Got a 97 Ford Ranger 4 cylinder last year. Noticed that the coolant looked funny when I got it, but only got around to flushing it this year. It looked like there "might" be oil in it. It was very brown, but the oil wasn't floating on top like I would have expected. Does the coolant cause the oil to mix in real well, or is this just some really funky coolant?
Is there a common problem with this version of the 4 cylinder to cause the head to crack or the gasket to go?
Change and flush your coolant system.
Then check it again it maybe dirt or rust in there.
If it is milky than you have a cracked head or gasket.
Definitely not milky. I did flush my system about four times, and it slowly got better (of course there is the fluid in the engine itself that doesn't drain out, so it took a number of cycles to get it even somewhat clean).
I am leaning toward rust/dirt, as it didn't look anything like a water and oil mix that I have seen, but I thought that maybe the coolant allowed the oil to mix more normally. I might just mix up some coolant and water tonight and see what it looks like to convince myself that wasn't it.
The coolant basically had the same consistency of normal coolant, but was dark brown rather than green.