truck overheating only for 10 or 15 seconds?

Question

Ok so first thing in the morning when i drive my truck(2002 ford ranger) the temp gage goes to max and the check gage light comes on. This happens like 5 minutes after i leave the driveway. It only stays there for like 10 seconds the drops back down to normal quickly. I think maybe the thermostat is sticking. What do you think. It does not happen at all the rest of my drive.

Answer 1

Thermostat sticking. Could be caused by age. Not keeping antifreeze/water at proper mix causing system to oxidize a little (rust)
Change thermostat. I recommend that thermostats be changed at least every two years as preventive maintenance when you change your hoses and belts.
AND GET A MOTOCRAFT THERMOSTAT NOT A CHEAP SUBSTANDARD AFTER MARKET THERMOSTAT!

Learned that the hard way. being out on the road in the middle of the night with a stuck thermostat changing it used a flash light.

After you change the thermostat be sure to purge the system to get all the air out of it.

Answer 2

You can try a thermostat first. DO NOT DRILL A HOLE IN IT! Repair tactics from the 60's and 70's do not apply to todays cars. Make sure the system is full after you are done replacing the stat. You could have a bad coolant temp sensor or guage too.

Answer 3

Either the thermostat is sticking, or there's an air pocket getting trapped under it causing it to stick. Put a new thermostat in, and drill a tiny hole through the body part (not the valve) where the coolant passes, it will allow the air pocket to pass without letting too much coolant by.

Answer 4

Either thermostat, or an air bubble in your coolant. Have you re-filled your coolant recently, or taken the cap off the radiaor? Is there a leak anywhere? You need to be careful with it overheating because you can melt your head gasket.

Answer 5

I would swap the thermostat first, as it is a cheap fix. If that doesn't work, you may have a bad sending unit, or a short in the wiring between the sending unit and the gauge.