Bronco II Overheating

[The Fonz]

My Bronco II started to overheat last night after I noticed the smell of coolant. In the last few weeks I have been towing the boat (a 1448 tracker) and I had my a/c system totally rebuilt. I did not let the gauge go past the bottom of the "N" but it started to climb rather quickly so I have no doubt it would have gotten there. I am really hoping it isn't a blown head gasket or worse, I placed my hand over where the radiator cap usually sits and noticed there wasn't any suction.

Additional Details:
The fluid came bubbling out of the cap when I got home, so much so that the coolant level was extremely low afterwards.

Any ideas? It's hard to test if it is just a thermostat because the heater will blow hot regardless of the internal temperatures today.

 

[PetesPonies]

Obviously the most common would be a thermostat that went bad. You just need to change it to be sure. If it isn't really overheating, it may just be a faulty cap. That can be checked with a pressure gauge.

 

[RonD]

With engine cold, remove rad cap and overflow hose
remove coil wire, we want a no start

Put a latex glove over the rad cap opening and seal it with a rubber band, block the overflow hose outlet, vacuum cap or short hose with bolt in the end works
Cooling system should now be sealed.

Turn over engine and watch glove, it will start to inflate it you have a blown head gasket or cracked head.
Piston compression pressure, 150+psi, is being forced into the cooling system.

Rad caps hold 16psi of pressure so a leaking head gasket, 600psi when firing, will force it open blowing more than the normal amount of coolant into the overflow tank, so you get the smell of coolant, and tank would continue to bubble after engine is off until cooling system pressure got below 16psi.

But it could just be a bad rad cap or t-stat, or even a leaking hose, once coolant level drops enough you have a cycle of overheating, any air in the system restarts that cycle.