I did a periodic oil check today and upon taking the cap off the filler, I had a WTF moment.

Seems there was a thick "foam"? all over the bottom of the cap and inside of the filler. Think of the head on a Guinness and that'll give you an idea of the consistency - but it was thicker.

I've been running Amsoil Extended Life 5W-20 Synthetic Motor Oil (XLM) for the past 10,000 miles (change intervals are 15K). I've never seen anything like this before.

Anyone have any ideas what could be causing this?

(The "line" in this photo is from running my finger across the bottom of the filler cap.)

 

Check the PCV.

Do you do a lot of short trips? Its condensation mixing with the oil. If you go for a long drive it might clear up.

 

On the 4.7 it's been doing it for years. Dodge did have a TSB or something, all it was was a baffle to hide what you're seeing.

It will burn off on a long trip.

The problem is the piece stays cold. Moisture condenses on it and the oil turns like Guinness (good analogy.)

 

Ok, cool. Thanks for the reply. A quick Google search and sure enough, it's a fairly common problem.

I replaced the PVC just last summer. So that should be OK.

It's been an unusually cold December here on the Front Range (Colorado) so based on what I've read, nothing to worry about, but I'll keep an eye on it.

Thanks again!

 

completely normal during the winter. its the short trips when the engine isnt warm enough.

 

That's a sure sign of winter time colder air and short trip driving. While you're cleaning all that crap off, reach inside the filler tube and pull out the baffle inside...the thing with the tab on it. It may take a little effort be it does come out. You'll probably find a lot of crude and crap coated on it so clean it all off and place back in the filler tube. This will help the PCV valve do a better job of ventilating the crank case.

 

This topic has been covered 1000 times. Next time search.

With that being said, its fine.

 

Well, I did search, but since I didn't know what the heck I was searching for, I didn't find the answer (or a picture). Therefore, I post and get great help. It's appreciated. ;-)

Secondly, the "short trips" thing. What would be classified as a short trip? I have a 30 - 45 minute commute (25 miles) Monday - Friday and the grocery store is at least 12 miles away. In both cases, the engine usually reaches normal operating temp.

 

I consider short trips less than 10 miles.