2003 Explorer 4.0 common oil leak problem areas?

[1996ex]

My 4.0 seems to have a decent oil leak and I'm wondering where the common trouble spots are. I read about PCV valves and valve cover gaskets and those sound easy enough, but I'm wondering if this engine is prone to leaking oil from more areas that are expensive to repair, like the main seal or oil pan gasket, etc.

Also, this vehicle has always used conventional oil -- at high mileage (163k) and with a leak, is it advisable to switch to full synthetic? I just want the chain guides and timing chain to stay healthy.

 

[TechGuru]

I've been using Castrol GTX 5W30 which is a synthetic blend since I got it. I'm at 240K without any timing service.

https://www.walmart.com/ip/Castrol-GTX-Ultraclean-5W-30-Synthetic-Blend-Motor-Oil-5-Quart/17200822

Also use the Motorcraft FL820S filter.

Full synthetic will make your leaks worse.