I got a 94 Ranger with the 4.0 in it. It just rolled over to 178,000 miles and i am having a major coolant loss. I just used up a gallon of coolant in 2 days and im really stumped the reason why im lost on this is because its leaking outside the truck. I checked all the rad hoses and they are fine no leaks, i check the water pump and its dry as a bone. I watch it drip out onto the ground and it looks like its coming from the back of the motor so i know its not the radiator. Could my cylinder head be cracked where the water jacket is it and maybe its leaking from there? Im so lost and buying a gallon of coolant every 2 days is getting expensive.

 

Possibilities:
heater core or heater hoses or bypass valve (if equipped)
freeze plug
lower intake manifold
heads/head gaskets

I would go to autozone and put down the deposit to borrow their cooling system pressure testing kit (I had this out a week ago for a radiator leak). Then you can pressurize the system cold and get behind the engine and figure out where it's leaking.

 

Pull a few spark plugs and read them. If I remember correctly, if they look "steam cleaned", then you need to stop driving the truck for sure as you have some intake mani leak.

 

Well i did a pressure test and it held the pressure pretty well, all the hoses were stiff. That same day it did not leak but the day after sure enough i had coolant on the ground.