Overheating and puffing up like a balloon.

[91EclipseGSX]

It is a 91 GSX to start. Basically it overheats to redline within 5-6 min even at idle. The upper radiator hose starts to expand like a balloon while the lower hose does not. I assume its blockage somewhere. Which way does the coolant flow? I dont have access to my car to answer this myself. If you have even seen this please let me know. My car is in storage two hours away so I am trying to get some ideas before I make the drive. Any and all help is appreciated.

[Jusmx141]

Either your rad is clogged, the thermostat isn't opening, or the water pump impellers have rotted off. If the top hose is rock-solid and the lower hose is cool and soft, you're not moving water and it could be any of the three issues described in the previous sentence. An OEM pump uses a stainless impeller, so if you're using an OEM pump you likely have nothing to worry about with the actual pump.

The coolant flows top to bottom- the water pump draws from the lower hose, moves coolant through the block and out of the head into the thermostat housing. After the thermostat has regulated the temperature, it will open and allow the hot water back into the top of the rad where the cycle repeats.

Rule of thumb is that rads generally flow top to bottom being that hot water rises by nature.

Another possible issue- and I hate to say it...could be the head gasket allowing cylinder pressure to seep into the cooling system.

[gdmbat85]

Your radiator is either clogged, or you have a deteriorating hose. If the hose is deteriorating, that doesn't explain the overheating, but if the radiator is clogged, that'll explain both. My money's on the radiator.

[91EclipseGSX]

Thanks for the info. I will start with the easiest of these areas and pull out the thermostat and run it. If still overheats and puffs up Ill pull the radiator and check the flow. I have never changed the waterpump from OEM. If it comes down to the head gasket, I will just have to do it.