yellow film residue on the underside of oil cap, more info

[Harrison]

Today i was out messing with the car and i took off the oil cap and there is a yellow bubbley like residue on the underside of the cap and on the walls of the pipe running to the crankcase. It has me a bit concerned beacause i've never seen this before on my car or on any other. I changed the oil the other day as well, and at the time, there were no signs of this problem. Checked the dipstick too, and there were no signs of yellow on the dipstick. I run castrol gtx 10w30 as well. Help appreciated!

[ November 28, 2005, 10:42 PM: Message edited by: Harrison ]

[CamaroRob97]

Ive never heard this before.

I can't remember is Castrol made from plant wax, I know quaker state is, I think castrol is.

Maybe it is just the dried residue left on there from pouring?

If you have no problems with the car and the oil in the pan is fine and you have no evidence of anything I wouldn't worry about it.

[iGoRa]

I do have exactly same problem. Yes, there is a leak. Oil is leaking into antifreeze. The funny thing is that its happened to me when I was on Castrol GTX as well. I used antifreeze stop leak and switched to Valvoline max since than. That was a year ago , and now problem came back , nothing very serious. I think that intake gasket is bad (check for wet spots around heads).

[Harrison]

i hope its not a head gasket, how hard is that to fix? being a 3.8 and so cluttered, the difficulty level probably starts at a 5 too :(

[black98V6]

that sounds like antifreeze in your oil. It might not be that big of a deal to be honest I'd clean it up and see how long it takes for the film to come back, it could also simply be a result of alot of short driving and condensation in the crank case not being burnt off.

[Harrison]

It seems as if i have a leak somewhere around the oil pan because there are what seems to be oil stains on the y-pipe from drips. Another thing i neglected to say was that my oil pressure is usually around 65 at idle and between 70-80 while driving, would the higher oil pressure result in having adverse effects on seals/gaskets? I also replaced the oil pressure sending unit about 4 months ago as well, and when it went, it just started leaking bad. I hope someone can put any of these pieces together for a logical explanation.

[Marty85]

Another thing it could also be is that with the increase in oil pressure and everything getting oiled more, more oil may be suspended in the air in the crankcase due to windage. But it could be lots of different things. As said before it could be antifreeze. Or with it being colder now and with short trips the condensation in the crankcase may not be being evaporated away completely and mixing with the oil suspended in the crankcase and depositing the film.

[terminaldegree]

Whoa! slow down here, people.

1. The oil filler neck just has residue from condensation.
2. Forget about the "wax" argument with modern oil. It's not 1968. It's BS.
3. My car has had this since I bought it, and it still has it running Mobil 1 + Havoline Synthetic.
4. I have my used oil analyzed @ each oil change and I have never had coolant contamination.
5. Stop assuming everything is a blown head gasket or failing intake manifold. You're going to give the newbies a heart attack!
6. Your oil leaks are totally unrelated.
7. My car runs at 60-65psi [idle] and 75ish [2-5k rpm] when warm.