72 Pinto Wagon, 2000 cc engine with 58000 miles.   When I began to restore this car the underside of the hood had a significant coating of "gunk" (grease like black crap, been there a long time.)  I removed hood, used a putty knife to scrape this grease like accumulation off.  Sanded hood underside to metal after major cleaning.  New coat of primer.  Noticed a new spatter of oil on the fresh primer.
My guess is it is coming off the cam timing pulley.  Sort of "cast off" the edge of the pulley.  I am guessing it is the front camshaft seal.  Two questions;  1) Is it a big deal to change out this seal?  2)  Looks like to me that it leaked for years with little effect.  Do I really need to change it?  jt

The advantage to changing the seal would be that you get a look at the timing belt and tensioner. If its still got the original parts in it, wouldn't be a bad idea to change them out to prevent any breakdowns. It would even be a good time to change the crank seal.