Hey guys I got a head scratcher here. 04 4.0 5 speed 155k miles

Over last winter I noticed clouds of smoke at start up. No CEL.
The air filter and tube was SOAKED with oil. I changed PCV, changed air filter and cleaned out tube.
No more smoke at start up.

Then this summer I was getting some smoke at startup and sometimes it would smoke a 1/2 mile down the road. It was not consistent at all but I was using enough oil it would foul the plugs and cause a misfire.

So I got a "factory reman" (as I was told from the local ford dealer who sells alot of whole parts), it got a new intake(recommended by the engine builder), every sensor on the engine, PCV, thermostat housing, JBA headers,etc, etc, etc

First oil change was at 1000 miles, no problems.
Then over the the next 3000 miles it used 1 quart of oil every 1000 miles.

I went to shop that installed and they got ahold of warranty company.
1. had them pull plugs to verify burning oil(plugs were burning with oil deposits)
2. had them pull PVC valve and hose(both were dry)
3 had them pull pan and look for debris(small pieces of hard plastic and rubber)
4 had them pull the engine for factory inspection(getting shipped out today)


Any suggestion as to what could be the problem? I used to work in the GM garage years ago but that was well before these SOHC engines were even out.
I am baffled as well is the shop

 

Well there are only 3 ways for oil to get into the cylinders(spark plugs showed that as the problem)
1. intake manifold via PCV or breather
2. failed Intake valve guide seals, several would have to fail for multiple cylinders to be effected
3. failed rings, several would have to fail for multiple cylinders to be effected

Intake manifold is the only thing that can effect all the cylinders if all spark plugs showed signs of burning oil
Be curious to see inside of intake and if it pointed to a source for that oil
There is no oil in the intake or oil passages near it

Its a puzzler

 

It was a new Intake from Ford but there was oil in it, thats i'm assuming how the oil was getting to all cylinders

 

Then oil has to be coming from PCV and/or breather hose, and if it shows up on throttle plate then its mostly breather

Oil vapor in the engine can ONLY be made by "blow-by"
When a cylinder fires some of the HOT gases(exhaust) blows-by the piston and rings and into the crank case, because the gases are so HOT it vaporizes some of the oil on the cylinder walls and sides of pistons
Not other place in the engine runs hot enough to vaporize oil, oil remains liquid in bearings and valve train and just splashes around

The PCV(positive crankcase ventilation) system was added to suck this blow-by out of the crank case and re-burn it in the engine, it IS exhaust gases so is an emissions concern
Blow-by causes a higher pressure in the crank case valve cover areas so "in the old days" it would cause oil pan gasket leaks and valve cover leaks if those areas were sealed
So a Vent was added to the lower block or upper oil pan to vent the blow-by out, and it had a constant drip of oil, lol
Back in those days you ALWAYS had a drip pan under your engine, even if all gaskets were in perfect shape, the Blow-by vent dripped oil
So PCV system was added, no more drips

Also better for the environment :)

But Blow-by is still there, most of the oil vapor condenses inside the crank case but some makes it up to valve area, via the drain holes
Because blow-by creates a positive pressure inside the engine areas the PCV Valve needs to be working well or blow-by and its oil vapor will be forced out the Breather hose and sucked into the engine that way, passed the throttle plate, coating the inside of the whole intake

Blow-by amount is determined by the fitment of the piston and rings in the cylinders, as an engines miles get higher rings will wear and blow-by will increase
A new engine will have about 5% blow-by older engine 200k miles, maybe 8%
You can test cylinder with a "leak down" test
You inject 100psi air pressure into a cylinder at TDC and measure how much of that pressure it can hold, a newer engine should show about 95psi, so 5% loss

Catch cans
Catch cans are usually installed on the PCV Valve hose when an engine has higher miles, but some newer engines need catch cans, because they generate a lot of oil vapor
The catch can has cooler surfaces that any oil vapor can condense on, so as the Blow-by passes thru the catch can much of the oil vapor is condensed so doesn't make it into the intake, then the can is emptied of the now liquid oil as needed
These can be install on BOTH PCV hose and Breather hose

Factory reman 4.0l SOHC engine should NOT have much oil vapor, but if PCV Valve wasn't working then that would explain the oil coating and burning, because all engines have blow-by so some oil vapor, and blow-by pressure would force all the oil vapor out of Breather hose if PCV Valve wasn't working

 

It was a brand new PCV when the engine was installed. It ratted when removed and there was no excessive oil in the PCV or the tube..It used zero oil in the 1st 1000 miles

 

Yes, its a puzzler

But the "blow-by" is the only source of oil vapor in an engine, and it stays in the crank case and valve cover areas, no pathway to cylinders, except PCV system
And if all spark plug tips were effected then PCV or breather would be the suspects

Its possible that all the intake valve guides were left off or failed, but extreme long shot

 

Like I said, they found plastic and rubber in the pan, so that points to valve guide seals to me. ONE plug was not burning oil.
I guess we will hopefully find out next week. it is on its way to texas as we speak for a plant inspection

 

Oops, I missed that part, about the parts in the pan, assembler must have loosened them all installing the springs

 

Engine went to rebuilder in Texas. They did not report what they found but they are warranting the engine. The only problem is they dont have another engine to give me, they are rebuilding mine AGAIN

 

Well. 1700 miles on the "new" engine and I am burning oil and smoke at start up. This is getting OLD

Changed oil at 500 miles and it was full.
Today I started the truck and I got a Big cloud of blue smoke and down a quart of oil

 

Is the intake system as oily as it was the last time?
Same bad valve stem seal supplier?
Did they use cheap rings, young installer?

 

Yes, only two ways oil can get into a cylinder
Intake valve guide seals or piston rings

Pull a couple of spark plugs to see if you can find the offending cylinder, should ONLY be 1 spark plug with darker tip on fresh rebuild

3rd way but a Longshot is PCV Valve, that would mean ALOT of blow-by oil vapor which would be ring issues

 

All valid questions.

I am going to look at the truck a little today

They said they had to "rebuild" my engine and they never said what they found exactly wrong with the 1st rebuild. So I have no clue as to what they did.

it is Another brand new PCV valve on this 1700 mile engine