We have three 4.7s in our family and all of them seem to get a build up of grunge under to oil fill cap between changes. We run 5w30 Valvoline SynPower in all of them and a Fram PH8A which also adds and extra half quart to the sysetem. All driving is 95%+ highway. I would like to know if there is any way of preventing this or I am hurting my motors.

 

I think for the most part it's pretty normal with our dodges, I run 5w20 and I get a little water/oil/grunge buildup under my oil cap, it doesn't cause me concern one little bit.

-rob

 

Yup, this is pretty much normal. I, like you, was a little concerned, when i changed my oil and saw the beige colored material underneath my oil filler cap.. I use Mobil 1 synthetic, and even contacted them- and the reply was, that this was normal.

 

As everyone states, it's normal. However, being the obsessive compulsive type, I dried my cap out every few days. After a while, I had no more build up. I check it once a month nowadays and dry it when necessary. This seems to be more of a problem in the winter and is worse when I do a lot of short trips where the truck doesn't get fully warmed up.