all I did was change the T-stat

[firstx]

Now my temp. gauge goes 1/2 way up and 1/4 way
down...back and fourth...I'm going crazy... because it
didn't do that before I change the stat... Its been 8
days already I figured it had air in the system and
it would go away on its own.

Can anyone shed some light on this for me PLEASE

Thanks
BOB

 

[Blee1099]

Originally posted by firstx
Now my temp. gauge goes 1/2 way up and 1/4 way
down...back and fourth...I'm going crazy... because it
didn't do that before I change the stat... Its been 8
days already I figured it had air in the system and
it would go away on its own.

Can anyone shed some light on this for me PLEASE

Thanks
BOB

I usually turn on the engine, pop the radiator cap off, and start filling it up with antifreeze while it reaches normal temperature. Done that everytime I've changed my thermostat with no problems.

 

[410Fortune]

It is possible you have air in the system.

It will not go away on its own.

Have you gotten the truck up to tempature, and the problem is still there or no?

Ford gages are not known for their "accuracy".

Also is the temp gage the only 1 acting funny?

 

[firstx]

Done that the day I put the stat in... also put more
antifreeze in reservoir just in case.

Lost a little antifreeze from reservoir thats it...the truck
runs fine..just don't understand the temp. gauge
going up and down.

Thats what driving me CRAZY

Thanks

BOB

 

[firstx]

410Fortune

Thats what I thought too..air in the system..how do you
tell when all the air is out

the trucks been up to temp. for a week now
the gauge goes up and down never past half

the temp. gauge is the only thing acting up

THanks

BOB

 

[Blee1099]

Originally posted by firstx
410Fortune

Thats what I thought too..air in the system..how do you
tell when all the air is out

the trucks been up to temp. for a week now
the gauge goes up and down never past half

the temp. gauge is the only thing acting up

THanks

BOB

If you feel you have air in your system, you can loosen the bleeder screw on the radiator till you start seeing antifreeze coming out of it. Once you see the antifreeze, just tighten it back up and check the radiator to make sure it ain't running low.

 

[firstx]

Didn't know it had a bleeder screw...where would it
be at
thanks Blee1099

 

[Billy177]

since you have driven the car for 8 days chances are most of the bubbles have worked their way to the top. with the engine cold pop the cap off the fluid will probrally be lower then you last checked. just top it off and check again the next day.

 

[firstx]

Fun thing is I been doing that for the last 8 days

That's why I'm so puzzeled about the temp. gauge

Thank you Billy177

BOB

 

[Opera House]

Sorry Charlie!

That symptom is consistant with putting the stat in backwards. The wax bead in not in the engine flow so it runs hotter till it opens and then closes. This gives wide temperature swings.

 

[firstx]

Opea House

There's only one way to put a stat in and I'm possitive
I put it in right

Plus when I took the old one out..the hole was on the
bottom not the top like it should be

that also puzzeled me

thanks

BOB

 

[firstx]

sorry should of said the spring end goes towards the
the engine

BOB

 

[410Fortune]

I too am not aware of any bleeder screw ???

OKay so we have established that you are sure you put the new stat in the proper way, correct?

Is it possible that you maybe moved the wires leading to the temp sensor while you were in there?

IIf there is air trapped behind the T stat one sure fire way to get it out is to remove the hose leading directly to the T stat and pour hot water down it.......this is a long shot.

I think you need to go buy another thermostat and install it.
I typically buy 3 of them at a time, and hten I boil them in water on the range with a thermometer.
The stat that is fully open at the target tempature is the one that goes in the truck.


Even if you are 100% sure that you put it in the right way, there is sonmething wrong, and the problem started with the new stat correct? so thats where you need to start troubleshooting.

 

[firstx]

410fortune

Your right I should change it again to see if that works
its to simple not to

Thanks for all the info.... you guys are great

Thanks

BOB

 

[Fusion213]

Mine did that when I changed the t-stat, it was bothering me so I just bought another one and the temperature wasn't fluctuating anymore.

 

[FordLover]

Thermostats suck.. I replaced mine, it was running fine before I did it, just changed it as preventive maintaince. The new one must be runing wide open because the truck never heats up, and barely puts out hot air from the heater.

Anyone have a short cut or easy way to change it out in the ol 4.0 OHV motor? I'm gonna pull mine and put the old one back in.
-Martin

 

[james t]

Originally posted by FordLover
Thermostats suck.. I replaced mine, it was running fine before I did it, just changed it as preventive maintaince. The new one must be runing wide open because the truck never heats up, and barely puts out hot air from the heater.

same here, i changed mine at the begining of summer as a preventative maintanance with other things. here it is 6 months later, and i had to change it agian because the new RobertShaw 'stat was stuck open. at least i have a heater again.

 

[SR77]

So where is this bleeder screw located at to release the air in the system? Thanks

 

[witchdoctor]

sometimes a new tstat will stick closed when it is first installed. this also causes temp fluctuations, because not all of the coolant is circulating even though you have filled it up.

a mechanic showed me a trick to avoid that. you pull the tstat slightly open, and stick a paper match into the gap on opposing sides. cut off the excess part of the matches. it will leave you with about a 1/16 gap.

then when you install it, the water flows until it reaches temp. the match pieces then get flushed out and they dissolve into the coolant.

 

[410Fortune]

SHORTCUT for the OHV 4.0L Thermostat bolt

Okay so as you guys know there is that one bolt on the pass side of the thermostat housing that is a BIT&* to get at.

You have 2 choices to make life easier:
1. use a 1/4" drive and wobbly with a shallow 10mm socket. It's a PITA but you can get it in there if the socket is shallow enough.

2. Use a 10mm wrench, open ended and go from behind the alternator. You can get your hand in there, it helps if you already disconnect the radiator hose. THis is one of those turn the bolt 1/8 of a turn, flip the wrench over situations. It makes your hand hurt bif time, but with patience it can be done quickly.

Now the problem with this SOB bolt is the lower intake is aluminum and it is VERY easy to get the sucker in crooked or strip it out.
Use lots of light and if you need it stand on something so you can get up in there.

I have found it VERy necessary to have a magnet handy when trying to get this bolt back in, I usually drop it 5-6 times beffore I get it started, and when it falls, it likes to go right under the fuel injectors. You can even setup a piece of cardboard so the bolt cannot fall into the engine if you want.


Thermostats do suck. THis is why I buy 3-4 of them, take them home and test them on the stove prior to installation. Usually 2 of them will work okay while one sucks. I return the ones I dont use.