Stuff under oil filler cap...what is it?

[zerosoma]

Not really sure what this is, texted it to my father in law and he says it's moisture, but it's not white... it was like yellowish with spots of brownish red. It collected in the four reservoirs inside the cap. It's on the side of it because I scraped it out with a plastic knife to see what it was. It is not anywhere else, not through the fill hole, not on the screw marks where the cap fits, ONLY on the bottom of the cap where you see in the picture.

Oil was black tonight when drained, not odd colored or milky.

This was from my Prius, it sees highway miles regularly 4x a week, 100 miles each day. Was running QSUD. Now running Mobil 1.

Any thoughts?

 

[fdcg27]

Its the mayonaise that you get from condensation in cool or cold weather.
Maybe not a good sandwhich spread, but not unusual.
If you had taken the car for a good run prior to removing the cap, it would have been gone.

 

[zerosoma]

Originally Posted By: fdcg27
Its the mayonaise that you get from condensation in cool or cold weather.
Maybe not a good sandwhich spread, but not unusual.
If you had taken the car for a good run prior to removing the cap, it would have been gone.


That's the issue though, we just got back from a trip from a town that was 10 miles away on the highway. Maybe that's not enough time or miles to dissolve it?

 

[bourne]

Its a Prius, your engine isnt always running when you are driving. I wonder how many of those miles it shuts its engine off. Perfect application for a high VI 0w20 oil. Faster warm up = faster burn off of condensation. Do you/driver have an easy driving style ?

 

[fdcg27]

Maybe not.
How cold was the weather?
Ten miles may not get everything warm enough to dissolve the stuff.
Rest assured that it's only on the cap, though, not in the engine.

 

[bepperb]

Looks like condensation to me. That's not surprising, 10 miles isn't a very far drive and it's a long term issue, a hour long drive won't make it all go away in one trip. I wouldn't worry about it, happens a lot.

 

[TFB1]

Originally Posted By: zerosoma


Any thoughts?


Douche it out with some brake cleaner and keep on goin'...

 

[stephen9666]

Originally Posted By: fdcg27
Its the mayonaise that you get from condensation in cool or cold weather.


+1

Some cars get it more than others. My girlfriend's beetle gets tons of it under the cap in the winter. Short drives makes it build up faster, from my experience.

 

[Zaedock]

Looks like broccoli quiche.

 

[yonyon]

It's Cap Cheese. To cure it: take an asprin, then drive around for two hours. Get plenty of rest.

 

[morris]

as all ways your dad is right. its moisture. your engine may need a new PCV valve, i say may. they are not expense. its a cheap no brainer. cant hurt.

 

[spasm3]

Originally Posted By: bourne
Its a Prius, your engine isnt always running when you are driving. I wonder how many of those miles it shuts its engine off. Perfect application for a high VI 0w20 oil. Faster warm up = faster burn off of condensation. Do you/driver have an easy driving style ?


This, 10 miles in a hybrid is probably not a lot of engine running time. The consensus on this board is it takes about 20 minutes of engine running time to get the oil to temp

 

[oggb]

Condensation. My Prius never had this even when I was only commuting 3 miles/5-10 minutes to work last winter but it's fairly common across almost all manufacturers.

Nothing to worry about at all.

 

[Seventh]

100mi a day 4x a week I think would be enough heat to evaporate the moisture, but I dunno how much engine run time that translates to in a Prius. If you can see it only on the cap and nowhere else I wouldn't worry too much.

For your comparison, (and for BITOG'S viewing pleasure) here are some pics of a BMW that was brought to me with a cracked head. All you could see inside the filler cap and breather tube was mayo. Same story once the VC came off. Enjoy!

 

[Donald]

Looking at an oil fill cap or down the oil fill hole is kind of like looking at the color of your oil. Maybe interesting, but not a valid method to evaluate the condition of your oil or engine.

Get a UOA and/or pull the valve cover.

 

[zerosoma]

Originally Posted By: bourne
Its a Prius, your engine isnt always running when you are driving. I wonder how many of those miles it shuts its engine off. Perfect application for a high VI 0w20 oil. Faster warm up = faster burn off of condensation. Do you/driver have an easy driving style ?


Yeah, are you kidding me? Once I got our Prius and figured out I could hypermile and get 99.9 MPG by coasting I drive SUPER easy.

Looks like I can sleep well tonight. Thanks guys!