How likely is head gasket bad?

[megalotz]

Purchased a '02 Pathfinder LE. The previous owner stated head gasket was blown and was causing a massive oil leak. Otherwise, this thing is in pretty good shape. Now when I looked, I could for sure see a leak out of the valve cover. I mean this thing smokes like a mother. But I have noticed no overheating, doesn't seem to be power loss, no oil in coolant, didn't appear to be coolant in oil, but not sure because it's leaking so fast. Codes were for an O2 sensor for sure and cats I believe. I've already started tearing into this thing, but curious in your guy's opinions if this seems likely to you? It was confirmed to be a bad head gasket by a "mechanic", but that's just off previous owners word. This was a 2 owner/1 Family vehicle, all maintenance seems to have been performed regularly. Planning on doing a compression test, but how often does this issue come up on these? Thanks in advance.

side note, boy does thing 3.5 have alot more going on than my dad's 3.3 we had growing up lol.

[04pathse]

mileage?

[megalotz]

200k. Don't know how i forgot that

[abnrjd]

I recommend checking the valve cover gaskets. I had the same problem and when I changed them it was good 2 go. I would highly advise change all gaskets and take your time. A good source for parts is Rockauto.com.

[Buzzman]

Head gasket does not cause a massive oil leak, in general.
Blown head gasket usually means coolant in the combustion chamber (white exhaust), and coolant contaminating the oil.
I've been here for over ten years, and I've never seen a thread on head gasket failure.
I'd be very surprised if that's what it is.
If it's dripping oil, then I'd start with the valve cover gaskets.
If it's blowing blue smoke and using a lot of oil, then I'd be concerned.
Check compression for sure.
You may have inherited a Pathfinder that swallowed a few power valve screws.
If that's the case, you're pretty much screwed.