A couple days ago, I noticed my Engine Coolant Guage on the cluster was not moving at all until warmed up and driven a few miles. Then it would move from cold to not even half way all of a sudden and fluctuate slightly. After turning truck off for a few minutes and turning it back on, the needle would be all the way down at cold again.

Today I changed my thermostat and the needle moved up after letting truck run for 10 minutes. I know these 3.0 motors take a long time to warm up (no i dont have an efan). I had good heat after being wamred up.

Is the thermostat sending unit the same as the Engine collant temp. sensor? I replaced that a couple years ago.....maybe that is messed up again.

I'll be driving the truck tonight and will watch the needle.......

 

Have you flushed the whole system or just change the thermostat?

 

i just changed the thermosotat.......for now.

 

howd the antifreeze look?

 

pretty bright green.....IMO

 

Update: Well guys when i start up the truck now, it takes a few minutes for the needle to start moving from cold.

When the truck is fully warm, the needle reads over the N orO in normal, and fluctuates lower when turning off heater and defroster.

so it is still flucuating.....but atleast not overheating.....and other ideas for the fluctuation?

new ect sensor?

 

Check the voltage at the battery at idle. Post what it is .

 

Is the coolant system gurgling after you shut the truck down? Have you tested the radiator cap?


Also, have you started the truck (while cold) with the radiator cap off, then let it run and burp the air from the system?


GB :)

 

maybe its just because its so cold out.Temp fluctuate and the thermostat is doing its job.

 

all i have done is change the thermostat and top off the radiator.
takes forever to warm up the truck from being cold.....the needle moves ever so slowly....i have heat out the vents.....but needle fluctuates from 45% (between the N and O in normal) down to about 25% on guage while driving.