I just purchased ,sight unseen,a 1998(11/97 actually) F150 2wd from Long Island N.Y. It was driven 400 miles to me by someone else and starts ,runs pretty darn well all things considered. But,upon starting after sitting,say overnight; you have just gotta' see this baby POUR bluish /black smoke out of the tailpipe. You would swear there are no rings in the motor! Aftermaybe 20 minutes of running it diminishes to an almost acceptible smoking and out on the open road it is not that noticible behind you. Let it sit for an hour or more and wowee! It will fill the dooryard and the neighbors also. So.....
- Starts with a few cranks or two and runs pretty darn good.
-Not skipping and idles fine. No surging. Good power out on the road
-Code P0174, lean #2 bank came up,canceled it and has not come back on
-The tailpipe and everything around the rig is covered with a black dry soot maybe a bit oily (seems ,maybe, unburned fuel)
-No oil smell in the smoke (got to be oil tho' I would say)
-Not white anti-freeze smoke ,no sweet anti-freeze smell
-Used 2-3 qts of oil in the 400 mile run and no coolant. (old senile driver brought it back for me so I'm assuming all fluids were proper when leaving NY.
-Compression check today and all cylinders 165 to 175 and blowing oil,gas? out and around the gauge when cranking. (false readings with all that oil &gas? in the cylinders??) Your hand,& gauge get covered w/oil
- long winded internet searches on the famous upper and lower intake gaskets leaking but virtually ALL show coolant problems as they should
- Pulled both intakes today and no visible gasket problem but EVERYTHING,every line,intake,spark plugs etc.etc.is soaked with oil inside of it
-Injectors are probably original,crappy,dirty,rusty. (1 streaming gas??/)
- Obvious PROBLEM! The drivers side intake runner was unhooked from the control valve and the plates were all CLOSED on that side .Other side open of course.
The question ...finally! Is there any way with good compression that the intake gaskets can be sucking oil into the intake manifolds??? OR can that runner being closed somehow create a oil consumption problem??
Sorry for long winded but wanted to be kinda' thorough if possible. Need help on this one for sure! Thank you for now, Gary

 

Yup,I know. Just as I logged off a light came on. It has 217,000 miles on the motor. Sorry.

 

With so much oil in the cylinders as you found when doing a compression test, and the bad smoking after sitting, I would be thinking about really worn-out valve guides and nearly non-existent valve stem seals.

 

WAG: Is it sucking oil via the PCV system?

 

Sure it could! But I 'm not sure how it would do it. I understand the one way function of the PCV valve(which was replaced with fingers crossed,did no good)but I don't know how else oil would get into that system. One search stated leaking intakes AND leaking valve cover thus sucking directly from inner valve cover to the lower intake. No indication of that once part.(but you can really envision it doing just that!) One dilemma is how would rings or valve seals /guides "heal" themselves partially after warming up enough to be kinda' acceptable? Is expansion gonna' do that enough? mmmm....
I have to think there is some huge, weird sucking of oil into the air system rather than rings or valve guides/seals but can't get my head wrapped around HOW.

 

Torn down to the valve covers yesterday so covers come off today and checking seals etc. Thank you for the suggestion. Maybe instead of my thinking of the intake system "sucking", I should think along the lines of the compression "system" pushing the oil into the intake. Or a bit of both.

 

+1 - (and my SWAG) also check the other half of PCV System for blockage. I call it the fresh air side of the PCV System. It typically gets its fresh air downstream of the air filter and dumps it into the opposite valve cover from where the PCV valve lives.


If the PCV System can't get fresh air, PCV valve draws a vacuum in the crankcase and it'll suck oil from anyplace it can.


Does the 4.2 have an oil separator in the PCV System?

 

how about removing the hose from the PCValve.. plug the hose end to keep vacuum loss... run motor and see how much puffs from the PCV...

 

"Does the 4.2 have an oil separator in the PCV System?"
I'm sorry ,I'm not familiar with an oil separator. Could you please explain.
Both intakes off and clean,gaskets had no obvious problems. All runners either oily or wet carbon buildup. PCV line and ALL rubber boots and connections very loose or poor condition. The little "L" boot under the throttle body split in half ... doing nothing basically.
Please don't forget that this HUGE, entire dooryard engulfing, bluegray smoke clears up after 10- 15 minutes to a barely acceptible just smoking pretty good condition.If it wasn't for that kind of "healing up" condition, I would swear rings.Not disregarding the help you folks are giving in any way,just trying to keep it all in perspective. Thanks guys!

 

Motor already torn down to both intake manifold and valve covers off. I did take the oil filler cap off when running and saw/felt no pressure or puffing that was noticable. I wish I HAD checked what you are suggesting tho'. Thanks

 

Valve covers off and peaking in thru' the valve springs. At least there ARE valve seals on all valves. You'd swear some would be hanging there or missing. Heads off today and head gaskets and valve seals replaced. Will check the guides when there, Thank you!

 

A mechanic friend claims he has had MANY 4 cylinder cars that had a leaking(blown) head gasket that was blown only into an oil passage. Hence, no skipping,proper running BUT a pressurized crankcase/oil system with oil blowing everywhere. Maybe,... but that would be a consistant condition. This 4.2 gets better as it warms up. Although,just thinking, is it burning all the oil & maybe fuel in the first 10-15 minutes that has somehow accumulated upon sitting and THEN the almost acceptible smoking running condition is REALLY what it is?

 

I had a V6 4-valve Sable that had an oil separator, like a small canister, in the PCV hose, under the intake manifold. Its purpose is to drain any oil that gets into the PCV hose, into the crankcase, instead of letting it pass up and into the intake manifold.


I'm not that familiar with the 4.2. Maybe it has a baffle inside the valve cover to prevent oil splash from getting sucked into the PCV valve?

 

No oil separator in the PCV lines but ,yes,in each valve cover there is a flat baffle that I would assume keeps splash from the PCV lines. Heads about to come off as of this afternoon. I'm guessing a bullet hole thru' a piston. As sensible as anything else found so far which is nothing upon tear down. What a pain! It is ALWAYS better to find something smashed,hanging,broken rather than a hit and miss guessing game. gary

 

a little more data taking prior to teardown might have helped........ as the motor warms up, the "oil" is more easily burnt and does not show up as well in the exhast.. COLD oil will give off more smoke than a HOT motor burning it................. but your right, if it leaked into a combustion chamber overnight, it would certainly burn more on startup.. but might hydroloc if you have that much oil present.