Hi Folks,

I was after some tips to help remove air locks from my cooling system.

I recently had the rad repaired and reinstalled it with new hoses etc and now the temp gauge is show erratic high temperature. The needle seems to hover arounf the L of Normal and then quickly varies between the M and L.

I'm assuming its an air lock. The top hose etc is all hot and I have run the truck witht he cap off the rad to allow most of the air to escape.

The ford book says to disconnect the heater hose at the joint above the Alternator (done it) but I suspect there is air somewhere else.

Any suggestions.

Simon

 

yes you might have a air bubble trapped in the block or heater core, burping the system is the only way to get it out. Some will say that if you keep the overflow tank full it will burp its self. I'm old school on this, cold engine, remove the stat cap, get some rags, fire the engine. Now watch the level as it warms up it will drop then it will rise, wanting to over flow due to the air in the system expanding. when it rises a folded rag to protect your hands as the rising coolant will go to the catch tank. once you see where the thermostat has opened and you can see the flow thru the core, add some coolant. Now the stat will close, wait for it to open again and then add some more. Once you have heat, depending on your make & model, turn on the heat as some might have a valve that turns off the coolant flow to the heater core. Hint, the upper hose can hold some air, once the system is burped, you can take the upper hose and carefully (engine off) bend the hose moving the air towards the rad. If you got the air out you should see your gauge level out and not have as much movement. Some systems can be a bear to burp, My 2.9 in my bronco II has always been a major pain to burp.
***NOTE*** NEVER open the cap on a HOT engine, you can get burnt cause the coolant is under pressure and loweres the boiling point. And Never add water or coolant to a over heated engine IF the engine IS OFF. That can crack the block or heads. When adding to a hot engine make sure its running. Hope this helps, Keep Em' Twistin'! Bob B.

Bronco Stables: 89 thru 96 / XLT / Eddie B / BR II

 

chances are its an electric problem with either the sensor or the connection to the sensor. The coolant gauges dont react that fast to temp changes. My guess is electrical.

 

hmm didn't consider that but it does make sense. The sensors are pretty slow to react usually. I'll check the contacts on the Temp Sensor and maybe replace it.

Simon