Postby smj999smj » Mon Feb 25, 2019 1:25 pm
I really don't like head gasket additives, but I understand your point. Head gaskets are a real pain on this engine because the front cover and timing chains have to be removed. Plus, you have to be very careful not to mix up the bucket tappets because they are different sizes to adjust the valve clearance (at least they are on the 4.0L...the 3.5L may have bucket tappets with shims of different sizes, but same deal as far as not mixing them up). If the radiator is sludged up, it should be fine.
If you can see the top side of the head (you may need to use an endoscope) and there is no "custard" on it, just only in that oil cap extension, it may not be a head gasket. If the vehicle was used for lots of short trips, it might just be condensation mixed with the oil. I would clean it out real good and keep an eye on it. If the contamination is all over the top of the head or can be seen on the dipstick or in the oil when drained, that would tend to favor a bad head gasket, especially if you are still loosing coolant and there are no leaks.