i have a 04 dodge ram 1500 with the 4.7 v8 with 44000 on her, thermostat was stickin on her and i changed it out with a aftermarket one same 190 degree temp..... well my problem is that my gauge moves back and forth usually the width of the needle on the halfway mark( not where it normally sat) and every so often a little past it, but never even close to runnin hot not even at the 3/4mark....well took it to the dodge dealer and had the system bleed thought there was air trapped in the system or a sensor.. well its still doing the same thing so i took it another mechanic shop and had it looked at and said it was normal to move a little..... well it never moved before..... well i drove it into town last night 20 miles and it sat at the halfway mark and didnt move and had the a/c on, well soon as i got into traffic it moved past halfway(in between halfway and 3/4s) and just sat there, when leaving town it did the same thing untill we got out and got on open road where it went back to halfway,( turned the a/c off for 5 miles and had no effect on the gauge) dont know what to do about to pull my hair out.... everyone tells me theres nothing wrong but i know better, i think its the temp sensor but i dont know!!!!

any info would be greatly apprecaited!!!!!!!!!!!!!!!!!!!!!!!!!!

 

If the temp goes up while you're idling I may look at maybe a clogged radiator or maybe your water pump going bad but I would lean towards something clogged. I would tend to believe that if the temp goes down while you're driving it's being cooled by the air being forced over it while moving. You sure you have the proper mixture of coolant and water?

 

sounds like a bad mix or a clog to me . like johnny said

 

put the 50/50 mix back in it, and it only did it in heavy traffic,

 

I have had two bad thermostats on my other vehicle recently. Run the heater to purge any trapped air. I would change the radiator cap. And if it still wasn't acting right I would remove and test the thermostat in a pan of boiling water. If I still didn't like the way it opened I would replace it.

 

ill give that a try...

 

how do u check for a clogged radiator

 

That is hard to determine, What I do is run my hand over the radiator to see if there are hot or cold spots. This gives you an idea if there is consistant flow or not. Good luck...

 

Yeah,I've got the same problem also.I've had it for about 2 years now and I've replaced the t-stat,rad cap,coollant,and the radiator.Even blead it about 10 times.And i even installed an e-fan, Still has the same effect.I talked to a guy i know at autozone about changing out the temp senser.(yes, I know there not the smartest people in the world when it comes to everything cars/trucks)He seems to think that since it's a newer truck it shouldn't be a problem it might be a wiring issue,IDK.I've hooked up my 3815 and watched the temp and the highest it got to was 211.I'm still leaning toward the temp sensor.If you find out what caused that,Please let me know so i can see if it might be the same issue with mine.

 

checked the radiator for hot and cool spots and it was just fine..... when the temp gauge starts to move past halfway i can turn on the heat and it will go back to normal.... what can it be?