Fluctuating temp gauge

[floporama]

Have read up on some other similar problems, but thought i would run this by and see if anyone has any helpful tips.

My '93 XL 4WD never used to fluctuate on the temp gauge. About 2 months ago it started to go from about the low end of "O" on the gauge to between "MA" and back again over a 30 second period. Had the stat replaced, still did the same. Took it to Ford, said all electrical signals seemed ok, just getting low flow pressure. they rodded out the radiator, and now it cycles like before for a while and then evens out right at "RM" on the gauge. But then sometimes it never evens out, just fluctuates the whole time. If I run A/C, it runs hot, toward the right end of the gauge, unless i'm on the freeway, then it has no effect.

Also, the other day, took it up in the mountains here, and went uphill for 15 minutes straight at about 15 mph. by the time i got to the summit, the gauge had climbed all the way to top, and i could hear boiling when we got out. afterward, the problem seemed slightly worse with the fluctuation, just took longer to stabalize if at all. Any suggestions. The Ford dealer seemed kinda stumped too, so any help is appreciated. Sorry this was so long, just wanted to give all details cause I need any help i can get
Thanks

 

[mdrut]

Replace the hoses, bottom one could be colapsing, also could be the clutch fan..After seversl years, they tend to get weak and "FREE" spin, the result is not enough air being pulled thru the radiator..

 

[TPLYNCH]

You may want to replace the radiator cap if you haven't already. They get weak over time and are unable to hold pressure properly, causing the fluctuation in the gauge and possibly your boilover.

 

[Dbirl528]

I was having the same problem you are having. So I decided to replace the fan clutch, after flushing and filling the radiator and replacing the radiator cap didn't work. This was definitely the problem. After replacing the fan clutch, the temp gauge won't even go above the "O". I would really recommend you replace yours, as I would be willing to bet this is your problem as well.

 

[RON COX]

The problem happened to me after I changed the t-stat. A Ford tech. told me this was normal, it is not. I spent almost a year chasing the problem. I replaced everything over a period of time. It still was doing it. I noticed the wire to the temp. sending unit was corroded so I replaced the connector. Since then I've had no problems.

 

[takao]

I'm having the same problems, and was wondering if anyone had installed a flex fan with any good results and if so where they had purchased the spacer and the size of the fan installed.