What's the best way? My leak is coming from the back of the engine, but I can't see where. It isn't a rear intake leak, as it's dry from where the head meets the block. It's very hard to tell where it's coming from. I keep thinking it could be the rear main, but I notice that it does build up on the pan and drips from the pan plug.

Any good techniques? Would adding dye to the engine oil hurt it?

 

go to an autoparts store, buy the dye and get a blacklight. It'll show up like none other. I used it not too long ago to find a leak.