foam sludge under 4.0L oil filler cap??

Discovered this today while changing the oil on my 2011 TRD OR, 4.0L. See three photos.
I was pretty shocked and worried at first sight. But the oil from the drain pan looked normal, not milky and I didn't detect any oil in the radiator. Truck seems to be running fine.
I am pretty vigilant about maintenance and always change the oil and filter myself. 5W30 full synthetic.
Should I be concerned? What causes this?
Thanks,
Grant

 

http://www.offroaders.com/tech/milky-stuff-under-oil-cap.htm

 

It is just moisture build up. Nothing abnormal but.... looks like it's time to flush the radiator unless that just clean Toyota red. Hard to tell.

 

Yea. Had this last year. Just not running it long enough to burn off condensation. Probably have a short commute. It only accumulates there. Once it warms back up here, hello from Lakewood, it'll go away.

 

Mine did the same thing about a year ago replaced the cap and haven't had an issue. The o ring might be bad and letting moisture in right there

 

Usually flares up in wicked cold temperatures. So for you down in Texas was probably a seal. For cold places, if you don't have a long commute it doesn't have enough time to burn off the condensation from heating up the block. Last year I was making 10 minute commutes and it was there. Now that I'm making significantly longer ones I don't have the issue anymore

 

Good to hear. I'll keep an eye on it. Yes, coolant is clean red. Thanks.

 

Yep, my commute is about 10 minutes. I guess it depends on the engine, haven't had this before on even shorter commutes with other trucks--and that was in humid Missouri. But we do get plenty of temperature swings around here. Love the mountains.

 

Has to do with how far the filler is out from the engine. Stays a lot cooler than the rest of the engine too. Common on the 4runners as well since they are the same set up. I tweaked when I first saw it. So I did my research. Glad I could help out

 

10 minutes is not long enough for the engine to reach a temperature that will burn off the nasty by-products of cold operation--what you are doing is heavy duty operation--so the nasties collect as sludge at the colder reaches of the crankcase--the 710 cap being one:



Take it out once a week and drive 25 to 30 miles (or more would be better) at highway speeds (75 to 85 here in FL) to burn the crap off, and change the oil more frequently than one would under lighter duty use...