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Coroded Swiss Cheese Oil Cap

3K views 34 replies 14 participants last post by  scha0786 
#1 ·
My Oil cap is corroded and looks like Swiss Cheese. I think I need to just change it, but looking to see if anyone has insight to this.

Best I can tell through searching is that since I have put it on the battery when it is removed, acid got on the cap and during my trip to Vegas finally had it and popped. The other pictures show where the cap looks like it went over the turbo. The gunk on it is pretty solid. The third picture shows the bottom of the cap. Seems to be a pretty good design, at least because the lid is a different part then the bottom cap, so nothing went down the oil tube. An internet search turned up a few hits with a similar problem.

I will simply purchase a new cap and keep it off the battery.
 

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#3 ·
Never seen that before.

You're theory is the best I could dream up. Must be a difference in the type of plastics used from the battery to cap???
 
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#4 · (Edited)
I've seen a few like this and not just on 6.0's. Not sure what causes it, but you are not the first case. Mines nowhere near what yours looks like, but I can see some disfiguring on it that really shouldn't be there.

Edit: Didn't catch your turbo pic to start with. That is weird.
 
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#5 ·
The technical term for that is freaky deaky... It looks like something out of Aliens.
 
#15 ·
It's got me curious enough, I'm going to try that tomorrow. I'll put it in a shop corner for a month or two and see what happens. Just a couple of drops. Maybe a couple more in a few weeks. I'll post a picture later this spring or summer, or if something happens sooner.
 
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#9 ·
It looks like it's more concentrated on where the yellow paint coloring is. Wonder if the acid reacted more so with the chemicals in the color for some reason.

-jokester
 
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#10 ·
#14 ·
Aluminum doesn't do too well in sulfuric acid either:

Sulfuric Acid (<10%) D-Severe Effect
Sulfuric Acid (10-75%) D-Severe Effect
Sulfuric Acid (75-100%) D-Severe Effect

Those caps are sure nice though.
 
#11 ·
Different plastics react differently to acids. What I'm really wondering is

DO YOU HAVE A WOODPECKER UNDER THE HOOD????? :hehe:
 
#12 ·
@ChrisSki,

What is that brown stuff on the turbo shield in the first picture?
 
#17 ·
I'm not sure what the brown stuff was on the turbo other than it is this gray stuff that got on the turbo pedestal and melted on top of the EGR. The hotter temps of the turbo baked it brown. I can't think of any tool I used that was plastic that got left in there and it does not look like it came from the old oil cap.

I'll try the acid on the cap to see what happens
 

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#18 ·
I looked under the hood because on the 300 mile drive I was on, the ECT reached 225 and the EOT reached 220. I also noticed when idling at a light around where I live, the ECT reached 220 until I got moving and the temps drop to normal. I'm starting to suspect that the water pump is going bad. When I opened it up, I saw that. 1000 miles ago I had checked the oil cap and it was fine. I suspect that the battery acid on the cap somehow got activated by the elevated temps to turn my cap into Swiss cheese. None of the temps I have on my Edge are out of Ford tolerance EOT < 254 and ECT < 234, but they are getting up there, especially with temps 85-90 and those temps coming from where they get cooled down, who knows how hot it is going into the cooler. Could also have been caused by the melted plastic thing, but no one has been at that part of the turbo in 10k miles.

I put a picture of the battery which does have acid visible at the seal. I also put a picture of where I put the acid on the cap to check it later.
 

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#20 ·
For me, the shop that had it 10k ago added transmission fluid. I have not added that myself. I really don't know what caused it, but I did put the cap on the battery and when I cleaned the battery yesterday, it had been leaking and out of all the cells in both batteries, I had to pull water out of one cell. The only thing that has been different with my truck is the temps for water and oil have been abnormally high for my BPD air cooled oil cooler at 220 down the highway and for the radiator reaching 220 idling driving around town. This started about 1000 miles ago, which before that the temps were normal. Perhaps once I get the new cap on since the new cap does not have holes in it, the oil temps will normalize. The old cap had holes so it could no longer seal the air from the passenger side valve cover.

At this point, the few posts I can find with people that had that problem with the swiss cheese cap was not a pre-cursor to a catastrophic engine failure. Seems to be just something one can expect from 12 year old truck. I have a Dorman cap $6 on it now, and I've ordered a Ford OEM cap $15 that I will have on it by Monday.

For those that do order a cap, the part number in the catalog was a oil filter cap. So when I called into my local dealer and picked it up, they handed me an oil filter cap. The parts tech went and talked to the manager and he pulled up the same part#, but they changed one of the letters to an "A" and that's what I'll have by Monday.
 
#21 ·
I'm sure you already know what water pump and fan clutch to put on it.
 
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#22 · (Edited)
I took a pic of my cap today. Like I said, nothing like yours, but still pitted.


Not sure what the PO might have done, but I'm pretty sure I've never put mine on the battery, nor is there any residue on my batteries. I usually lay mine in the front "tool tray" when I change the oil.
 
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#23 ·
I'm taking mine out for a drive tomorrow to see how it does. I don't know if my cap was pitted or not, but it certainly had no holes. The OEM cap came in at the FOrd dealer today. Ended up being $10 even.
 
#27 ·
mine did the same thing, not as bad as yours but I just bought a new one and will have to check to see if its doing it again.

I put my cap every where under the hood, one time I forgot to install the cap and drove for a whole week like that, lol. Opened the hood and saw it laying neatly on the battery.
 
#29 ·
I lost the part number, but I do remember the A in front and the B at the end. It was a little over $15 listed, but got it for $10 with a discount at the local Ford store.

I put the new cap on and also noticed I was a half gallon low on coolant. No sign leaking from the cap. After adding the water to the degas bottle, the temps for both EOT and ECT have stabilized.
 
#30 ·
just checked mine last night, no pitting yet.
 
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