2004 f150 screw lariat 4x4 5.4, was wondering if anybody else has noticed foam in there oil fill cap. i took mine to the dealer twice for it and they told me it is normal because of the moisture from the cold weather. i have never seen this before in any of my other vehicles that i have owned. it is usually a sign of a bad head gasket. the truck runs great except for the big loss in fuel milage, from 15 in town, down to 10 in town. they say that is normal to because of the winter blend gas and the cold weather,and that it will get better when it warms back up. they did the reflash on the pc and that didn't help.

 

I agree with the dealer, which isn't normal for me. My S'crew had some whitish mud on the inside of the oil cap after only 900 miles. I assumed it was condensation from sitting on the dealers lot w/o being run for 2 months, but it was winter time. Changed the oil, haven't seen it since. You may want to take your truck out for a nice long spin with the OD off. Give the engine and the oil a chance to get good and hot, and any sludge in the motor should dissolve. By that I mean off of the cap as well as the valve covers. Driving short trips in the winter time does your motor no favors. After the "hot" run, change your oil before it cools. It can be a bitch when the oil is scorching hot, but more of the nasty crud will drain out with the oil if it's hot rather than warm (or cold).
You'll almost always, if not always get worse mileage during the cold months than the warm. It takes longer for the oil to get to operating temp. so it flows like oil, not gear oil. Personally, my mileage suffers because I let my truck warm up for 5-10 minutes in the winter, as compared to the warmer months, when I just hit the key and go. Don't forget to check the air pressure in your tires too. My pressure drops approx 1-1/2 PSI for every 10 degree change as it gets colder.

SL

P.S. I use only synthetic oil. No petro crud. Don't know whether that plays a role in this situation or not. Just FYI.

 

is this foam after the truck has been running?

If so it could be that the oil has been overfilled.

 

no, it was first thing in the morning, and the dealership had just changed the oil 2 weeks before i noticed it . it wasn't there before because i check it about every 2 weeks to make sure it is not using any. i asked the dealership if they used something different then before and they said it's the same blend oil that they have used the previse 2 oil changes they did. they said they would keep an eye on it. and if it doesn't go away they would do a test on it to see where it might be coming from,other then moisture. it runs like a dream. at least i have it documented if anything happens to it. thank you for your reply.

 

Some condensation isn't unusual. So long as what's on your dipstick doesn't look like a milkshake, you'll be alright.

 

I'm just curious here, but is your foaming coming through the filler cap with it in place, or are you saying you see bubbles in the fill tube only with the cap off?

I agree with the post about using a different oil possibly solving the problem. When I had my PowerStroke, I was told to keep a close eye on the oil foaming, because they use the oil as Hydraulic fluid for the injectors, and foaming caused skipping. The solution was to use anti-foaming agents that you add to the oil, or use such and such brands.

Now with the 04 SuperCrew, I use only full Synthetic, and have never seen any foaming yet.

If your foam is blowing through the filler cap with it in place though, you've got something else wrong.

 

thank you for responding, the foam is in the cap, not on the dip stick. when i took the oil cap it was full of foam. the dealer wiped it off and said it was normal. two days later i checked it again and it was there again. took it back to the dealer and they said they would keep an eye on it, and if gets worse they will run a dye test or something like that. they said it runs to good to be a head gasket. i'm thinking it might gas since my gas milage has dropped almost 5mpg. i think it is pumping more gas then it can burn up. (just my opion)

 

Obviously the 'foam' is from some kind of moisture mixing with the oil. I have never heard of the moisture being bad enough to cause it to come back a day after wiping it off.

But as said above, unless you have the dreaded 'milkshake' on the dip stick (sign of blown head gasket etc..) then I wouldnt worry to much about it. The second you see milkshake on your dipstick (sounds like a rap song,,,, have it towed. Dont drive it unless you want a new motor.

 

I've had this happen on a few vehicles that I've owned. All were 4 bangers with aluminum heads. Whitish foam in oil cap, usually would see it in the colder months. I have not seen this happen yet to my 5.4 L.

My Toyota Camry (2200 4 cyl) does this as well. Like your dealer has said, it's moisture accumulation. If you had a bad head gasket, most likely your engine would develop a miss on one cylinder, very noticeable at idle and your engine would start running very hot. A bad headgasket will also bleed compression into your cooling system in which case, you would start blowing coolant out of your overflow reservoir.

A cracked cylinder head will give you that chocolate milk oil and antifreeze on your dipstick. This is really not a good thing