Driving in the highway to the city this morning for my 7am hockey game and all is well. Truck running fine; lots of heat in the cab. It is about a 12 mile highway run and another 4 miles in the city to the hockey rink. As I said all was well... exited the highway and stoped at the first traffic light. Noticed the tempurature needle was almost to the HOT end of the "Normal" bad on the gauge... that is not good. Then the needle dropped quickly to the mid-point where it normally resides. Stayed there for the rest of the day and the trip home.

Is it possible the thermostat was stuck and only openned when I stopped at the traffic light? Sure acted like it.

 

I don't think it would be your thermostat. It would open before 12 miles of driving. I would keep an eye on it. Could maybe be a fan clutch starting to go? Just watch your temp gauge more often and report back.

-Matt

 

Have you ever:

1) hooked a mechanical gauge up to the truck?
2) changed your thermostat,
3) taken your radiator off and had it flushed by a radiator shop, or
4) checked your fan clutch?

If you answered no to question #1, that would be the first thing I would do. Ford gauges tend to jump out and down for no reason.

If you answered no to all of those questions, I would do everything on the list, one step at a time. If you do the work yourself, the most you'll spend would be $100.

 

Had the radiator replaced last summer. New fluid that still looks good. Thermostat was replaced about 3 years ago when I replaced the water pump. Have never checked the fan clutch or used the mechanical gauge.

 

Thanks Matt... could be the clutch... never thought about that. Radiator & fluid was replaced last summer... water pump and thermostat replace 3 years ago. I will keep watch. That was the first time I noticed it.

 

Since you have replaced the radiator, and thermostat recently, the fan clutch is the next obvious culprit. If you don't know how old the clutch is, it is likely time to replace it, given the overtemp problem.

 

Well, if it was the fan clutch, wh would it run cooler in town than on the highway and why would the needle drop quickly like it does when the thermostat opens?

 

that is why I mentioned using a 'real' gauge. You might be running hotter on the highway b/c the gauge is getting more juice from the alternator. my truck would do that.

 

Unless you're idling in the McDonalds drive thru for 10 minutes, you should be able to drive around all day with no cooling fan. I have an electric fan on my 5.0 Bronco and never had to turn the fan on even on hot days as long as I was moving. (only time it was turned on was when slow trail riding or in the mud holes) Check the grounding straps to your engine, that sometimes makes the gauges do strange things. I also agree with an aftermarket mechanical gauge installation, get one that has a broad temp range and of good quality.
007BRONCO

 

its probably nothing to worry about the motor just gets hot then you come to a stop and there is very little air flow on your radiator. once you drive it cools down again

 

Just returned from a 200 mile round trip to my Dad's place for Thanksgiving dinner. Truck worked fine... tempature stayed right where it should be both on the highway and in town. I will keep an eye on it for the next few days.