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Discussion Starter #1 (Edited)
Hey everyone,

So I was changing a headlight bulb yesterday and while doing so, I noticed a small pool of what seemed to be motor oil at the bottom of my CAI filter. Long story short, it looks like traces of oil are coming up through the PCV or whatever that hose is that runs from the crank case to the intake tube. First thing I did was check my oil level, it was perfect. Next, I removed the intake to check the throttle body for oil, I didn't find in/on the throttle body itself but there some some build up around the lip of the intake tube. There was also oil residue on the PCV itself. I cleaned it all out but now I'm freaking out that my engine is sucking in motor oil through the intake.

After researching, I have gotten mixed review... so people seem to say it a normal thing and nothing to freak out about, others say to replace the PCV. If anyone has any info regarding this, it would be greatly appreciated.

Please note, I currently have a CEL on for the Bank 1 Sensor 1 O2 sensor (Open Loop). Not sure if this could play a part in any thing but thought it was worth mentioning.

Thanks!
 

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Discussion Starter #3
Upon further review, I do not think this is the PCV. From what I have gathered, the PCV is on the back side of the motor... what I am referring to is the small hose on the front side that runs to the the air intake tube. Is this also a PCV?
 

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Small amounts of oil in the throttle body is normal, I don't think it is in the intake, you definitely shouldn't be getting oil in the air filter. Could definitely be related to the CEL, should probably get it checked out
 

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Discussion Starter #5
Small amounts of oil in the throttle body is normal, I don't think it is in the intake, you definitely shouldn't be getting oil in the air filter. Could definitely be related to the CEL, should probably get it checked out


Thanks for the response. Do you know if there are two PCV valves? one in the front and one in the rear? When I search for the part, it keeps coming up the PCV valve for the back side of the motor. The one that I'm referring to is on the front side and is a smaller'thinner valve with hose connected to the intake tube.

Thanks for your help.
 

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Iirc, front side should be the "clean" side. Air is actually pulled in there and circulated through the eng./crankcase and pulled out the "dirty" (pcv/rear) side via vacuum. 95% of the oil/gunk that accumulates in the intake snorkel/air filter/tb/uim comes from the dirty side. 3-5% may come from the clean side. If oil is actually coming from the front/clean side, it's a sign your pcv valve/barb is plugged/gunked or have lost vacuum on the dirty/pcv side and the flow is backing up. I'd replace the pcv valve/barb and inspect for vacuum leak(s). May also consider plumbing in a quality oil catch can between the pcv valve/barb and its vacuum port on the uim. Elite and RX are 2 good brands.
 

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Discussion Starter #7
Iirc, front side should be the "clean" side. Air is actually pulled in there and circulated through the eng./crankcase and pulled out the "dirty" (pcv/rear) side via vacuum. 95% of the oil/gunk that accumulates in the intake snorkel/air filter/tb/uim comes from the dirty side. 3-5% may come from the clean side. If oil is actually coming from the front/clean side, it's a sign your pcv valve/barb is plugged/gunked or have lost vacuum on the dirty/pcv side and the flow is backing up. I'd replace the pcv valve/barb and inspect for vacuum leak(s). May also consider plumbing in a quality oil catch can between the pcv valve/barb and its vacuum port on the uim. Elite and RX are 2 good brands.

Makes sense... thanks a lot for the response. I'm going to start with replacing the PCV (Although this looks like its going to be a b*tch based on its location).
 

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I've looked on my 2016 3.5L Ti-VCT Taurus (that all means non-EcoBoost, non-GDI). Inspired by sheila's input above and confirmed/found the front line is just a semi-ridged tube running valve cover (crankcase air) to the intake (vacuum) - no valves of any kind in this line. It is dark gray color with 90-degree bend. The PCV (6758) is in the backside somewhere, confirmed via Ford parts drawing (attached). I also was going to install an Oil Catch but not sure now. To get a really good effect (I believe) one would need to Oil Catch the PCV line in the back & some sort of Oil Catch on the front tube. As I see it, the intake is normally (if not always) vacuum and therefore the front tube will suck crankcase vapor making the PCV almost moot. So if both the front tube and PCV lines are not filtered (via Oil Catch) there will still be oil-/crud-vapor getting sucked into the intake. Now since mine is 3.5L non-EcoB the injection is multi-port and not GDI. I think that means using good detergent fuel and maybe every so often fogging or other injector treatment should keep the back of the intake valves clean. The Eco-Boost has additional pressure and in-the-combustion-chamber (GDI) injection contributing to gunk formation on their intakes. I just really hate the idea of puke being sprayed in/on the intake & valves, so I'm still considering Oil Catch cans FWIW.
 

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^ Doug, there doesn't appear to be any vacuum on that front line. It looks like it goes from the intake tube to the front valve cover. Fresh air feed. If, after replacing the pcv and checking that its vacuum line/connections are good, you are still getting excessive oil into the air filter, intake tube, tb, uim, etc., you can install an oil catch can between the pcv and its vacuum port on the uim. For the front, clean side, you can install an oil seperator which consists of a replacement oil fill cap with a removable/cleanable filter and a side nipple/port. That front line in your pic is re-routed from the the intake tube to the port on the new oil cap. The port on the front valve cover is plugged off.
 

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sheila,

Correct no "additional" vacuum on that front tube - but the Intake itself is in a vacuum state (low pressure). The engine's piston movement creates lower-than-atmosphere pressure (vacuum) which is how they draw fuel/air mix in - via the Intake. So the Intake is in lower than atmosphere pressure whenever the engine is running. Sorry to be reciting Engine 101 but I need to be sure I'm not missing something. Since that front tube is connected (without any check valves or venturi-valve etc.) between the Intake and front valve cover, and the direction of flow is always higher pressure toward lower pressure, and thus flow would be from the crankcase toward the Intake, right? So that would mean there really isn't a "clean air side" both sides would be dirty crankcase air. So why then does the PCV still exist? The front tube was designed without one. Is the front tube meant to bypass or negate the PCV? I've seen drawings showing similar engine design with flow of that front tube going from Intake toward crankcase but I don't think that really happens. Those drawings show a loop of flow from: crankcase>PCV>intake>tube>crankcase. I don't think it really works like that. Think of the front tube and back PCV line as being parallel because they both connect the crankcase to the Intake. There isn't a lower pressure at the PCV line it is the same as the front tube. The Intake being lower pressure than crankcase, both lines will flow from crankcase toward Intake. I'm thinking the loop drawing is a lie or there is some really unusual odd reason for their premise. But I can't imagine what. If someone knows a reason for there to be two separate lines connected in parallel and one has a check valve in it (PCV) I really would like to hear why/how this is supposed to work.
 

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Doug, front/clean line is not attached to an uim (intake) vacuum port like the rear/dirty/pcv line. Front goes from the intake snorkel/tube to the front valve/cam cover (or oil cap). There is a draw on that line toward the eng./crankcase. Clean flow enters the front and circulates throughout the eng. and pulled via vacuum out the rear along with oil vapor/fumes/crud.
 

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Discussion Starter #12
Doug, front/clean line is not attached to an uim (intake) vacuum port like the rear/dirty/pcv line. Front goes from the intake snorkel/tube to the front valve/cam cover (or oil cap). There is a draw on that line toward the eng./crankcase. Clean flow enters the front and circulates throughout the eng. and pulled via vacuum out the rear along with oil vapor/fumes/crud.

So in that case... Is it normal to have SOME oil residue in the front/clean line as well as the intake snorkel?
 

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The engine pictured is mine. The top red oval is where the PCV line connects to the intake at back of engine bay. The middle oval is the snorkel end of the hollow tube and the bottom oval is the hollow tube connection to the valve cover.

The drawing marked Original was created by someone else, I found it here: PCV system question... - V6Power Messageboard
It basically matches my engine configuration and likely billions of other cars. The drawing is same as zillions of other internet drawings explaining PCV systems. It shows a flow loop as mention previously of intake>clean>crankcase>PCV>combustion.

In the drawing marked Ver 2.0 the green is where vacuum takes place. The whole intake - snorkel, throttle, upper & lower intake manifolds - all under the same vacuum The same amount of draw toward the cylinder heads.

So, in the drawing marked Ver 3.0, if the same vacuum exists on both the PCV and that tube plumbed ahead of the throttle, why do we think air will not be flowing toward the vacuum, toward the intake. I think both lines are being sucked on by the intake as shown in brown. So I think contrary to popular legend, no real "clean air", no real loop of flow through the crankcase. Except for maybe a nano second when the throttle is being opened and perhaps there is a slight pressure difference between the PCV line and the tube ahead of the throttle. But that difference in pressure is very short lived.

All this would explain why the entire snorkel and throttle get coated in oil. It isn't only because of a bad PCV but a consistent flow of dirty air (oily air) up that front line ahead of the throttle. And seems that front line almost negates the reasoning for a PCV valve since the snorkel tube does not have any kind of a valve.
 

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The engine pictured is mine. The top red oval is where the PCV line connects to the intake at back of engine bay. The middle oval is the snorkel end of the hollow tube and the bottom oval is the hollow tube connection to the valve cover.

The drawing marked Original was created by someone else, I found it here: PCV system question... - V6Power Messageboard
It basically matches my engine configuration and likely billions of other cars. The drawing is same as zillions of other internet drawings explaining PCV systems. It shows a flow loop as mention previously of intake>clean>crankcase>PCV>combustion.

In the drawing marked Ver 2.0 the green is where vacuum takes place. The whole intake - snorkel, throttle, upper & lower intake manifolds - all under the same vacuum The same amount of draw toward the cylinder heads.

So, in the drawing marked Ver 3.0, if the same vacuum exists on both the PCV and that tube plumbed ahead of the throttle, why do we think air will not be flowing toward the vacuum, toward the intake. I think both lines are being sucked on by the intake as shown in brown. So I think contrary to popular legend, no real "clean air", no real loop of flow through the crankcase. Except for maybe a nano second when the throttle is being opened and perhaps there is a slight pressure difference between the PCV line and the tube ahead of the throttle. But that difference in pressure is very short lived.

All this would explain why the entire snorkel and throttle get coated in oil. It isn't only because of a bad PCV but a consistent flow of dirty air (oily air) up that front line ahead of the throttle. And seems that front line almost negates the reasoning for a PCV valve since the snorkel tube does not have any kind of a valve.
At least the first and 3rd pic are impossible. Air cannot flow from the intake to the crankcase. Vacuum in the intake. If the PCV does not function in a restricted way, the gasses in the crankcase can back flow to the accordion. There is exhaust passing the rings into the crankcase where it is supposed to be removed by the PCV along with fresh air from the downstream side of the MAF = accordion on any of mine. So, oil in the accordion can come from bad PCV or excess blowby from a bad cylinder.

All arrows to the intake point to the intake.
I did not try to look at the middle pic.
-chart-
 

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This thread is a couple months old but I also had oil in the intake for a while after I bought my 2013. I ended up buying an oil catch can from Ebay, mounting just forward of the coolant reservoir and running a new hose from the forward breather tube to the can. From the can it goes into the intake. Absolutely no oil in the intake after.

I've see videos on youtube that show a new model front valve cover with improved baffles to eliminate the oil in the intake.

Regardless, oil in the intake should not be considered normal. If anything it is an initial design flaw that can be corrected.
 

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I also had oil in the intake when i pulled it to put in new plugs. I ended up removing both the upper and lower intake and disassembling everything. I cleaned the upper and lower, throttle body, K&N intake tubing, and all connectors. This is indeed an unacceptable level of oil, likely from a little blow-by which caused the PCV to vent oil vapors into the upper intake. There was oil pooled in the upper intake and coated pretty decently in both the upper and lower. I opted to replace the PCV with a Motorcraft EV257, even though the old PCV was still functioning just fine. I picked up some oil lines at my local autoparts store and overnighted a baffled Morimoto catch can. The baffles are important as this is what separates the oil and allows clean air to be passed into the intake. Since installing the catch can and fully cleaning the entire intake assembly I have not had any oil back in the intake (going on 10,000 miles since). My mileage went up 2-3mpg after this, but this is likely due to a combination of clean air, plug change, and cleaning the intake runners all being done at the same time. Mounting your catch can between the coolant tank and the strut tower is one of the best locations as it reduces the length of hose from the PCV valve to the catch can, and also provides a straight shot back into the upper intake. It seems that the upper intake is pretty well designed, just needs to be kept clean... however, the lower intake is a choke point and would benefit from some port matching and polishing. I will be undertaking this and reporting back on the results once the weather warms up a bit, Wisconsin gets cold this time of year.
 

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This thread is a couple months old but I also had oil in the intake for a while after I bought my 2013. I ended up buying an oil catch can from Ebay, mounting just forward of the coolant reservoir and running a new hose from the forward breather tube to the can. From the can it goes into the intake. Absolutely no oil in the intake after.

I've see videos on youtube that show a new model front valve cover with improved baffles to eliminate the oil in the intake.

Regardless, oil in the intake should not be considered normal. If anything it is an initial design flaw that can be corrected.
The 3.5's in the 2011-2014 Edge's also have a redesigned valve cover available to prevent oil from getting to the throttle body. http://www.fordedgeforum.com/topic/23145-2011-edge-valve-cover/
 

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I also had oil in the intake when i pulled it to put in new plugs. I ended up removing both the upper and lower intake and disassembling everything. I cleaned the upper and lower, throttle body, K&N intake tubing, and all connectors. This is indeed an unacceptable level of oil, likely from a little blow-by which caused the PCV to vent oil vapors into the upper intake. There was oil pooled in the upper intake and coated pretty decently in both the upper and lower. I opted to replace the PCV with a Motorcraft EV257, even though the old PCV was still functioning just fine. I picked up some oil lines at my local autoparts store and overnighted a baffled Morimoto catch can. The baffles are important as this is what separates the oil and allows clean air to be passed into the intake. Since installing the catch can and fully cleaning the entire intake assembly I have not had any oil back in the intake (going on 10,000 miles since). My mileage went up 2-3mpg after this, but this is likely due to a combination of clean air, plug change, and cleaning the intake runners all being done at the same time. Mounting your catch can between the coolant tank and the strut tower is one of the best locations as it reduces the length of hose from the PCV valve to the catch can, and also provides a straight shot back into the upper intake. It seems that the upper intake is pretty well designed, just needs to be kept clean... however, the lower intake is a choke point and would benefit from some port matching and polishing. I will be undertaking this and reporting back on the results once the weather warms up a bit, Wisconsin gets cold this time of year.
jstenold,
Do you get oil or sludge in the catch can and how much of either?

I quit my catch can project I was planning because I theorized I'd need one on the front line and a separate one on the back PCV line to be truly effective. Since my 2016 is still under factory warranty, I didn't want to get into adding all those hose runs and monkeying up my engine compartment. I'm guessing mine may have the newer baffled valve cover(s) which is another reason I slowed down on the project.
 

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My 3.5L engine has 143,000 miles. The inside of the lower intake manifold runners are quite oily and black in color. The engine uses no oil whatsoever--Motorcraft semi synthetic 5-20. Why?
 
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