2005 4.0 sohc blue smoke/oil consumption.....

[Dwayneet]

4.0 sohc 102k miles.....large amounts of blue/black smoke when accelerating....removed intake and drained over 1/2 qt of oil...cleaned and reinstalled... installed new plugs....ran great for 20-25 miles then same issue...intake full of oil, smoking when accelerating, rough running random misfires

 

[Curious Hound]

I would replace pcv and get a compression test done

 

[Dwayneet]

Sorry forgot to mention I checked compression when plugs where out....all cylinders 155-160 cold

 

[Curious Hound]

Flip the truck over so the wheels and oil pan are on the bottom.

 

[Roert42]

I know on my 3800 cheby, they were prone to having a upper intake manifold gasket leak that would allow oil to get sucked into the intake at an impressive rate.

I don’t know if that is possible here, but if the compression is good that’s the only way I can see you getting so much oil into the intake.

Even a bad pvc valve shouldn’t let that much oil into the intake. I wouldn’t think anyway. I would replace the pcv anyway, they do get clogged easy.

 

[gw33gp]

I just went through something similar but it was not smoking. The K&N drop in air filter was soaked with so much oil that the engine would hesitate at high rpm and full throttle. The problem was, the PCV valve had fallen out of the valve cover. The little notches that hold the PCV valve in place with the 1/4 turn had worn so much, it could not hold it in place. So much air was sucking through the engine that it was carrying enough oil to dump it in the intake tube and into the engine. When I shut off the engine, the oil would drain onto the air filter. It used a quart of oil in about 200 miles.

I cleaned the filter and oiled it properly. I silicone some thick foam to the firewall behind the PCV hose to hold the PCV valve in place as a temporary fix. I was on an off-road trip and had to do something to continue. It held up while off-road and on the interstate from CO to home in CA.

I ordered a new vale cover but they were on National backorder. It took about a month to arrive and I will get around to installing it someday. The temporary repair is working so well, am in no rush to get it fixed properly.

 

[RonD]

Oil in the intake can only come from PCV system
So thats what you need to check

PCV valve is a negative valve, it CLOSES with high vacuum, and OPENS with low vacuum

At idle vacuum is high, so PCV Valve should be closed or it will suck in oil vapor from valve cover into the intake

Other thing is oil quality
All piston engines have "Blow-by", anytime a cylinder fires HOT gases will "blow-by" the rings, hence the name, lol
These HOT gases WILL vaporize some of the oil coating the cylinder walls and piston sides, this is where ALL the oil vapor in an engine comes from, blow-by, nothing else in an engine gets anywhere near HOT enough to vaporize oil
A good brand of oil will produce less vapor, cheap brand more vapor

Most of the oil vapor will condense inside the crank case but because the vapor is HOT it also Rises(hot air rises)
And it will travel up the oil drain holes in the head and get into the valve cover areas
This is where the PCV valve and Breather hose are
And this is how the oil vapor gets into the intake, thru the PCV valve and/or the Breather hose

You can add a Catch Can to the PCV system, not at all hard to do and a few NEW cars need that, lol
So an older engine can use it as well

 

[Dwayneet]

WOW I never thought a bad PCV valve could let that much oil through....but I was proven wrong again.....PCV valve fixed it...thank you guys