This has been discussed many times before, but I thought I would include some pictures. I noticed a white film on my oil cap today when I changed my oil. My headgasket isn't leaking, I'm not loosing coolant, the PCV valve is only 5 months old, the oil color was normal, nor was their any antifreeze on the dipstick. This is normal during colder weather. It's just moisture in the crankcase rising to the very top of the engine.





Here's a few more threads discussing it.

https://www.f150online.com/forums/sh...=white+residue

https://www.f150online.com/forums/sh...ght=white+film

 

Well, yours looks pretty milky, mine usually if at all looks like a swirl. It is normal condensation thing, apparently not an issue to concern yourself with. One less headache. I had this for a very long time, wipe off and next time may have nothing.

 

Exactly - Same here , I haven't seen all year this time. I use to get a little here and there. Wipe it off and then I don't see it again for quite some time.

KDOT - Is that yours and do you change your oil regularly ? Reason I ask is when they get that milky it means your pickup screen is contaminated - half plugged up . Posting that pic may have just saved you a motor , better check it out .

 

What does condensation in the crankcase have to do with a plugged screen on an oil pump? That's the first time I've seen that film since, well, this time last year, and the same time two years ago. It's not there when it's warm out, it's a seasonal thing you see. If my pump screen was plugged I would expect low, fluctuating or no oil pressure. You see water vapor is a byproduct of condensation. I don't care how good your rings are, there is going to be a little tiny bit of leakage of unspent fuel, water, and other junk from combustion. (This is why it's really dumb to go 8000 miles between oil changes) When the engine is cold the water is in liquid form in the pan. When the engine is warmed up the water is driven off and it rises up the the highest point, i.e. the filler neck. The neck extends a few inches about the valve covers, making it cooler. The water vapor condenses on the neck and cap.

I change my oil religiously every 3 months. In the past three months I only drove 1400 miles. I suppose I could change it every two months or every 1000 miles. I've used Motorcraft 5W30 and then 5W20 (when the spec changed) for the 4 1/2 years I've owned it.

 

Then don't check it then - I don't care.

 

Do you always make unsubstantiated claims about things that are going to fail? To put it another, way can you make a rational argument as to why that white stuff would be an indication that my pickup screen is plugged?

 

Oh Brother - okay here yuh go ,

10 years ago I had an 86 in line six same problem - when it went , that was the problem according to the mechanic - I seen and he asked me if I noticed any milky condensation under the cap - said when the screen start to plug you don't get the flow or as much and more than normal condensation under the cap forms - That's all got for yuh - beside I read it somewhere else - can't remember where , just trying to help - do what you want with it. Yeah , I alway make those statements look it up .

 

Well llike I said it's seasonal. It comes and goes. It's there in the winter, but not in the summer. So I guess the screen gets plugged when it's cold and unplugged when it gets warm.

 

Just make sure you post if the problem progresses.

Thanx

 

the milk shake that you speak of is completelynormal. my 89 F 150 has done it every winter for 8 years that have owned it

 

oil flow and combustion by products have nothing to do with each other!!! what shade tree did the mechanic get his training under?
if your engine is not gettting up to operating temperature, the moisture will build up in cold weather, if the PCV system isn't flowing enough the moisture will build up and if you are leaking coolant into the engine milky film will appear. thats pretty much it!! coolant has three places that it typically gets in the oil 1) head gasket leak. 2) intake manifold gasket leak if there are coolant cross over passages in the intake. 3) oil cooler 4) if it is a GM coolant weepage at head bolts protruding into the cooling jacket.

 

I know people love their trucks but dude, that's just sick.

You need help.

 

He's right though, and I'll tell you why....

When you have really low oil flow, a low amount of volume being circulated, water that condenses in the block and drips into the pan during warm-up and cool-down just sits there. Water sinks to the bottom of the pan, right up against the metal bottom of the pan. If it's cool enough outside, the cold metal will keep the water on the bottom cool enough to keep it from boiling off. Some large globs of water will get picked up by the pump from time to time and pumped up with the oil. When this water hits really hot parts (like the exhaust valve stem) it boils explosively and causes the oil it's mixed with to foam and get milky, this explosive boiling splatters on the underside of the valve covers. With enough driving, enough of this water will eventually boil off as to not leave a lot in the pan, and there's just not enough to milk up the whole oil supply anyway. There's just enough to find it in the heads.

This is also common with all engines operated in cold climates (or just in winter) regardless of the state of the oiling system. A failing oil system doesn't necessarily cause it, it just makes it more common. A properly functioning oiling system keeps enough turbulence in the pan to keep the water from settling so the water mixes up with the oil instead of just sitting there accumulating. Because these very small droplets of water are now flowing through the engine, they evaporate much, much faster. It's not so much a part of combustion byproducts either as it is just due to warm air touching a cold block causing condensation, just like a glass of ice water on a hot summer day. That's not to say that byproducts don't help the process, they certainly do as a byproduct of combustion is water vapor, and it will find it's way into the engine. It has less than nothing to do with the PCV system simply because this process continues after you turn off your engine. The block cools first, then the humidity in the warm engine condenses on the cooling block. If you never turned your engine off, then the PCV system would be something to look at, but considering every vehicle I have ever heard of is turned off at some point, what happens then no part of the engine has any control over.

 

Hey , peace ( :

 

No offense but I'll bs on those oil change intervals. Modern engines stay very clean inside provided they get warm enough to evaporate the water out of the oil. I always go 5000-8000 miles between changes on my 97 and have for at least 150,000 miles. I almost always drive at least 10 miles when I start the truck. You won't hurt anything changing the oil that often, and it may be a good idea if you're only driving 2-3 miles at time.

I also don't buy the pickup screen causing the emulsification on the filler cap. There is no flow of oil in that area no matter what. There is oil vapor and water vapor in that area. In cold weather the water vapor condenses out. The cap is well away from the source of heat and never gets hot enough to evaporate the water. It's no big deal.