First of all, I have been a long time lurker for some years now and finally join this site, but let me cut to the chase: Are older F22B prone to leak coolant and oil? It's hard to tell on the back side of the engine...leaking head gasket?

 

Depends on how well the engine was maintained/driven. There really aren't any glaring oil/coolant leak issues with the 5th gens unless you have neglected regular maintenance. Now you have to remember you are most likely talking about a 17 year old engine. It is bound to have some leaks by now.

If it is coming from the back it could be, the oil pressure sending unit, the oil filter, head gasket or the valve cover. How far down the block is it that you start to see the oil? If you can't tell. Then you will need to clean up the dirt & oil and run it for a day or two and check to see if you can follow where it is coming from.

 

Gotcha. Doing a favour for my brother in law as he is consider about leaks on their family car. The valve cover looks dry for the most part, but definitely wet between the head gasket area and oil pressure unit.