Is my Oil Cap supposed to look like this?

[l008com]

I popped my oil cap off tonight to top off and it looked really strange. It looked like the cap and the inside of the filler tube were wet. Not wet with oil, wet with something thinner, like watery. The color was also very strange.
I changed my oil about a month and a half ago, I don't do a lot of miles so its probably just a few hundred on the oil. It's Mobil 1 high milage full synthetic. Everything is running great. But I've never noticed the cap looking like this before? What do you think?

 

[azswiss]

It should not look like that. Period. Check the dipstick; how does the oil look? Clean or milky? Looks like coolant is getting mixed in with the oil (likely from a blown head gasket).

How to Test A Blown Head Gasket In Your Car

 

[Mooseman]

Looks like oil contamination. Check your engine oil and tranny fluid for cross contamination there as well. I'd send a sample of each to a lab for analysis. Since oil is lighter than water, it will float to the highest point, which is the filler neck. By the colour, I'd lean towards tranny fluid, which would get cross contaminated from the cooler in the radiator.

 

[azswiss]

Agree with @Mooseman

 

[budwich]

Certainly doesn't look good. What color coolant are you running? How cold is the weather and how often are getting a "good hot run time" on the engine?

 

[l008com]

How safe is this to drive short distances? Like can I drive it to a shop and back and forth a mile or two each day or should I be getting it towed.

Thinking about if this is a new problem or not, it is definitely new because I absolutely would have noticed a weird color when I drained the oil a month ago.

 

[l008com]

Certainly doesn't look good. What color coolant are you running? How cold is the weather and how often are getting a "good hot run time" on the engine?

No idea what color my coolant is. I guess it looks orange through the reservoir but that could just be stains.

It's almost Winter in Boston so its getting pretty cold out. I've driven in the 20's a few times recently, though it was close to 60 yesterday.

In the winter, my trips are shorter so I don't get it up to temp as often as I do in the summer. And my work schedule is totally random so I might be working 100 miles away or i might be working 3 miles away. No long trips recently. Sometimes I take the long way home just to give it a little exercise.

 

[budwich]

How many miles on the engine?

 

[l008com]

~155,000

 

[budwich]

My guess would be that you have some "degree of blow by" and as a result, "significant condensation" of engine gases are sitting around in your block.... but as others have suggested, you can do some visual checks to see if anything else is showing up.

 

[l008com]

My guess would be that you have some "degree of blow by" and as a result, "significant condensation" of engine gases are sitting around in your block....

I don't really understand what that means?

 

[budwich]

Basically, all engines have some degrees of combustion gases that make it by the rings in the cylinder. The gases endup in the engine oil... they condense as in forms of "water based gunk". Normally, in warmer climates or long run times, the engine is hot enough for those types of contaminates to get burned off via things like the PCV system. However, when the engine never really gets hot enough or the "blowby" is significant, then the "deposits" get deposited elsewhere like what you see.

Again, just my guess but other suggested check will provide additional "symptom signals" one way or another.

 

[budwich]

Looks like oil contamination. Check your engine oil and tranny fluid for cross contamination there as well. I'd send a sample of each to a lab for analysis. Since oil is lighter than water, it will float to the highest point, which is the filler neck. By the colour, I'd lean towards tranny fluid, which would get cross contaminated from the cooler in the radiator.

Not sure how the tranny fluid would cross thru the rad fluid to the engine oil... seems like a "big if". Anyway, certainly a "look / see" to find out if anything is happening that shouldn't be happening.

ADDED: Oh I see what you are saying that rad fluid might have also found its way into the tranny via the cooler. Basically, you are indicating a possibility that his vehicle could have a "shot rad" (tranny cooler / coil) AND a engine gasket failure.... hmmm sounds like time for a new vehicle.

Certainly worth the check but surely not high on the likelihood... would be extremely "unlucky".

 

[l008com]

I have a few updates.

I have confirmed there is no smoke at all coming out of my exhaust after it warms up so that's something.

My coolant looks clean.

My oil off the dip stick looks pretty clean. Its hard to sell because the dip stick gives you such a small sample. Plus this oil is so new, I'm not sure it's even gotten dark yet. I have not driven much in the last month. So it was a little light but I'm not sure thats an indicator of anything. It didn't appear foamy at all.

I brought it to my normal shop but they're a tire shop and they don't do engine work. But they looked at the cap anyway and suggested the problem might be that the rubber seal around the cap has gotten old and brittle and is letting moisture in through there. That seems like a long shot but it was only $8 for a new cap so I figured what the hell.

I drove around for 5 miles, checked the cap, and it was still clean.

So I guess at this point I'll just keep an eye on it. Most of my driving trips are 1.5 miles between two houses. I often go a day or two without driving at all. But then some weeks I may be busy with work and driving all over the place.

 

[budwich]

Thar ya go.

 

[Mooseman]

Oops. I thought that was the coolant cap you were showing so ignore what I was saying about the tranny cooler and fluid.

Yes, that could be condensation forming from the short trips. I'd clean off the cap and the inside of the filler and then drive it enough to get it real hot. If the oil itself looks good on the dipstick, I'd just keep monitoring.