Well, the question is just that. I'm not sure how to use dye, or where to find it. The car is a 1995 Mazda Protege, 1.5l DOHC engine. This car had no leaks! Then my wife took it out for some "unexpected" off-road duty.... ended up scraping the catalytic converter. I don't "see" any other damage. However, when she got back the car had developed a slow oil leak. I can't see any problems with the oil pan. Bolts are tight. The oil seems to be coming from higher than the level of the oil pan... The filter is tight. I don't think it's the front seal. Does an oil leak tend to get "blown upward" as you drive?