Oil on top of valve cover, passenger side

[MyExplorer03v8Lim]

2003 Limited 4.6L AWD. 156k on body, 76k on engine.

I've noticed oil pooled in the top bolt locations, on top of my passenger side valve cover. This vehicle has kind of a history, so this is just one small question among a sea of other issues that I'm working through.

At one point I did an oil change at night, and missed the funnel with maybe 1/4 quart of oil or less. It was a few good glugs. Poured it all over the passenger side of the engine.

I cleaned it up as much as I could in the dark, but this was several months ago. I figured whatever was left would just lubricate the area. I have to think that the oil I'm seeing now is new. There's no way pools of oil would reside in that area for long right, it'd just spread out during driving and bouncing around, I think.

So if the oil is new, where's it coming from? How would oil end up on top of the valve cover?

By the way, this vehicle has had a few misfires, and a current vacuum leak that I am tracking down this weekend. Furthermore, the battery refuses to stay charged, so I plan to run some youtube-inspired multi-meter tests on it and the alternator.


Vehicle History, if you're interested:

• Bought in April 2016, inspected by mechanic. Performed oil change. Engine seized on the highway in June, 100 degree day.

• Shop replaced the engine with a mountaineer engine @ 76k. They also charged my AC, but it was empty again within a month. Job finished in August. I believe they kept all of my original wiring, but I am honestly not sure if I have the original or mountaineer harness.

• Replaced front pass CV axle, rear pass tie rod, tires, and rear driver wheel bearing between Sept-Oct 2016.

• Then I started getting engine weirdness. Intermittent loss of power, hesitation, erratic idle, occasional stalling. I had thought vacuum leak, but wasn't sure, so I took it to a shop for diagnosis. They said it drove fine and to wait until the issue got worse.

• (I took it to a Ford dealership most recently, they confirmed vacuum leaks, and I've since done tremendous amounts of research in that area)

• Then I had some misfires. I took it back to the original engine shop guys, they diagnosed a bad coil and two bad plugs. Said there were no other issues and it should be fine. They also recharged my AC but said they didn't find a leak anywhere. They said maybe it just has a tiny imperceptible leak somewhere. (The AC was empty again a couple weeks later.)

• Next week I got more misfiring, as well as lean codes. Took it to a different shop, and they sat on it for a month. They replaced another two coils, an injector, a plug, and a fuel filter. They didn't mention the DPFE sensor, but mentioned that there were myriad wiring issues, as well as a "mysterious backpressure problem". They also said they took of the catalytic converters, inspected them, and put them back on. They did not report any issue with them, other than noting that it appeared that someone had spray painted them silver.

• When I got the car back it drove fine for about 4 miles (guess) and then it wanted to stall at a red light. It lacked power, but got the rest of the way home just fine (.5mi). I made an appointment with the dealer, and that was the next place I drove it. The entire drive it lacked power, and the engine seemed like it wouldn't rev. I would step on the gas and nothing would happen. If I pulled over and sat for a second it would then drive normally again for maybe 100 yards, and then completely lose power.

• The dealer identified that the codes lead to oxygen sensors. They also said someone took an air chisel to one of my oxygen sensors and left visible marks in it, which surely destroyed it.

Here are the current codes:

• P0053
• P0132
• P0172
• P2195
• P2196
• P2197

• The dealer also noted that someone replaced the DPFE sensor with a smaller one, and left it hanging loosely in front of the old one,which is still bolted in place.

• They also said there's a vacuum leak around the intake somewhere, but didn't get specific.

• They said that in general, the wiring is a mess and should be re-routed properly. They also told me to drive it into the dirt until the inspection expires. I felt that they wanted to sell me a new vehicle, so although what they said it probably true, I don't think the vehicle is junk. I'm done taking it to shops, and I am determined to learn to fix this vehicle myself.

I guess those codes all lead to oxygen sensors, and I'm sure I need to replace the one that was chiseled, but this to me seems symptomatic of something other than oxygen sensors.

Based on research/ watching lots of youtube videos, and reading repair manuals,
My best guesses are:

• Vacuum leak (hose somewhere)
• Vacuum leak (intake gasket)
• O2 Sensors
• DPFE (should at least be tested)
• Catalytic converter(s)
• EGR issue?
• Transmission? (pressing on gas, no revving or acceleration)

 

[SyberTiger]

I'm thinking that what you perceive to be engine oil is in fact coolant. You have all the classic symptoms of a leaking intake manifold. I'm guessing you are leaking coolant, it get's mixed in with some dust and grime and has the appearance of engine oil. Further, you said you think you have a vacuum leak. Well, if the intake manifold gaskets are leaking then you could be sucking in air into the injector ports which could drop your vacuum.

The intake manifold is made of a composite "plastic". Over time it can warp, crack and the gaskets can leak. The intake manifold routes air from the throttle body into the injector ports and there is also coolant that crosses over via the crossover on the intake manifold and there are also coolant ports on the rear of the intake manifold. Like you inferred, there is no logical way for engine oil to end up on top of the engine.

This is what I'm thinking. Not only are you seeing coolant leaking evidenced by some of the coolant seen on top of the bolt area that holds the manifold down but you have leaks into the injector ports. Likely, some of your coolant is getting sucked into the injector ports. This will have the effect of destroying O2 sensors and whatever combustion mix of coolant/fuel/air you end up with will clog up your catalytic converter(s) to the point where they will have to be replaced. Clogged cats are notorious for loss of engine power. The backpressure will effectively not allow the engine to rev up. Also note that coolant that seeps down into the spark plug wells will cause the COPs (coil on plug) to short out and require you to replace them. This happens when enough of the coolant gets into the wells.

 

[SyberTiger]

This is what my recommendation is:

1. Check to make sure you don't have the "infamous" rubber elbow rot causing a vacuum leak.
2. Replace the intake manifold. First verify that what you think is oil is really coolant. Do this by taking a Q-tip dipping it in the "oil" and seeing if it lights on fire. If it doesn't want to burn then it isn't oil...it's coolant. Cross verify this by doing the same thing with a Q-tip in oil to compare/contrast.
3. Once you get that done then you can worry about possible clogged cats and ruined O2 sensors. Then you can update us on what's going on.

 

[imp]

@MyExplorer03v8Lim
P0053: Been there, fought it for several months. "Heated Oxygen Sensor Heater Resistance Bank 1 Location 1"
P0132: O2 Sensor Circuit High Voltage, Location Bank 1 Sensor 1
P0172: System Too Rich, Location Bank 1
P2195: O2 Sensor Signal Biased/Stuck Lean, Location Bank 1 Sensor 1
P2196: O2 Sensor Signal Biased/Stuck Rich, Location Bank 1 Sensor 1
P2197: O2 Sensor Signal Biased/Stuck Lean, Location Bank 2 Sensor 1

Sorting through these, first, you don't likely have too rich and too lean at the same time. Second, the trouble lies upstream of the cat. converter, for all codes, Sensor 1.

P0053 can relate to the Sensor Heater resistance, itself, easily checked, or trouble in the wiring harness feeding power to the Sensor's heater. This one cannot be relegated away to the vacuum leak thought.

If it were mine, I would confirm that the O2 Sensor, Bank 1, upstream, shows correct heater resistance, measured AT the Sensor, unplugged from harness. If OK, check harness continuity from Sensor location back to PCM, also to fuse feeding the Sensor Heater. If harness OK, you will be at the point I was after replacing all four Sensors, same code, over and over. I then re-wired the sensor with completely new wiring, same code! The cause finally turned out to be the cat converter!

Berwildering at best. Good luck! imp

 

[drdoom]

How about the PCV valve? Is it OK? On your model year is it on the passenger side valve cover like my 2005?

 

[SyberTiger]

I'm pretty sure it's well known that coolant in the combustion mix kills O2 sensors. If you have a coolant leak and it's getting sucked into the fuel/air mix because of a leaking intake manifold then fix the intake manifold first. Hopefully, if this needs to be done, you can perform the work yourself. I personally have very little trust in the stealership mechanics when it comes to diagnosing and fixing stuff. A lot of them like to play "swap out the components" and let the customer pay for the guess work....and the mechanic you've been using doesn't sound all that impressive either.

Does THIS sound familiar?

 

[imp]

@SyberTiger
With all due respect, I should apologize for my previous post, as I neglected to say you may be right on the money here. So, I do so now. Sometimes I state what I believe, and exclude my thoughts on others' beliefs. Sorry! imp

 

[MyExplorer03v8Lim]

I'm pretty sure it's well known that coolant in the combustion mix kills O2 sensors. If you have a coolant leak and it's getting sucked into the fuel/air mix because of a leaking intake manifold then fix the intake manifold first. Hopefully, if this needs to be done, you can perform the work yourself. I personally have very little trust in the stealership mechanics when it comes to diagnosing and fixing stuff. A lot of them like to play "swap out the components" and let the customer pay for the guess work....and the mechanic you've been using doesn't sound all that impressive either.

Does THIS sound familiar?

Thanks SyberTiger! The information you've provided here is right in line with my research so far, which is why I've been leaning toward the intake manifold/ gaskets.

I've read through all of your comments, and as soon as I have some coffee I'll start investigating. I'm optimistic that I'll find a cracked hose, but to be honest, taking the intake (and associated parts) off this engine might be exactly what I need to do. I'll have a much better chance to check everything over with it all opened up.

I'll perform the q-tip fire test to see if it's oil, which as we both agree, wouldn't make sense. Then I'll fire it up and spray some carb cleaner around the intake.

I'll report back when I've got some more information. Thanks a ton for your thoughtful response and awesome links!

 

[SyberTiger]

@SyberTiger
With all due respect, I should apologize for my previous post, as I neglected to say you may be right on the money here. So, I do so now. Sometimes I state what I believe, and exclude my thoughts on others' beliefs. Sorry! imp

You don't need to apologize. I generally view everyone's comments to be based on their personal experience and so many times it's right on the money. You clearly have a lot more experience with these things than I do. I don't know that I'm right but it does seem like all the problems could be explained by a leaking (coolant and air) manifold as the source of the problems. My input should be viewed as just one more "data point" but not the end all. Hopefully, others will also chime in with their experience go get this issue narrowed down.

 

[MyExplorer03v8Lim]

I just wanted to come back and update this post, since it took such an interesting side track from the original subject.

I finally got around to getting under the vehicle and pulling the upstream O2 sensors. They had broken parts rattling inside. I replaced those immediately with bosche. Unfortunately motorcraft weren't in stock. I would've paid the extra $5 for them. I'll see how long these last.

The vehicle is running perfectly now, and there are no codes. I am very eager to see what my gas mileage is for this tank of gas. The last tank was ~6mpg and the tank before that was ~13mpg.

I say it's running perfectly. What I should say is that there's a slight clunk going from R/D and D/R that will require further investigation. Possible U joint? There's also a slip in the front drivers side wheel while turning at low speed. I feel the vibrations through the steering wheel.

Overall the engine seems to be running very well, though one of these days I'll get around to pulling all of the COPS and injectors, and cleaning/ repairing/ replacing as necessary. And of course I'll have to get a torque wrench for the spark plugs :/

By the way, The water that was sitting on top of the valve covers seems to be staying dry. I blew it off with some compressed air and cleaned it dry with rags, and I haven't seen any more liquid.

In regards to the vac leak reported by the dealer tech, I was totally unable to find a leak. I smoke tested the intake and I am sure I would've seen any smoke coming out. It was sealed aside from the intake box, of course.

So I still have the problem of the wiring harness that I'll have to address, because it's certainly pulled much tighter than it should be in places, and it's definitely sitting on the egr pipe, wrapped in some type of heat fabric. Sketchy.

In conclusion, it's still a project, but for now it's a fun one.

 

[drdoom]

Good job my friend.