So, I changed my coolant a little early because I'm fussy about maintenance with my truck...its expensive, and its an investment. So, drain the coolant, (I was only going to drain and refill as the coolant looked good coming out). Coolant goes back in and I start it up to check for the overflow to suck whatever the rad needs back in (as per manual, fill rad as far as you can and use overflow from there). Funny thing was that not much went back in the rad, then when I started up to get it up to temp, the upper rad hose would not get hot (right at operating temp, too). So, I turned the heat on...no heat. Thermostat failed. My suspician is that it would have failed anyways soon, (maybe) but that the sudden temp change from changing coolant accelerated it. So there I am on a Friday night knowing that no dodge dealer would change it on the weekend (still under warranty, too) running down the street to get a new thermostat...put the new one in and everything's fine.
This ever happened to anyone, or is this just a fluke?

 

Air Pocket?

 

You had it airbound. Try unhooking the coolant hose from the top of the t-stat housing and letting the air out.

 

I had the same issue. Air pocket. Took it a little while to bleed the air off, then everything was fine. I had replaced t-stat about 2 months earlier. Thats when I noticed the coolant wasnt the orangest any more. Replaced it a couple months later and same issue. Run it with thte cap off, and the heat on high until you get heat. Then top it off, and should be good to go!

 

Everytime I change or do something with coolant I always let it run and warm up to temp and then it'll go to twards the hot side then all of a sudden it'll go down to normal temp! It just needs to burp! On my CTD it always take a bit longer due to diesels running cooler at idle Good luck Sir!

 

Thats funny because in the manual it says it has two one way check valves that bleed air, and that you have to run the engine with the cap on until operating temp and add through the overflow. I guess the emanual which isn't that great to begin with) isn't always accurate.

 

I don't think I caused any damage, as there was still coolant in the engine and it didn't overheat, but is there possibility of causing harm when running the engine for a few minutes with an air pocket like that?

 

I usually pull one of the small plugs on top of cylinder head. Fill radiator with coolant until it comes out hole. Then reinstall plug fill radiator and your done.

 

I doubt you hurt anything...

I've found that sometimes I can get some of the air out by repeatedly squeezing the top hose.