It's been between -5 and 20 degrees lately and I've noticed that the oil in my catch can is quite milky. This is even after a 60 mile hwy drive.

Is this normal to see during the cold season? If not, any ideas?

My first thought was "Oh ****, I've got antifreeze in my oil. Blown a head gasket.", but it's definately not that.

It's finally been in the upper 20's so I hope it gets a bit warmer (30's) soon so that I can see if this milky residue goes away.

 

i wouldn't think so. especially once it's warmed up after a drive...

 

I have been seeing the same thing. I do believe it is due to the cold. I actually run two catch filters (clear Home Depot type). Normally the second filter collect oil at ~1/4 the rate of the first. Since the sub-0F whether the second catch has filled with a milky brown substance which I believe is at lease 75% water from condensation from inside the engine due to a very cold block. I find it interesting that the first catch collects mostly oil (still slightly milky) and the second condensation.

 

irish can chime in here, but i believe that is really the housing of the catch can that is melting off. there is a warning on the catch can that it doesn't work well with synthetic oils.

that is, if you're running synthetic. if not, then i have no clue what it could be.

 

Castrol GTX 5w30 - It's definately not the plastic deteriorating.

I just wanted someone else to chime in with same issue. Apparently, it is the cold weather.

 

Same thing is happening to me. I had chunks of ice in mine. Is there anyway that there could be a mixture of gasoline in it as well possibly breaking down the oil.