I own a 2007 bmw 750li and it has a oil leak i can't find. Is there a dye you can put in the oil to find the leak? I tried crawling under the car to find it, but oil is all over the engine now.
You can use dye which is made for oil like this from GM (will work with any vehicle).
Besides this, you'd also need glasses and a UV illumination source to find it, but you can find those readily as well.
Just put the UV dye into the oil, let it run, then search for the UV glimmer, and there you go.
There is no dye for the oil. Since it most likely already black shouldn't be too bad to identify.
What you need to do is clean the engine. Use a degrease then wash it but you will have to be extremely careful. BMW have a lot of sensors and any water intrusion will cause even more problems. If you have never washer an engine before before don't try pressure wash.
Then look to find the leak.
Many times the leaks is from the valve cover gasket.