brain bugger on 95 3.0 ohv

i own a 1995 ford taurus 3.0 ohv auto the brain bugger is that i replaced the engine and tranny last summer (07) and recently about 3 months ago my temp gauge spikes to hot when sitting and then drops to cold again and it also does it when i jump on the gas getting on the freeway........ i have replaced the following items 1. thermostat (twice) 2. thermo houseing (1) 3. temp senser (1) 4. temp sender unit (1) and last 5. temp gauge.......dont know what else to do check or fix other than take thermostat out completly any help would be great thank you

You need to make sure the cooling fan behind the radiator is working. Your symptoms are pretty classic for a fan that's not running, either due to the fan or due to the power supply to the fan.

-Rod

thats the thing i hear the fan kick on some times could the fan sensor be going out?

Does the overheating ever occur when the fan is running? Which occurs when you jump on the gas at a freeway exit, high temp or cooling?

The more information you can provide, the better.

-Rod

What often happens is that one fan is broken and the other works. Turn on the AC and see which fan comes on. That one should only turn on when the AC is running or if the temp goes very high. The other should cycle on and off to control temperature. What you described sounds like the fan that is not used for AC has a bad motor. You can unplug it and run a couple leads from your battery to it to test it (don't shock yourself).

Ok first off it just spikes when ever then drops just the gauge nothing else as for the AC that has nothing to do with it hence i only got one fan but thank you and it just spikes real quick and drops real quick nothing else happens it doesn't over heat just spikes to almost hot and then drops to cold or the normal temp that it is running and when or if i drop it out of gear to nutrual it drops right away its like the thermostat isn't open right but it is brand new i got a new lower hose and im gonna replace that now and see if that helps i have replaced everything else that i can think off if i am forgetting something to replace please let me know i use this car to drive maybe 20-50 miles a day and thats about it home-school mostly all back roads only freeway if i have to and as for the fan no it works and no over heating it does get warm faster than normal when i am sitting in traffic or the car is in park or in gear like the thermostat isn't working right or the hose is crimp (over preasure) and thank you guys for the help

See if you have air trapped in the cooling system. Since you've had the system open recently, there's a good chance there's air in there. Did you notice if the new thermostat had a little jiggle valve in the flange?

-Rod

i honestly dont remember if the thermostat did or not and how do i bleed this system out its nothing that i have worked with or remember how to bleed


P.S. Thanks Rod for the fast replys

Don't know if it's the same with the '95, but my '97 is a "self-bleeding" cooling system. The degas bottle is supposed to continuously burp any air out of the system. On my Chevy, however, I have to turn a small brass hex-head bolt near the thermostat to bleed out the air. As soon as liquid starts pouring out continuously, I (softly) close the hex-head bolt.

I don't have the answer to your problem but I will share my experience with a simular problem in hopes that you might get some useful information from it.
My sister-in-law has a 96 3.0 ohv and her temperature gauge would spike just as you described. Hers also would do it when the turn signals were used or the electric lock were pressed.
I checked for bad fuses, shorts, replaced the thermostat, hoses, fluid, etc... Unfortionately the problem remained. I kind of gave up as it seemed like a strange malfunction that wasn't affecting the actual temperature of the car.
It's been over a year and thousands of miles of L.A. traffic and there has been no problems other than an erratic acting gauge.

Good luck,

Taurus GLenn

The service manual does not specify (at least not that I've found) how to bleed the system, but it does state, "Fill and bleed engine cooling system with a 50/50 mixture of Ford Premium Cooling System Fluid E2FZ-19549-AA or B (in Canada CXC-8-B) or equivalent meeting Ford specification ESE-M97B44-A and water as outlined."

Additionally, it implies that the factory thermostat has a jiggle valve and that said valve needs to be in the Up position. That doesn't mean though that an aftermarket thermostat would have the valve. With the valve though, the system should be capable of self bleeding over time. You'd basically just need to keep checking the coolant level and keeping it topped off.

-Rod

thank you everyone for your responses i found out what my problem was it was the lower hose crimping up do to it being soft and figured out how to bleed system u need to raise the car as high as possible in front and turn heater on high on floor and just keep dumping antifreeze in until it is full and no air bubbles