Question about water temp sensors

[GaPchNCrm]

OK I had a radiator leak a few weeks ago- yeah I was supposed to get pics but didn't because it became VERY clear that a new radiator was a must so I just got a new one put in. I drove it to work and had to stop and refill it 4 times, and I only work 20 miles from home. It ran pretty hot a few times for very short periods of time... like only long enough for me to get pulled over and shut it off. Anyhow, got the new radiator and all, but I am having conflicting readings from my water temp gages. My aftermarket one is reading high, like around 250. My factory one shows slightly below straight up and down. The truck runs fine but I'm scared to drive it.... Its not losing water. Is it possible that the sensor to the aftermarket gage got fried? How would one test this? Put it in simple terms for me please lol Thanks!

 

[discbrks]

You could always take out the a/mkt sender & stick it in a pot of boiling water. As long as its between 210-220, I would say its working fine.

Is it possible that you have a steam bubble in the system?

 

[Agnem]

Tanya, Take the radiator cap off, and let the truck come up to operating temp. Put a meat thermometer or something like it in the radiator cap opening, and see how the mechanical reading compares to your aftermarket one. Yes, it's possible for a sender to go bad.

 

[argve]

I suspect that you have an air pocket in the system... burp it...

Now you ask how to burp your truck...

first always talk nice to it...


Lay truck over your shoulder and pat it gently on the back of the cab...


hee hee hee


First fill up the rad and make sure that it's full all the way - then just make sure there is something in the reservoir.
pop the rad cap loose - but not all the way off you want it to vent to the overflow reservoir but not all over the top of the rad.

Then start the truck and let it just idle - let this go on until it reaches normal operating temp (aka the thermostat opens up) let it cycle around the fluid for a little bit - it will shove fluid and the air out of the rad into the overflow rez...

Now shut truck off, and close up the rad cap.

Keep an eye on it while it cools down and make sure that reservoir doesn't go empty you don't want it to suck air into the system while it cools.

As the truck cools down the fluid will contract so it will pull fluid from the reservoir to the rad.

I actually prefer a lever type cap for these procedures instead of the normal turn it half way type only because it's easier to work with not that it won't work....

Sometimes if the air pocket is large enough I've had to run it up in rpms while warming up to get the fluid to cycle around properly but that was only once on the E. I could tell because the temp wasn't moving while warming it then once I started reving her up the temp spiked but came down pretty quick.... I knew right then and there it was a air pocket that was causing the water pump to cavitate.

But if you do decide to throw Peppermint on your shoulder - I WANT PICTURES!!!!

 

[GaPchNCrm]

Travis- don't you have a Dodge forum to go hang out on or something?? lol

Thanks Mel and Disc... I'll mess with it this weekend when I have time to print Travis's instructions off and study them =))

 

[towcat]

tanya-
these motors are a bear to burp when they get air pockets. why? the thermostat sits below the cylinder head.....
I do what goatboy suggested and take it one step further.
find a steep hill or loading dock and point it uphill as you are cycling the cooling system.
works much faster that way.
I cheat, I use towtrucks to lift the front end of the vehicle I'm burping

 

[GaPchNCrm]

TC- My driveway is pretty steep, I guess that would do the job. Thanks!

 

[icanfixall]

Another way is to remove the heater supply hose from the passenger side head. Then fill until coolant comes out the hose. Still burping is going to be needed. I do what towcat does. My driveway is just the right angle. Its important that the overflow hose is free of crap. If its just slightly plugged you will get coolant into the resivour but it wont make it back into the radiator when it cools down. Burping the trapped air can take a few heatups and cool downs over several days. Just keep an eye on the overflow tank level. Don't let it go MT or you will be sucking air back into the system. Also that small hose needs to be tight on the radiator fitting so no air is drawn in there.