Cadillac Repair: Overheating 4.1, head gasket leak, radiator cap

Question
I have a 83 Eldorado with a 4100 that over heats after being driven for about 15-20 miles. It has a new water pump, radiator, rad cap and thermostat.  Shortly after warming up I stop getting heat in the cabin. I have tryed many times to get any bubbles that may be in the block out but have had no sucess in finding any. I recently saw that napa lists separate water pumps that rotate clockwise or counterclockwise. Are ther two different pumps and could this be my problem? Any help would be greatly appreciated.
                    Tris  

Answer
ABSOLUTELY this has been known to happen. Also I have seen many times where the serpentine belt was installed incorrectly thus causing the water pump to spin in the WRONG direction.

4.1 engines are well known for having faulty head gaskets that put combustion chamber pressure into the cooling system.

1. remove the spark plugs.

2. remove the radiator cap and make sure the radiator is FULL of coolant.

3. Using a compression gage hose, remove the check valve from the bottom of the hose and thread the hose into each spark plug hose and attach 80 lbs of continous air pressure to the hose and watch for bubbles in the radiator. Do this with ALL 8 cylinders and if you see any bubbles in the radiator, you have a head gasket leak.


autohelp