1978 ford pickup 150 302 engine?

what causes a yellowish foamy substance to form around the oil filter cap with the filter inside the cap. Also the the crank case filter that sets inside the airbreather has had a build up of the same thing. Does not do this all the time.

Albertaschild2010-02-18T19:49:27Z

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This is condensation forming a foamy emulsion in your oil, when your PCV system is not operating properly either due to a stuck PCV valve or a plugged vacuum line you build up crankcase pressure until it blows this foam out any path it can find (if you look it will probably also be on the dipstick handle and tube) . Replace your PCV valve and if it continues to do this check for plugged/broken/disconnected vacuum lines on your PCV system.

goldwing1279592010-02-15T17:51:21Z

Condensation is noted for these engines. Thy were noted for getting water in these engines. Thy did not have much EPA stuff on them, mostly a PCV valve was about the only smog thy had and thy would stop up all the time.
Changing the oil and putting in a new PCV valve. will fix this.

billy2010-02-15T17:43:19Z

Did you do an oil change recently?
It is likely from water in the oil

sasyone2010-02-15T17:41:47Z

I have seen this on older vehicles and in my mind water is getting into the oil somehow.

Anonymous2010-02-15T17:44:20Z

its condensation......happens more in the winter than summer usually.....can sometimes reduce it a lot or eliminate it by adding extra breather filters....like one on each bank + the pcv valve....