and still had clogged oil passages, which led to some engine problems and subsequent teardown. Any feedback would be appreciated. My '97 had 31K on it when I bought it, and I'm pretty sure it never saw synthetic oil until I changed it out. I always thought synthetic oils were not prone to clogging small passages.