Blue smoke on cold starts.

I went ahead and pulled/replaced the plugs. They all looked good to me after 40k. I'll upload a pic if your curious. That a good copy on the horoscope if I can find someone who's got one I'll try it. I may try a comp test if I can find a hand as well. I just drove 400 miles yesterday and I didn't lose a drop of oil, but still saw some blue smoke this morning. Hopefully that means I'm not constantly burning oil? It is also getting into the low teens here if that is useful to know.

 

That 2nd plug, which cylinder did it come out of? All that hydrocarbon buildup after the last thread, and the discoloration of the porcelain, it looks like it may've been burning a little something extra in that cylinder. Did you mark these before you pulled them so you could remember which cylinder each came out of? I typically do that with plugs and coil packs so I can compare later. Here's mine at roughly double your mileage, the factory plugs. I did have some leak-by on the spark plug tube gaskets on cylinders 4 and 6 (middle two, bottom row), but changed the valve cover gaskets at the same time as the plugs. Not sure what is/was up with cylinder 8. I've been suspicious of that coil pack for a minute or two.

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That would be cylinder one yes. I actually noticed that plug seemed a hair loose like I didn't tork it all the way. Leak by huh? What do you mean by that?

 

Hair loose would explain that, yep.

Leak-by, I had some oil leaking past the valve cover's spark plug tube gasket and getting into the spark plug tube itself, and the residual oil and heat mixing together stained the shank of the plugs on (should be obvious) two of my plugs.

The valve covers are notorious for leaking on these trucks equipped with 4.7L, you need (at minimum) to replace the larger outer valve cover gasket, and to have some FIPG so you can pull/reseal the half-moon plugs (2 per head) and two right-angle corners (per valve cover) at the valve cover head. More info HERE.

Anyway, there's more gaskets on a valve cover than just the big one most people would think of. There's also 4 ring-shaped gaskets that seal the top of each spark plug tube, so oil can't leak past the valve cover and reach the spark plug. Those things get hard as a damn rock after 40k-50k miles. Good pictures of them installed and removed HERE.

Needless to say, my truck at around 70k-75k original miles, those gaskets were fucked, the spark plug tube gaskets and the valve cover gaskets. So I replaced them, and posted all the info in that first link. I've helped others replace theirs since, because it's not a difficult job, it's just a bit tedious and takes a couple hours overall. It's helpful to have someone around that's done it before.

 

I see, well I'll definitely have to eye up those valve cover gaskets. Perhaps you are right and the gaskets at the spark plugs are getting old. Perhaps when it was -6 F where I live, the cold temps shrink and allow some oil to seep past? I would like to try and clean my engine first, it's pretty grimy from 23 years of oil changes worth of spilled oil on the valve cover. That way I can see if there are any leaks.

Aside from that, it's been maybe a week or two and I have not seen any noticeable blue smoke. Also, I have put 1000 miles on this oil and do not see any oil consumption on the dipstick. Unless I see any new oil consumption or blue smoke, it may be safe to assume that the aftermarket PCV valve failed, allowing oil to get sucked up into the intake on cold starts. The PCV wasn't fully clogged, but I think maybe stuck partially open. Under the high intake vacuum on startup, oil was likely getting sucked into the intake. That may also explain why I'd see more smoke right after an oil change, as by adding oil I wonder if some oil got into the PCV baffling on the underside of the valve cover, leaving more oil available to be sucked up. Looking into the oil filler at the cylinder heads, I can see a decent amount of varnish and crud, so maybe there is some sludge from the previous owner, and the oil drain backs in the PCV baffles aren't as open as they used to be. This is all speculation based on what I saw. I did see oil in the old PCV and lots of crud in the hose. I will keep monitoring but I think they may be fixed. I think I'll try some of that Valvoline restore and protect to deal with the sludge. There wasn't many miles on the PCV when it got crudded up so maybe some cleaning will help. I see that Valvoline R&P is actually legit at removing deposits without damaging the engine.

So unless I see anything new, thanks everyone for the help.