My 96 pickup with inline 6 started a drip from the right front of the radiator (when looking at the grill). When I opened the radiator cap (very cold engine) the fluid gushed out!! How can it be under pressure? Thermostat stuck?

Please help.
Thanks,
Steve

 

Is the engine running hot ? Even if the thermostat was stuck on a cold engine the pressure will eventually equalize . How bad is the leak at the radiator ?

 

Now I'm starting to think the radiator was overfilled and the leak was from the overflow container. The radiator is still full!??! I started it and let it get warm, no problem. Drove it, stayed on low end of Normal range. Heater works fine too.

Could it have been overfilled?

 

The radiator will only hold so much , the rest goes to the recovery tank . There is a cold full mark on the recovery tank .

 

I understand that, but how did I loose some, but still have it appear full?

 

I noticed the same thing after I replaced my old leaky radiator. The old rad had a slight leak around the radiator pan gasket on the side of the upper radiator hose. When the engine was cold and I opened the rad cap nothing came out.

When I swapped out the rad for new one, and the engine was cold, fluid gushed out. I can only surmise that the pressure was always there, but the previous leak relieved it.

I didn't change out the rad cap, but I did replace the old 195 stat with a new 195. All new hoses too.

The engine isn't running hot, nor is it exhibiting any abnormal symptoms. I'm not worrying about it. Should I?