Temperature gauge rising from 1/2 way point

[JExplorer98]

Is it the fan clutch or the belt that causes the temperature gauge rise and fall from half-way point on the temperature gauge. Engine reaches the normal half-way while driving under normal conitions and then rises to hot and falls down again to the half-way point. Fluctuates. Started doing this on 9/16/3, never happened before to my knowledge. Had the truck for 9 mnths. 98 Explorer XLT 4.0 SOHC. 58000 miles. Enough anti-freeze. Not sure if anything is clogged. Engine sounds fine when accelerating or at idle. Any ideas will help!

 

[RickOTR]

Have you checked the thermostat. I replace mine after each flush like clock work every 25,000 miles, and it runs like new.

 

[JExplorer98]

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I'm not sure when the therm. was replaced. I bought the truck December of 2002. This just started today. It could be that the therm. is sticking, not properly working. Not sure. Have you had this situation yet?

 

[Alec]

First thing to do would be a coolant flush with new tstat and rad. cap. Needs to be done anyway as part of regular maintenance. If you still have problems after that it could be the fan system or water pump.

 

[RickOTR]

I agree with Alec and flush the coolant, change the therm, and install a new radiator cap. Also try and clean the coolant sending unit(s). I have never had this kind of problem as I follow a very strict maintenance routine.

 

[JExplorer98]

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I've had a similar problem with my 91 Cougar and that car had 167,000 miles. The car still ran great with the high mileage. I was hoping to get the car past 200k but I sold it. I'll eventually fix the problem, just as long I don't spend a few hundred dollars on fixing it.

 

[RickOTR]

Coolant Flush.. $40
Thermostat... $18
Cap... $4

Worth every penny....
By the way, I just changed all the radiator hoses and was glad I did. The hoses had a lot of rot in them, and I only have 97,000 miles on it, and change it every 25,000 miles.