Temp Gauge Problem or something else?

[xTOM153x]

Over the past month my temperature gauge has been going up all the way up to Hot and then after about 10-15 sec goes back to normal(middle) it does it randomly and just wondering if its something to worry about

 

[Equnoxe]

i would replace the thermostat if it has not been done, i also believe i saw a thread on here that there was a fix for this (assuming its not the thermostat) cannot remember the thread tho, anyone else remember? its a big thing to worry about, overheating you motor, very often means your motor is now garbage

 

[Vargas]

Random fluctuations are either a bad temp sensor, or air pockets in the cooling system.

 

[DLinkOZ]

Mine did the same when the thermostat stuck closed. Would just get to hot and then suddenly back to normal. It actually came out in two pieces. Very easy fix, should only take 10 minutes and I think just a single size socket for 3 bolts. Less than 10 bucks as well.

*EDIT*
I should add that you should do it NOW, don't wait. You're building up pressure, and it's going to release somewhere. I lost a fair bit of coolant, luckily it wasn't into the heads (which is a very real possibility if you let it go). Mine seems to have loosened the seal on one of the plastic end tanks and I now have a very slight leak. So that $10 part turned into a new radiator.

 

[Vargas]

Mine did the same when the thermostat stuck closed. Would just get to hot and then suddenly back to normal. It actually came out in two pieces. Very easy fix, should only take 10 minutes and I think just a single size socket for 3 bolts. Less than 10 bucks as well.

*EDIT*
I should add that you should do it NOW, don't wait. You're building up pressure, and it's going to release somewhere. I lost a fair bit of coolant, luckily it wasn't into the heads (which is a very real possibility if you let it go). Mine seems to have loosened the seal on one of the plastic end tanks and I now have a very slight leak. So that $10 part turned into a new radiator.

If your cooling system pressure was high enough to cause the radiator seam to leak, then either the radiator was flawed or your radiator cap was defective. All parts of the cooling system should withstand pressure beyond what a properly functioning cap will allow.

 

[DLinkOZ]

The radiator/mount on the Explorers is indeed flawed. They'll leak on their own (as evidenced by the threads on this site alone), much less with any additional pressure. I'm sure my inicident hastened that inevitability.