Cooling system issues

[hobie_01]

I have a 2006 Ford Explorer 4.0L SOHC v6. The temp will rise to Hot on the gauge and the idiot light comes on. Within a minute of these conditions, the idiot light will go off as the temp drops rapidly to the normal range. Is this a sign of a thermostat going bad or a bad temp sensor?

 

[Dag06XLT]

Sounds like air pocket, but thermostat and sensor are so easy to change and inexpensive worth a change if not already done recently.

 

[Flag Gibby]

If you have air in the system then there is a leak somewhere that needs to be taken care of before you cause some really expensive damage to the engine. I doubt that there is anything wrong with the temperature sensor since your statement indicates that it is functioning correctly and not stuck on cold or hot. It has been my experience that the sending units don't go bad but the o-ring on them does go bad and starts to leak.

 

[hobie_01]

I looked around on the forums and saw some threads about the thermostat housing problems. I looked at mine and saw some residue around the lower part of the housing. My coolant was low, so I'm guessing that it was leaking there. I bought the Dorman replacement kit. It came with everything, even a new sensor. I accidentally broke one of the alignment tabs while removing the old part. It took a while to fish it out, but I got it. I put the new one in and topped off the coolant. So far so good. Thanks for the replies.