I went to change out my OEM oil cap with my new NISMO cap and I noticed the inside of it looked like this:




It smells like oil but it's thicker than oil. What could be causing this?

 

Coolant will turn oil that color. When you opened the oil cap, did white steam come out?

 

No, the car has been off all day (6 hours)

 

You have coolant in your engine. It's safe to assume your head gasket is done.

 

Wouldn't I see some drivability problems or some white smoke?

 

yes from my experience, coolant and oil mix give you milky lookin oil. No signs needed such as white smoke or sputtering etc etc. they will come next if they you havent seen sympthoms eventually

 

Hmm maybe it's time for a motor build.

 

dont wait for heavy white smoke or the other tell tale signs. replace your head gasket ASAP before you really fuuck up your engine, or like you said, do a sick motor build.

 

you sir, have a blown head gasket.

congrats!

 

 

What about condensation build up in the valve covers? It's been raining a lot here lately and the humidity had been high. The garage it stays in is kind of damp all the time. Also, the car doesn't get drove much. Maybe 20 minutes a day. To and from work. I don't have this color oil on the dipstick, just on the cap.

 

Yes that would be water.

 

OP, I do not believe that this is a head gasket problem at all. It is condensation. Almost every oil cap I remove every day looks like that on the underside, it's normal.

 

That's what I was thinking. If I had oil in my crank case then I would have a problem. After I left work today I drove it around for about 30 minutes hard and when I got home all the milky oil was almost gone off the cap.

 

You're ok, I wouldn't worry.

 

Can also occur if you have a short drive to work. Still worth a check to make sure compression isn't out, but I've seen a couple cars with the same gunk under the cap that haven't had any issues.

 

Yeah I have like a 5 minute drive to work.

 

the oil cap on my car got like that last time I took a water hose to my engine. Check the dip stick, if its not milky you'll be alrite. like everyone else mentioned it could be condensation.

 

Did someone order a Guinness?

 

Right answer.