Cadillac Repair: Coolant blockage Overheating, olds aurora, radiator hose

Question
I have a 97 sts 4.6. It seems the coolant is getting held up somewhere on the intake side of the coolant flow. When I start the car and warm up im all set. pull car out on street and accelerate and all fluid is blown out of overflow tank hose. Someone mentioned a clogged radiator, I installed a new radiator and thermostat. Cant be waterpump because it is building enough pressure to blow fluid out.I just blown a incoming radiator hose from the thermostat side most likely because of fluid blockage. If I have the heat on it tends to hold on the fluid for a longer time than if no heat if running. But still same case scenario fluid gone car overheats. P.S can you get me a coolant flow diagram on a 4.6 so I have a better idea where the coolant flows for future diagnose. Any help would be appreciated

Thanks Kevin

Answer
Hi Kevin,

       From what you describe this sure sounds like a head gasket or cracked head issue. I hope I'm wrong but the Northstar engines have developed a history of stripping the head bolt threads in the block and then that is what causes the overheating to occur. Napa or bigger auto parts stores have a block tester kit which is a liquid that is placed in a tube and then steam is drawn into the tube with a bulb while the engine is running or by the exhaust gasses being forced into the tube through the radiator filler neck opening. If you have a leak the liquid turns from blue to yellow.

      I'm not able to send illustrations by this site but if you subscribe to alldata.com you will have all the info you need as well as service bulletins to help you out with this problem.

       One suggestion would be to go to your local public library and they will have shop manuals and might even have a Caddy manual '94 on up or an Olds Aurora that will give you the diagram you seek. Otherwise the flow of coolant goes like this: coolant heats up in the engine, flows through an open thermostat, upper rad hose, top of the radiator, exits lower rad hose into the engine block, pushed by the water pump into the head and the cycle repeats.

      Hopefully I have been of some help. Bill