Oil filler cap "foaminess"

Hoping someone can enlighten me. I was changing my oil this past weekend, and I noticed some "orangey-colored" foam inside the oil filler cap. I hadn't really looked at its underside before, so this kinda took me by surprise. I know I didn't put it there--any ideas? Thanks, Lance.

i have the same thing but mine is a white color, i think this is due to the mioster that collects on the inside of the oil tank due to the humidity, but i could be wrong on this.

uh-oh! you have coolent in your oil!
So glad the coolent is air. I think Fred's got it. The oil cap is a relatively cold place so the moisture in the system likes to condence there.

If you have a water pumper I would suspect a leaking head gasket which allows coolant to mix with the oil. You don't want coolant circulating in oil passages.

You can also get this symptom when you don't warm up the engine before shutting it down. Moisture from the combustion process doesn't have a chance to evaporate which leads to H20 mixing with acids and carbon to form sludge, a creamy black or light colored goo (for lack of a more technical term). A bad case of this can inhibit heat transfer, clog oil passages and decrease engine life. If it's normal condensation in the sump, make it point to completely warm up the engine (and it's 9-12 qts. of oil) before shutting it off.

Sherwood Lee
http://members.rennlist.org/911pcars

For background, I've got a high mileage (145k/’88) daily driver with the same issue. I do use a bit of oil as well (didn’t know I was buying a 2-stroke, I use about a quart every 700 miles).

I drive a 10-mile commute that often doesn’t get the car warmed up. Of course I could drive a different route .

Seriously though, given that I do have a short commute and this is part of the life my car is living, should I worry about the condensation? Am I doing anything to the car that will hurt its longevity (knowing that it is a relative term for a car with 145k on the clock)?


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Steve
88 Targa

Well at least you don't have to mix the oil with gas. . . Unless you have a 72 where the gas station attendants just might mix gas with your oil.
I suppose it depends on ambiant conditions and how you drive, but I would call mine "warmed-up" after 10 minutes of driving.
. . .I live in the always wet NW

Had a friend call me in a panic a few years with the "foam on my oil cap" problem. He was ready to overhaul the motor...

Told him to take it on the highway (the Avus) and after the oil was warm take it up to speed for ten or twenty minutes...

Called me back in an hour. Not only was he very happy (driving fast does that to many of us) but the foam was gone. He did only "stop and go" driving and it was moisture in the oil from its not coming to operating temp often enough.

Take the car out and drive it on the highway a while... good for the two of you! Takes care of the foam as well!

JA

It's the by-product of combustion (in the form of good 'ol water) that is emulsifying your oil. Probably contains some nasty acidic crap as well. Not good for the motor's long-term health.

As previously mentioned, you need to drive the car harder now and then to boil off this water. And with around 14 litres of oil in circulation, it takes a while to get it good and hot. If you have to do a lot of short, cool trips, I'd change the oil a lot more often.

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Doug
'81 SC Coupe (aka: "Blue Bomber")
Canada West Region PCA
members.home.net/zielke/911SC.htm

I come back after a few hours, and look at all the responses. Fantastic feedback. I probably should've mentioned that I have a 1988 911 Club Sport with 60,000 miles on the clock, and ruled out the coolant issue. I work at home, so I often take the car out for short bursts (any excuse, such as returning a DVD). I also live in the cool NW, so I'll have to make a point of going the long way around in the future. Best regards from a somewhat relieved 911 newbie.

Damn,I hate going the long way...

Adam

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1978 911SC 3.0
roseneck@cyberbeach.net

I have experienced this same problem consistently over the past 12 years with my '77. It never seems to matter how hot the engine gets, I still get the milky deposit.

Infrequent driving seems to make the problem worse. That's the good news, 'cause you need to drive more oftern.

Oddly, this never happens on my '86 with the same driving patterns and the same environment.

My engine doesn't seem to be hurt by this, so I just wipe off the cap and put it back.

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Chuck - '86 Cab, '77 Targa, '85 toyota 4wd rain mobile http://www.cheaterswayside.com/911/

everybody knows you take this shmutz and rub it on your bumper bearings!

And here I thought it was the ATF I accidently addad to my oil!

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Joshua Harrison
1968 912 Coupe