Cadillac Repair: 1993 Cadillac Sedan Deville/overheats, coolant temperature sensor, bolt holes

Question
I purchased this car a year ago.  I immediately began having problems with it overheating to the point that the antifreeze in the overflow would actually boil.  It of course blew a head gasket. The lot I bought it from replaced both the engine and the radiator.  Had no problems until now. With the weather getting warmer the car has begun to overheat again (only not to the boiling point this time)  The light does not come on, though it does work when I check all my lights.  I replaced the radiator again in Feb.  It pings, loses compression and runs really rough.  I've replaced the thermostat, the radiator cap, 2 relays (under the dash) and the coolant temperature sensor.  Nothing has worked.  The warmer it gets the shorter the distance I can travel.  When checking to make sure the fans came on, I touched the radiator hose and it did not seem warm to me.  Please tell me this is not another blown headgasket and can you direct me into what I should look for next?  Thanks!

Answer
I know that you do NOT want to hear this, But this sounds exactly like a head gasket as these engines are very common to stretching out the head bolt threads in the aluminum engine block due to the steel head bolts.

Your going to have to replace the engine or fix this one by drilling out all the engine bolt holes and installing heli-coils in all the engine block head bolt holes and installing different head bolts in order to fix it.