Leak from rear of engine

[vacaville dave]

I just bought a 91 eddie bauer explorer. I noticed a small puddle under the engine, to the rear, and I thought it was oil. After crawling under trying to find the source, now I'm not sure if it's oil or coolant. I actually think its a mix of oil and water. I could not see the source, but it's dripping down from above the starter on the driver's side, and above the oil filter on the passenger side. I checked the coolant level, and it was a little low. The oil level is fine, and looks good. Unfortunately, I haven't had it long enough to know if the prior owner didn't just change the coolant and the oil to cover something up. Any ideas?

 

[ChasAld]

Some of the 4.0L ford engines are noted for developing leaks around the core (freeze) plugs, especially on the back end of the heads, against the firewall, especially a high mileage engine. Not easy to see and hard to find when the engine is cooled down and the cooling system is not pressured up. If you can pressure the system to about 15lb., when everything is cooled down, and search for the leak it will be easier to find if in fact it is a coolant leak.

Charles