I have a question my bothering law has a 2005 explorer where the thermostat seems to be opening too late and pushes coolant out of the explosion tank. We have replace the thermostat three times with a new one and the same thing is still happening from a cold start. The thermostat opening temp is 88c/192f I am wandering if anyone has had this problem with their Explorers.

 

What temperature thermostat are you installing? I don't think that a thermostat opening at 192F would explain coolant being pushed out of the recovery tank, sounds like there is another issue happening, such as poor flow of coolant through the radiator, poor flow of air through the condensor and radiator, or a fan clutch or electric cooling fan that is not working properly.

You don't mention any concerns with how it runs or drives so a head gasket may not be a concern, but if you are convinced that the radiator/fan/air flow is not an issue, a check for combustion gases in the cooling system may be in order.

-Rod

 

Once the thermostat has opened the car drive normally with no problems at all. Dose not push coolant out of the expansion tank. And you never think anything was wrong.

 

Hopefully the thermostat is installed with the proper side to the engine. Know of a couple of times owners had installed them upside down and had issues like you are having.....worth the thought.

 

does the temp gauge spike to full red, then drop back to mid range all in a span of 10 seconds ? Or the gauge is normal, just thermostat problem ?

 

Yes it dose go to the red and then drops back too normal. But by that time it has pushed coolant out of the expansion tank. And you get an over heat warning on the dash display plus a chime warning.

 

That sounds a bit like air in the cooling system, although I wouldn't expect air to cause coolant to bubble out of the overflow tank unless the tank is REALLY full or there a whole lot of trapped air.

-Rod

 

I had that on my old F150....... My opinion was I had a small hole in the head gasket. Overnight the cylinder that was on compression would push flue gas thru the hole and buildup an air (gas) pocket at the top if the motor, by the temp gauge sensor. When you startup in the morning, the thermostat is closed and the coolant is suppose to circulate in the motor as it warms up... but not go to the radiator. As it warms up, the air pocket expands and also the temp gauge is not in the coolant. About the time the thermostat opens, the gauge spikes to red hot, the air bubble goes into the radiator, and a good BELCH is formed in the radiator / overflow tank. ......... I had all of that.. Pin hole is small enough that you don't loos MUCH water and don't get MUCH gas into the coolant while running ........ but EVERY MORNING you get the belch. I ended up putting some BARS COPPER gasket and head sealer into the radiator top hose and running the motor as normal to work, etc.. Each night I was hoping the sealer would work down into the head gasket hole and eventually seal it......... couple days later I had it sealed up......... worked for about 8-10 months, then I had to do it again .. Only long term fix is replace gasket.

 

https://www.ford-trucks.com/forums/8...lant-blow.html

 

Interesting, another one to save to the memory banks.

-Rod

 

There are several items around the intake manifold that will cause this if you are having to add water with these systems lookout. There is three main items to look out for the intake gasket, bolts too long in the manifold and the intake manifold. Had all three found them one at a time.

 

What brand of thermostat? I have had bad luck lately with anything other than Ford thermostats.

 

I have been using the Autozone 180 Degree thermostat with good luck. Don't think it will do much in your case.