As they say, "It ain't the Dexcool's fault".
Dexcool DOES NOT go into systems which are exposed to the atmosphere.
The reservoir's cap is merely a flap. It only keeps bugs out.....BIG bugs.
Here's my sister's '99 XJ with ~150K on it's odo. Jug dino OC specials of varying brands using 5K OCI's.
New VC gasket kit from Fel-Pro included 19 hard plastic things which served as sealers for the bolts. I was surprised they worked.
The rubber grommets were shrunken, embrittled and leaking so I broke the elbow (front) and PCV orifice (rear) to R&R them.
I also bought the PCV to intake manifold hard line for $8 as I thought I'd use that much in solvents to clean the old one.
New cap, rotor, wires and plugs. New hoses too.
When the parents of the college bound girl opened the hood at 171K they both gasped, "How clean the engine is!".
Also, clean your diffy-ques.
Unscrew the trannie drain and 1 gallon of Dex/Merc exits. She had the NP242 and it takes the same juice.
What are those bridges shared by each cylinder's intake and exhaust rocker arms?