YES INDEED,there does develope a slight amount of creamy looking film that looks like coffee with cream,,off white,,light brown, take your pick.
it starts at about 3 miles,increases slightly till about 8 miles and must go away after that,i didnt want to burn up gas to see. just look after a good run. i did yesterday and saw none when hot.

my jeep is low on gas so i just went 2-3 miles, no trace of foam.ill gas up soon and see what it does.

 

this is aces again,thanks for all the replies!I think there is something going on that shouldn't be going on,but what gets me is noooo symptoms.there are defidently cases of condensation in some vehics.let me give you a little more back ground info.I drive about 10 miles to work and back daily.plus evening and weekend use.you can burn oil if not changed regularly it breaks down and can evaporate or whatever.which is what happened to me. I kept putting it off and went about a month over due.I've always been right on that,not this time.which is why I checked oil was 2 quarts down that's when I noticed creamy color stuff under cap and on dipstick above oil full line.got oil change.about a week later my radiator went non-related?good I can get all new fluids.I put a new radiator in and new dex-cool.and changed my oil myself this time with best synthetic oil I could find.got new oil filler cap and all hoping to see no more creamy junk.Sorry there it was the next day.bummer hummer.so I think it' some kind of breather, crankcase vent of some sort.not loosing any coolant and it's still clean.does this engine have a pcv valve or what?if so where is it?

 

happythree, you saw creamy stuff in your Hummer?

 

sorry,YOU said under the cap, thats all i saw, a tiny amount of "cream" like coffee tan color, NOT MUCH, just a trace on the lid and in the fill hole.

no other trouble at all.

oh, i also held my palm on the fill hole and felt a very weak vacume. i then held cardboard to block the fan air and held a tissue over the opening. it barely fluttered but that vacume told me the breather tubing was working,(as best i can conclude) since it also pulls thru the intake/air filter,. that might be worthwhile doing as a test of the breather.

 

Thank you all for your comments and observations. I do feel better now...
I acquired my Hummer H3 2008 1 month ago with 111k miles.
my hummer H3 2008 is now 112kmiles.
Runs fine, no roughness about it.
Coolant is clear and does not vary.
Oil is clear.
Occasional Milky residue under oil cap noted.
Milky substance does not taste sweet.
I do not drive much long distances, just 2 to 3 trips 6 miles to work and 6 miles back, 2 to 4 times a week... at best rest of time I walk/run to work and back...
Noticed milky deposits today which is colder and wet days...we have cold and wet days this time of year...
Spoke to my Mechanic...

So if coolant does not vary, if taste of milky residue is not sweet, what can it be if not water condensation which is trapped up there at the highest level. Besides the nearest breather is way below the top of the oil fill cap... not good but that's how this was designed...
All be it one needs caution and an eye needs to be allocated to the issue...

In air cooled plane engine, this issue is very common but here is air-cooled... for us we have coolant. so let's all keep a watch over coolant and oil...

Any more news on this subject is always a good thing.
Best to all
Pascal

 

Welcome. Please AVOID digging up Old as Dirt NINE YEAR OLD THREADS to tack on a question. READ: Old Threads/'Necro-Bumping' Not the way to ask your simple question.

It is condensation at the top of the motor because you drive SHORT DISTANCES and the engine does not reach full operating temp at all or not long enough to bake out the moisture. GOOGLE it.

THREAD CLOSED.