Hello everyone. First time on the forum. I am inquiring information about our ford trucks at our landscape company.
For today, I could use some help with our 2017 F-250 6.2 GAS with around 130k miles.

So around august/September, the truck broke down on the highway. Towed to a shop, misfire codes, they determined it was something beyond the coil pack/sparkplug. So they replaced the valve cover gasket.
Truck was towed to the Ford dealership.
from paperwork-
"found cyl misfire on cyl 5. Relative compression was low on Cyl 5. Removed the valve cover and inspected the valve train. The intake spring was broke. Removed the valve spring and installed a new spring and keepers. Installed two new plugs on cyl 5 and a new coil due to the coil arching. Cleared the cam and completed the misfire reset. Test drove. Check engine light has come on removed and replaced HEGO sensor to correct concern.
they also replaced all 16 plugs
total price was $2692

truck seemed good. Then the next month, the CEL came back on. Brought it back to ford.
here's what the paper word said for that-
"Diagnosed vehicle to verify customers concern found Converters are bad NEC to replace converters at this time customer has declined repairs at this time. Estimate for repairs $2815"

All of this was within a month or so. So we just kept driving the truck. the CEL light hasn't been on since then.
Truck has been driving fine, no issues.

Fast forward 5/6 months to today. Check engine light is back on. Check the codes, Cyl 4 misfire and Cyl 8 misfire. For some reason Cyl 8 seems to stay when you clear codes.
I just started troubleshooting this yesterday. I was gonna do the coil switch around and see if code follows.
I pulled cyl 3 coil, had like a 1/2 inch of oil at bottom of plug. Yikes haha. Pulled Cyl 4 plug and it was covered in oil a few inches on the coil. The oil on cyl 4 was like a sludge?/oil water looking mess. I took pictures.
Also wanted to note that the left side of engine cyl 1-4, all along where coils go and where the fuel rail is, there seems to be some oil residue. The right side(driver side) the area around coil packs and fuel rail, is bone dry, no oil residue.

So a quick recap.
-truck has had cyl 5 intake valve replaced
-all new spark plugs
-new coil pack on cyl 5
-valve cover replaced (both sides I believe)
-HEGO sensor replaced (no idea what that is lol)

-and supposedly the converters need replacing

So I've come to the people! haha any idea on where to start next.
Im thinking, it's possibly the CCV or PCV (not sure the technical name for ford trucks) the crank case ventilation.
I have a BMW im currently working on and it has a bad CCV which caused oil sludge on oil oil cap, and it caused oil in the coils.
SO it seems like that could be a culprit. Problem is I have no idea where it's at on this f-250. Ive looked online but it only shows it for the Powerstroke trucks. So maybe our truck doesn't have one? any info on that would be great.
Im also thinking it could be some sort of gasket, either valve cover gasket?(less than one year old) or possible the intake manifold gasket(never been replaced).
What about spark plug seals? could that be a reason?
If not either of those, then it could be another Valve spring? and the way to check is with a compression test?

thanks so much for any information. I really appreciate it.

And for a repair manual, i notice the HELM is top rated, and the ALLDATA one is like half the price. Im not a master mechanic, getting to the valves and what not might be beyond me at this time. So would the cheaper manual be helpful at all? haha or just bite the bullet and get the HELM.

thanks agin

cyl 4

cyl 4

cyl 3

 

Goodness, out of 235 people not a single reply....
well here is an update..

I started to disassemble to get to valve cover, pulled the coil packs, number 2 had what looked like moister around the boot, 3 had oil up to half inch on boot, and 4 had oil ups to the electrode on boot.
The spark plugs, #1 was dry, #2 was okay looking, #3 and #4 were covered in oil, like dripping when you pull the plug.
Then I started looking at the fuel rail, it seemed the leak was more around that area, not around the valve cover like I first thought. so I pulled the fuel rail up, check the pictures. They were covered in oil gunk.
I did not see a crack on the intake manifold.

So what the plan is today, replace PCV, replace 4 plugs, 1 coil boot, and I was thinking since the fuel rail is off, to replace the O-rings. But would like a second opinion.

Any advice on how the fuel injectors, coil pack and spark plugs, On one side of engine, gets full of oil??

anyway, maybe this will help get some feedback..

 

Was everything dry at the time of the valve spring replacement?

 

Now if you came here with a question about fuel mileage or messaging seats or heated steering wheel or even what type of oil to use you would of had 3 pages of replies by now.

A real technical question you come with and us peanut gallery contestants sitting on our hands ignoring the new guy in the room.

I wish I knew more of internals of the engine to truely assist but troubleshooting, I would start with was too much oil added at anytime? The oil on the one side of the engine and not the other seems to show it coming out of something and even with air/ fan movement blowing it around somewhere it should show some area that is "cleaner" than the rest to possibly pin point a location.

With the oil on the plugs and engine how low was the oil on the dipstick ?

 

If you have that much oil in your combustion chambers, you likely might also have burned up a catalytic converter. Still, if it isn't causing a flow restriction it is a minor concern.

PCV system might be a good place to look as for the source of the oil. I don't honestly know if the 6.2L has oil passages in the intake manifold. The older Triton engines have issues with cracked intake crossovers that can cause issues, but I think those were more associated with coolant leaks.

 

From what you've posted (thank you for all the detail) the valve cover gasket is leaking and bleeding down to the valley of the engine. PCV can be a culprit and cause of leak but seeing as the valve covers and gaskets had just been replaced my bet is valve cover gasket fault. PCV valve is on back side of passenger valve cover if you want to check that as well.

To add a bit more info and give a direction, the causes that would put engine oil in those places are as follows.
1. Valve cover gasket fault or installation fault (you mentioned both valve cover gaskets replaced not long ago).
2. Clogged PCV valve causing valve cover gasket failure.
3. Crack or hole in valve cover itself.
4. Crack or hole in cylinder head itself.
5. Someone missed the fill port terribly when refilling engine oil.

 

Wow, that's a lot of oil everywhere. Agree on the PCV restriction or pressure in the crankcase......the valve cover gasket is probably leaking but I'd bet money it's not caused by a bad gasket.

The PCV valve is in the passenger valve cover, however there should also be a dummy PCV valve in the driver's side cover that is just a hollow tube.

 

Couldn't you get an idea on possible crankcase pressurization/lack of venting by removing the oil fill cap with the engine running...to see if it's pressurized or pulling a vacuum?

With all that oil around the plugs, corrosion on the connections probably wasn't an issue...

 

It looks like you need another valve cover gasket and possibly a new PCV. Regarding your previous issues, the 6.2 valve springs don't like to be revved much over 5000 RPMs for a long periods of time. I tried to keep mine at 4500 RPMs or below when towing on long pulls. If you didn't change you're plugs for 130,000 miles would be the reason your cats failed. The 6.2s need the plugs changed at around 90,000 miles or they will kill the cats.

 

WOW thanks for all the replies.
The oil was recently changed from our local mechanic shop. Maybe like 1-2 weeks ago. Maybe they didn't notice anything in the oil, maybe they didn't even look. Its obviously more beneficial to change the oil yourself, we just have like 5 trucks in our company, I just kinda jumped into all this, and getting the oil changed at the local shop is just the way things have been ran. Im trying to change that.
anyway..

So today, I replaced the O- rings in on the Fuel Injectors. I mean I had them pulled out, they were all gunked up looking, so I figured why not?
also I tried to clean the best I could the fuel injector hole/ports. where the injectors sit, it was full or oil gunk or oil/carbon idk (see pictures)

Yes I still think y'all are correct, the Convertor/s are bad. The ford dealership said so last year. So once I get it back together the convertor will be the next job.

Yes it is a landscape truck, pulls a trailer with mower and all that, I will definitely watch the RPMS.

​​​​​​​thanks for all the tips and info! I really appreciate it

​​​​​​​Next I took the valve cover off and replaced the gasket. Where the gasket sits on the engine, two spots like directly across from each other, the gasket look like it was melted a little. I scraped the whole valve area , but those two spots were thick with gasket residue. (see pictures)
​​​​​​​Next I cleaned the spark plug ports then installed new spark plugs.
Installed New PCV valve.
Installed new coil pack for number 4.
then....
on the final tighten of the valve cover, I broke one of the bolts.... I know, its recommend to replace all valve cover bolts when doing the gasket.... obviously I did not follow the guidance lol
believe me I learned my lesson tonight haha. Always get new bolts/washers/gaskets for valve cover! I knew this 15 years ago, and here we are.
And to use a TORQ WRENCH!!! that's what I get
I will update this thread once I get the valve cover bolt out... which is going to be fun.

 

see the two spots where the gasket was.. weird


This is the rubber gasket that melted? or whatever happened here

check out the brown residue that's like only in the front part

oil fill cap, has that brown sludge residue stuff, it was all underneath the valve cover as well.

o ring with gunk all around it


fuel injector port.

 

Just an FYI. Those two spots with what you thought to be melted gasket are actually where the cylinder head meets the timing cover. The gasket was not melted, its actually proper practice to apply gasket maker to those spots prior to fitting the complete valve cover gasket. If you cleaned too aggressively and didn't apply gasket maker those two spots will leak oil as they are the start of a vertical seem and the horizontal valve cover gasket wont fill in that seem.

Same can be said for the guy before you who replaced that valve cover gasket and that spot on the top/inside to engine edge of the cylinder head is a leak point that would put oil right where you have your current problem.

 

Oh okay, that makes a lot of sense. I have to take the cover back off now to remove broken bolt so I will apply some RTV or gasket makers in those two spots.
thank you