It seems a little murky to me but I have a habit of vehicular paranoia.

Today my engine (22re) was rattling, which I think was pinging, under load on the highway. I wanted to be sure my rattling wasn't the timing chain, so I took the valve cover off to look at the guides. The guides were fine, but the oil looked a little murky to me.

Now I'm worried that it was pinging due to overheating due to coolant in the oil or something. I can't be sure. I don't know what my oil is really supposed to look like. This oil has 250 miles on it.

http://wilshire.imgur.com/oil#85a0f

I'm guessing that you can't see through a half inch of it. Also, you can't tell from the pictures, but there seem to be tiny little metallic specs in it if you shine on it with a flashlight. Am I being crazy?

Update: Compression test shows 150 psi across all 4.

 

That's awfully dark for 200 miles, but if it has water in it it might be a very slight amount. let it sit overnight and if it has water in it it will settle to the bottom. Where in Eastern PA?

 

Chester County. It's actually around 250 miles, 250 miles of heavy 202/Philadelphia traffic. A lot of stop and go. The engine is 190k miles old and likely has some blowby. So it could just be that dark normally. But if my gear oil looked like this, I'd be pretty sure there was some water in it. I'm just not sure how it looks for engine oil. The thing was definitely making more of a racket than usual today though. That part I am not imagining.

 

Update: Just did a compression test. 150 psi across all 4.

 

Your oil looks pretty dark for 250 miles, but if it had a significant amount of coolant in it, it would look like a chocolate milkshake. How does your coolant and radiator look?

 

My 86, with 200k+ miles on it, would turn fresh clean oil into exactly what's in your photo after one tank of gas. Not saying it isn't indicating an issue, though. A tune up is always good. Make sure you aren't getting gas in your oil, spark is good, all that.

 

rattling? my truck was doing that for a few days. now theres a rod sticking out my block, oh yeah and the motor only had 4000 miles on it. go get some 20w-50 oil. it could be a bearing.

 

I had a 94 that would ping when you got on it hard. Try a tank of high test gas. That should clear it up. If its only doing it when your on the throttle hard id say that's the problem

 

Your oil is dark, but doesn't look like it is mixed with anything. I agree with the quote, if you had anything mixed, you would know it because it will almost get foamy (milkshake-like) and the 2 liquids would be trying to separate on your plate. Instead of being able to see through to the paper underneath, you would lose the transparency because of the mixture.
I don't know what else to tell you about the noise, but after losing 2 head gaskets on an old Chevy (one recently), I can tell you it doesn't look like coolant/oil mixed is your problem.

BTW, that is a pretty good use for the income tax paperwork...

edit: Looking at the pics again, the last pic is questionable... Did you happen to notice any other things out of sorts when you noticed the noise? I.e. Did the temp rise? Truck start running different? Loss of power? Has the engine been opened up before? Recently?
Hard to tell because of the focus on the picture, but might be worth investigating further.

 

You can always got get an oil analysis done to see. Sure beats tearing the motor apart and not findin anything haha. How loud is the noise?