1996 Civic EX auto, 170k mi. It is loosing coolant but leaking. It will consume roughly 16oz water on a 30 mi. drive. Temp gauge is usually ok until I come to stop for an extended period of time, then the temp needle with pretty much max out, the cooling fan will come on when the needle hits the top but doesn't do a whole lot for the cooling. I don't drive far enough for the water/coolant to be completely empty (otherwise I think it eventually would).

I bought the car two years ago after the radiator blew and cracked on the previous owner, since then I put a new radiator, water pump (twice), cooling fan switch, coolant temp sensor and thermostat.

My radiator cap does have a light coating of light brown oily-looking substance on it, there is no water/coolant in the oil...

What test will tell me if it is a cracked block or cracked head?

Thanks ya'll

 

I also replaced the head gasket about 6 months ago, checked it with a level and feeler gauges for warpage, didn't find any obvious warpage.

 

From the description, the head is slightly warped and the Head gasket blew causing the symptoms you are seeing. Either way, you're taking the motor apart.

 

No worries, the first time was easy, the second time will be a piece of cake...