DANCING TEMP GAUGE

[RON COX]

AFTER REPLACING THE WATER PUMP AND THERMOSTATE AT 130,000 MILES MY TEMP GAUGE DECEIDES TO FLUCTUATE FROM THE "N" ON NORMAL TO THE "M". PREVIOUSLY THE TEMP MAINTAINED A VIGIL AT THE "N". I HAD THE RAD. CORED, AND I REPLACED THE TEMP SENDING UNIT AND THE EEC-IV SENDING UNIT. NOTHING CHANGED. I INSTALLED A STEWART-WARNER GAUGE INDEPENDANTLY FROM THE SYSTEM AND GOT THE SAME RESULT. THE DEALER RAN A SYSTEM CHECK AND ACCORDING TO THEM NOTHING IS WRONG AND THIS IS NORMAL FOR 91'S. I'M NOT THE MOST KNOWLEDGEABLE SHADE TREE MECHANIC, BUT THAT IS A LINE OF B.S. ANYONE HAVE AN IDEA?

 

[Ray Lobato]

Hi Ron,
What was the temp rating of the thermostat that you put in? Dead Link Removed

P.S. typing in Capitol letters means you are YELLING. Just thought you would like to know. Dead Link Removed

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Happy Wheelin'
Ray L.
95 XLT 4X4

 

[Kampy]

Ron, sounds like you picked up a defective thermostat. I would put another one in it and try it again. I would suggest using a name brand part like NAPA, stant or an OEM item, I dont know whats available where you live. I had the same problem with a cummins diesel in a dodge this winter and another thermostat fixed it. Good luck
PS. They fed you a line of B.S.
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Kampy

[This message has been edited by Kampy (edited 04-28-99).]

 

[RON COX]

Thanks for the info., at the time I was yelling, I'm sure you can understand the frustration. The first themostate was a 190 degree from Carquest. I thought the same and bought a second, which I tested in boiling water before installing. No differance in preformance. I'm baffled. The thought of a cracked head is not appealing, but I have not seen any indications of that. Currently I'm looking into the pick-up sensor for the timing. Maybe something is shorting out. By the way, I'm in Las Vegas, Nevada.

 

[Ray Lobato]

Ron,
Did you have the Radiator cored before or after you started having the temp problem.
Sounds like the only thing you did before you started having temp guage fluctuation was change the water pump and the theromstat.
With that in mind, It seems to me that it would be one of the things you changed. Since you changed the thermostat and that didn't do it, then it must be the water pump.
Does this sound logical? Maybe the water pump is not quite pumping as well as it should. Question. Did the impeller look the same as the one you took off?
How about the fan belt is the tension OK?
Sorry just grabbing at straws.
When you find out what it is, Please let us know.

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Happy Wheelin'
Ray L.
95 XLT 4X4

 

[Longs]

Assuming that you don't have a problem with the radiator, thermostat, or water pump, my guess on the dancing gauge is that you have air in your cooling system. I just changed my water pump and had similar symptoms. When the temp sensor hits air, the temp goes up, then when it re-immerses in coolant, the temperature returns to normal.

I noticed that it takes several attempts to get the cooling system full of coolant after changing the water pump. The manual says the Explorer takes 8.6 quarts to refill, but I'd say it took 10-12 after having top and bottom radiator hoses and heater hoses disconnected.

The manual I had talked about "bleeding the cooling system" after changing the pump, but there's no specific way to bleed it. I had the temp gauge up past the "M" and didn't have any heat coming from the heater, which clearly indicated that the heater core was full of air. My solution was to park the Explorer facing uphill on a steep hill as my best attempt to "bleed" air from the system. I figured that if the radiator opening was the highest point in the cooling system, the air would have to bleed out. That appears to have worked, and my gauge is pegged right on the "N" to the "O", which is where I expect it to be.



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"Whoever said you can't fool all of the people all of the time, was a damn fool" Vince McMahon, 1999

 

[RON COX]

Godd call Longs. I guess the heater is the culprit. The service manual recommends that you run the truck at 2000 rpm with the rad. cap turned back to the first notch for approx. 2-3 min. after repeating this process twice the truck ran normal. I've never ran across that in any other vehicles. Thanks to all.

 

[NateEB]

Hey Ron
Did you ever get resolution on this?

 

[NateEB]

Hey Ron
Did you ever get resolution on this? I just replaced my thermostat and instead of just barely staying above the C and the first line on the guage. It floats up to the R or M and then floats back down and the heater still doesn't put out any good heat, its a little warmer but it still isn't hot at all. I have a 91 Taurus that will have you sweating in the dead of winter if you let the heater blow too much, I would like to see something similar with the X...especially since it's my wifes car and she doesn't like the cold. Let me know what you found.

Nate

 

[TPLYNCH]

Is your radiator cap still the original?? If so, replace it and you will probably lose the floating temp problem.

 

[NateEB]

I did that just about 5 minutes ago and am back at work so i can't tell if it will change anything. Hopefully it fixes the guage and i still have to bleed to fluid so that may help with the heat problem. I should know by tomorrow.

Thanks

 

[Iggy flywheel]

Might check the temp sending unit and the wire that connects to it. I put some dieletric grease on the connection to the sending unit. I could jiggle the wire and it would bounce around. It helps but think I have to replace therm again maybe get the jet brand.

 

[RON COX]

Wow that was my first post here! I found the wire connector to the temp sender had a short also. Once I did that everything was fine. But not long after all that the rad. started leaking from the cap and I ended up getting a new one. No problems since then.

 

[NateEB]

I have replaced the cap now. It is funny that the temp guage is floating up and down now...which it didn't do at all before switching the thermostat. When i am driving down the road it normally stays well below the N on the gauge and then when i am sitting just idling it will actuall move up to where it is supposed to be around the R and M on the guage...then goes down again when i start driving...any ideas?

Nate

 

[TPLYNCH]

Just a shot in the dark... Could be the fan clutch is keeping the fan engaged full time... Other than that, replacement Thermo may be faulty....

 

[Luv2explorer]

Hey NateEB---- Ever find your problem on the swinging temp gauge? I replaced my thermostat becausethe temp gauge would barely go past cold, and I would get next to no heat. Now the temp gauge fluctuates BIG time between cold and normal, and heat is still quite minimal --NEED HELP!

 

[Bigred08046]

There is a little ball bearing on the t-stat...that must be at 12:00 also have seen post to bleed system with an actual bleeder screw on radiator?? Has anyone seen this?

 

[olemech]

try cutting the center of the thermostat, or put a 180 degree . this will affect gas milage,i have 1996 4.0 with the center cut out and haven't had any problems.