Since more than 6 years I have an ugly oil water emulsion in my oil cap. The oil in crankcase is clean (no water emulsion). After cleaning the cap will have water oil emulsion after 50 mls.

Motor runs perfect.

Any ideas about?

Thx

Andreas

59 F-250, 292 cu Y-Block, gas & lpg fired engine

My 292 will have that too , in fill tube and dipstick tube not in oil. It seems like the cause is short run times not allowing condensation to be cooked off. Long highway cruze took care of it for me.

62 f100 short unibody 292 big back window massachusetts

I'll add. My 292 has been converted to closed pcv system if that matters.

62 f100 short unibody 292 big back window massachusetts

Time to do a pressure test on the cooling system, it will only get worse in time.

Under idle or cruise conditions the outside air is entering thru the oil fill cap, and leaving the crankcase thru the PCV valve and into the intake. The mesh in the cap is oil covered and works as a filter for the incoming air. That cap doesn't get very hot in cold damp weather, and you don't say where you are. If you're somewhere cold and damp like Seattle right now, and you're doing short trips at low speeds, I'd say it's normal. If you're in the sw desert at 70 degrees, different case. I'd think if it's been going on for 6 years you'd know by now if it was a cooling problem.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

After 50 miles I would think its hot enough to stop condensation BUT are you in winter? AS suggested a pressure test could confirm anything else.
attached is the cap off my 35 Pickup  [flathead] I just cant get it hot enough in winter and driving to work is not doing it much good as I have noticed sludge building up in the pan too.




"Came too close to dying to stop living now!"

No details on the engine given, but is your crankcase ventilation clear & working? If there is no thru venting both upper & lower, that may be the cause.. The oil fill cap screen can get clogged with dirt easily & if your engine has the lower canister filter setup, the filter needs to be serviced once in a while..??  


Paul

Hi Paul,

good question. The vent seems to be ok. All tubes and hoses are free. For details see pics.



Oil fill cap to aircleaner



Pcf to intake /carb



View into oil fill tube



My dirty oil finger



59 F-250, 292 cu Y-Block, gas & lpg fired engine

Yes, will ask my favorite workshop, hopefully they don't want to convince me to order a new 292 ... ;-)

59 F-250, 292 cu Y-Block, gas & lpg fired engine

my guess is you do not have circulation. the hose from the breather is competing with the pc valve..if the breather on the bottom of the block has bin blocked you will  have oil accumulating in the v as well. the competition especially when rpm increases.. just my take.