Why the blue smoke?

[K85 Octane]

I understand rings and I understand guide seals, but I don’t understand what’s up with my truck lately. What do you think?

This is repeatable. All in PARK

Start truck dead cold
No smoke

Idles smooth, cooling fan cycles after warm up
No smoke

Rev engine
No smoke

Continue working on garage, come back 20-30min later. No smoke

Bring engine up to 3,000ish rpm, hold, keep holding, start to get smoke, let off throttle, lots of smoke.

Idles again, smoke clears, no smoke. Rev engine, no smoke. But I can repeat the process to cause smoke and will get smoke each time.

My pcv valve is connected. I use a small pod filter in the other valve cover. Haven’t cleaned that is a long while. I don’t thing engine oil is overfilled, but I haven’t checked.

Unrelated, I have a fuel leak in my return line that needs attention. Otherwise I’d take it for a cruise and watch my mirror for smoke. If it’s rings, wouldn’t it be bad all the time?

 

[Wes Harden]

The dirty pcv inlet filter is the culprit. PCV can't get fresh air so it scavenges what ever it can oil mist. Probably sucking air in past a seal or gasket.

 

[imiceman44]

The dirty pcv inlet filter is the culprit. PCV can't get fresh air so it scavenges what ever it can oil mist. Probably sucking air in past a seal or gasket.

I concur.
Rings would seal a gap after warm up so it can't be the culprit if it doesn't smoke when cold

 

[diesel4me]

Could be the oil drain back holes in the heads are clogging up,making the oil take too long to drain back into the crankcase..

Overnight the oil drains down,so no smoke on the next cold start,but after running at high rpms after it warms up,enough oil may be puddling up on the heads to get sucked past the valve stem seals..

A friend had a '70 Impala with a 350 that had the same issues as yours,we pulled off the valve covers (after finding out it had one busted rocker arm!) and lots of oil splashed out when the valve cover was removed,and the heads were slugded up,some oil looked like jelly and we found dozens of aluminum foil seals,that come on bottles of motor oil blocking the return holes!.

It turned out the previous owner was just putting in oil by unscrewing the cap,putting the plastic bottle in the oil filler opening and left the foil seal on the bottle--then just squeezed it to "pop" the seal and let the oil in,to avoid spillage,and the seals ended up in the heads and eventually floated back and blocked the drains....!--since the engine consumed at least a quart a week due to the blocked oil returns,he had to add a lot of oil in a few months time..(the guy sold my friend the car because of it smoking,and he got pulled over a few times,thought the engine needed a rebuild)...it stopped smoking after the foil seals were removed ,some ended up being shoved down into the oil pan,but we used a shop vac after that happened to remove them..