How much 'stuff' should be under my oilcap?

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In my 2006 Dodge Charger RT (126k miles), I noticed yesterday that there was a slight buildup under the oil cap. I did an oil change approximately 600 miles ago. I change the oil with synthetic 5W-20 every ~6k miles. The engine sounds great and I thought it was working excellently.

I checked my oil level yesterday. I noticed under the oil cap that there was a slight white-ish color residue on the inside of the cap. I never noticed this before. It easily wiped away with a bit of paper towel. I have never noticed it before, though I cannot recall ever specifically looking before today.

I drove the care for about 40 minutes today and checked under the cap later. It's as clean as when I wiped it yesterday.

How clean should the cap be? Does any white-ish schmutz at all mean that I've got a coolant leak?
 
Originally Posted By: johnnysack
In my 2006 Dodge Charger RT (126k miles), I noticed yesterday that there was a slight buildup under the oil cap. I did an oil change approximately 600 miles ago. I change the oil with synthetic 5W-20 every ~6k miles. The engine sounds great and I thought it was working excellently.

I checked my oil level yesterday. I noticed under the oil cap that there was a slight white-ish color residue on the inside of the cap. I never noticed this before. It easily wiped away with a bit of paper towel. I have never noticed it before, though I cannot recall ever specifically looking before today.

I drove the care for about 40 minutes today and checked under the cap later. It's as clean as when I wiped it yesterday.

How clean should the cap be? Does any white-ish schmutz at all mean that I've got a coolant leak?


Moisture rises and its normal for it to settle on the cap. Very common means nothing.
 
The white mousse-looking stuff is the result of water and oil vapor emulsifying. Probably the result of too many short runs not getting the engine up to operating temperature.
 
Very common this time of year to see this, especially if the engine is run on short trips.
 
Originally Posted By: dishdude
Very common this time of year to see this, especially if the engine is run on short trips.

Yup. Highest point of the engine (often) so moisture and oil vapors accumulate there and cool. Nothing to worry about.

We need one of these as a sticky. I think one of these threads is a daily occurrence during the winter.
 
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Although small amounts of goop can be attributed to short trips in cold weather, there shouldn't be any at all. Realise that if oil and water can emulsify under your fill cap, the same can happen in PCV/breather lines. Run it long enoug to get hot and burn the moisture off, even if it means saving your errands and journeys to be able to do them all at once.
 
It would be a good time to do an UOA if that was something you ever thought about doing. The chances of a coolant leak are unlikely but how concerned are you? [Rhetorical]
 
Originally Posted By: gold01ca
Originally Posted By: Hermann
Yep, it's Mayo season.


+1

Well put!


+2 That's a good name for it.
 
Thank you for the responses. I just read the entire Motor Oil 101 article. Put me in the camp where I used to think thicker oil was better for engines with high miles. Everything I've read or heard over the years has been, more or less, wrong.

I had been warming up my car before driving in the winter, but that article, and the responses in this thread, have inspired me to warm up my car for a longer time before driving.
 
Originally Posted By: johnnysack
Thank you for the responses. I just read the entire Motor Oil 101 article. Put me in the camp where I used to think thicker oil was better for engines with high miles. Everything I've read or heard over the years has been, more or less, wrong.

I had been warming up my car before driving in the winter, but that article, and the responses in this thread, have inspired me to warm up my car for a longer time before driving.


That's actually worse, you can idle for 10min or just drive 1mile to do the same thing.

Also filling in a slightly less general location helps.. Maine might have a different answer than Texas for moisture under the cap.

USA is a far too broad geographic answer.
 
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Originally Posted By: Rand
Originally Posted By: johnnysack
Thank you for the responses. I just read the entire Motor Oil 101 article. Put me in the camp where I used to think thicker oil was better for engines with high miles. Everything I've read or heard over the years has been, more or less, wrong.

I had been warming up my car before driving in the winter, but that article, and the responses in this thread, have inspired me to warm up my car for a longer time before driving.


That's actually worse, you can idle for 10min or just drive 1mile to do the same thing.

Also filling in a slightly less general location helps.. Maine might have a different answer than Texas for moisture under the cap.

USA is a far too broad geographic answer.


Updated.

Not sure I understand how a longer warm up time is worse. What I'm describing is that I would previously start the car, get settled, buckle in, adjust the radio, etc, 1 to 2 minutes would pass then I would drive.

Now, first of all, it's currently -5 Fahrenheit outside right now. So I now open the garage, start the car, go back inside, get my jacket on, etc, and it idles for 5 minutes before I go. You're saying this is worse than the above? In what sense, because it wastes more fuel or is it something else? I truly don't know but I want to have the best habits possible.
 
Originally Posted By: johnnysack
Originally Posted By: Rand
Originally Posted By: johnnysack
Thank you for the responses. I just read the entire Motor Oil 101 article. Put me in the camp where I used to think thicker oil was better for engines with high miles. Everything I've read or heard over the years has been, more or less, wrong.

I had been warming up my car before driving in the winter, but that article, and the responses in this thread, have inspired me to warm up my car for a longer time before driving.




That's actually worse, you can idle for 10min or just drive 1mile to do the same thing.

Also filling in a slightly less general location helps.. Maine might have a different answer than Texas for moisture under the cap.

USA is a far too broad geographic answer.


Updated.

Not sure I understand how a longer warm up time is worse. What I'm describing is that I would previously start the car, get settled, buckle in, adjust the radio, etc, 1 to 2 minutes would pass then I would drive.

Now, first of all, it's currently -5 Fahrenheit outside right now. So I now open the garage, start the car, go back inside, get my jacket on, etc, and it idles for 5 minutes before I go. You're saying this is worse than the above? In what sense, because it wastes more fuel or is it something else? I truly don't know but I want to have the best habits possible.


I'm not an idler, but once it gets that cold, I'll let the vehicle run for 5 or 6 minutes before I take off ,then take it easy.
 
I have the identical car though it's not my winter ride anymore.

I live in saskatchewan. Tends to get pretty cold out here in the winter. Most of the population idles during out cold spells(-40c isn't uncommon before wind) and I personally let my vehicle idle til warm air blows when we get those cold snaps.
Every engine in my work van fleet has very high miles. The lowest is 350k on the odo. None have had any engine work. They idle til warm and are loaded heavy.
My personal vehicles aren't quite as high. The sierra c3 has 220k ish as if this morning. My charger has 80k miles.
I feel it's better to allow the oil to heat up with no load thus easier on the bearings and everything actually.
Sure driving warms up faster but there's now a load which may add some wear.
Not that in the whole scheme of things it matters much. The engines gonna last forever anyway.
My family has many hemi's and my brothers is close to 250k. Runs like new in all honestly. He warms it up before rolling everyday. As do we all.
I'm not interested in freezing solid. And the windows fog real quick at those temps with just breathing.
So I suggest doing whatever's comfortable. In -15 I'll let it warm up maybe 5 minutes before taking off and its blowing warm air. In -40c same deal. I'm writing til it's blowing warm air.
The longer it can maintain operating temp the better in my eyes.
I use 0w-40 in the charger in the summer. Because im a whole lot harder on the loud pedal.
Great car the charger is. The more I drive it the more I like it.
 
in Minn, or places like that the air under the hood is never hot. This alone will make the valve covers cold enough to condense water. PVC can even freeze. I am a big fan of blocking part of the radiator, at least half of it. You will find the heat will work better, the engine will run better and warm up faster. The air under the hood will be much warmer and more water will evaporate. This alone will cure the milky deposits.
Just be sure to remove in the spring.

I do not believe in idle any more than necessary to keep the windows clear. Fuel WILL condense on cold cylinder walls, more so at low speeds and dilute the engine oil and also increase cylinder wear. In diesels this is called wet stacking, and it happens in direct injected gas engines to a greater degree than port or throttle body.

Rod
 
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