1996 ford explorer with fluctuating temp gauge

[stafphoto]

Ok so I have a 1996 ford explorer with the 4.0 v6 in it and I am having a problem with the temperature gauge fluctuating up and down along with the heat in the truck changing temp warming and cooling. I have replaced the thermostat, the coolant temperature sensor and the sensor that sends the signal to the gauge itself.

So my question is what else could be causing this both the gauge fluctuations and the heater temp changes? And ideas would be great.

 

[deweyville65]

Ok so I have a 1996 ford explorer with the 4.0 v6 in it and I am having a problem with the temperature gauge fluctuating up and down along with the heat in the truck changing temp warming and cooling. I have replaced the thermostat, the coolant temperature sensor and the sensor that sends the signal to the gauge itself.

So my question is what else could be causing this both the gauge fluctuations and the heater temp changes? And ideas would be great.

my 96 temp gauge fluctuates all the time. But I do not notice any variation in the heat output. My heater puts out 150-160 degrees at the center vents. Plenty warm, and stays constant unless I regulate the temp setting. First question is, Is the radiator, not the reservoir, full? Are, or how much, coolant are you loosing? answer this, then go from theere.

 

[cthudak]

Had the same problem about 5 years ago in my 97 Ranger...Changed everything you did......turned out to be radiator...Took it to a local radiator shop, and they flow tested it.....had restricted flow....changed it out, no problems since

 

[stafphoto]

I've been doing a little investigating and found this:

Ford Explorer 4.0 V6 1994 - 1996

Problem: Knocking noises from the cooling system and the coolant temperature gauge fluctuating.

Solution: The cause may be irregular flow of coolant moving through the cooling system. The solution is- Explorer 1994, A new revised water pump and gasket should be fitted. Explorer 1995 - 1996, A by-pass kit should be fitted. The kit consists of a distribution element, reducer element and modified coolant hose.

And this:

FORD:
1995-2000 EXPLORER, RANGER

This TSB article is being republished in its entirety to include 2000 model year vehicles and to provide Service Part(s) and Labor Time information.
ISSUE
A temperature gauge fluctuation and/or a "knocking/thumping" noise may be audible in the passenger compartment on some vehicles. This noise is most pronounced with the engine at normal operating temperature. The noise is caused by steam formation in the cooling system. The noise is then transmitted through the heater hoses and heater core.

ACTION
Install a Coolant By-Pass Kit. This increases coolant flow which reduces steam formation. Refer to the following Diagnostic and Service Procedure for details.

DIAGNOSTIC AND SERVICE PROCEDURE
1. Check for excessive exhaust system restrictions. A restricted exhaust could elevate cooling system temperatures.

2. If dash-mounted cooling temperature gauge fluctuates, check that gauge and sending unit are functioning properly.

3. Check for restrictions or kinks in the radiator or heater hoses.

4. Pressure check cooling system for leaks.

5. Confirm proper Engine Coolant Temperature (ECT) sensor signal to EEC-V processor.

6. Check for correct 50/50 coolant mix. Verify that freezing point is -37°C (+/- 15°C) or -35°F (+/- 5°F).
edit:
7. If concern still exists, install service Coolant By-Pass Kit and verify that concern has been resolved. Refer to the Application Chart in this article.

PART NUMBER PART NAME

F8PZ-8522-AA Coolant By-Pass kit
F8PZ-8522-BA Coolant By-Pass Kit
F8PZ-8522-CA Coolant By-Pass Kit



I have both the gauge problem and an unknown knocking/thumping noise and am now curious if the above things may be my problem.

 

[deweyville65]

I don't know about yours, but mine is just the thermostat cycling. I have grown to ignore it. It causes NO problems

 

[Jstcruz]

I read on here that a messed up rad cap will cause gauge fluctuation, but I did not see that it would cause the temp at the vents to change. but still, you may want to check on that

 

[stafphoto]

I messed with burping the system for a bit today and the heat seems to be working ok now. I'll pick up another radiator cap tomorrow after work since they are cheap. If that doesn't fix the gauge movement then I guess it's going to stay that way. I'm planning on having the engine either rebuilt or swapped for another one in about a month anyways (I have a possible timing belt slap) so I am not into spending a bunch of money or time messing with it. As long as the heat keeps working until then so I don't freeze it's fine.

 

[deweyville65]

"Timing belt slap" on a 96? 96's did not come with the OHC engine. Please explain what you are refering to, as I what to know what to look out for on my 96. 4.0 OHV engine. Namely what else can go wrong.

 

[stafphoto]

Well I had a little talk with a mechanic recently and found out what's going on with the explorer, my intake has gone bad. The ticking noise is not the timing belt but the lifters. I have an oil leak only well driving do to seeping out of the gasket. It's also the gasket being bad that's causing the gauge to move do to air being sucked into the motor and getting into the cooling system.

So yeah for me I am going to be getting the top end of the motor rebuilt within the next two weeks.

 

[injunbilly1]

I think I have the same things going on with mine. "the temperature gauge fluctuating up and down along with the heat in the truck changing temp warming and cooling.

I already changed out the temperature sending unit and I've have two people say that the problem is probably in the dash. But I also have oil leaks that is dripping on my exhaust.

 

[abikerider]

I had this same problem and, after dealing with this off and on for years, I noticed that it doesn't happen when on max air conditioning or if the heater selector is off. Both these settings cause the vacuum-operated heater bypass valve to bypass the heater core. It seems that there is not enough flow through the heater core and this is causing a hot spot in the engine and creating steam pockets.

My solution was to create a permanent bypass on the heater core using reducer tees on the heater hoses with some 3/8" hose used for the bypass. After I installed it the symptoms went away and stayed away and I still get plenty of heat from my heater. I suggest seeing if the symptoms stop when the heater selector is in the Off or Max Air Conditioning setting. If so, my solution should help. I hope this helps if anyone comes back to this thread.