Sick of changing thermostats and unpredictable overheating "issues". Here is the digest version, the blow by blow history follows below.
Third time the thermostat has gone bad and won't open, causing the engine to rapidly overheat, triggering the "check gauges" alarm if I'm not watching the temp. The last time blew the head gaskets and necessitated a top end rebuild. If I pullover and wait a couple of minutes, till the bubbling and popping in the upper radiator hose settles down (even though there was no pressure release of fluid) the coolant temp (gauge) will now be back to normal. I can tell it's just the thermostat failing to open soon enough, even though it's been fine for over a year since I replaced it - the second time. It does have the dongle, and installed toward the top, but then even when open, the temp is closer to 2/3 hot, not just below half as what was normal previously.

History: 2003 RAM 1500 2WD with A/T and over 150K with no problems except the auto trans pressure regulator needed replacing at about 90K. I loved much about the truck except the poor ride quality. When I noticed it using (loosing) coolant I traced it to coming out the bottom of the water pump so I assumed it was either a bad bearing, seal, or both. So I ordered a new pump, hoses, belt, and of course as suggested changed out the thermostat as recommended, even though it had never overheated in N. CALIF where it often gets high 90 degrees in the summer.
When I removed the water pump I noticed that a washer on the very bottom bolt fell off in pieces. It had somehow corroded and become brittle and crumbled to the touch. Further investigation showed that the pump and seal were not the source of the leak, but the area behind this washer. Oh well, after 2+ hours to get to this point, might as well change out the pump, and all else, including fan belt idler + tensioner.

A few weeks later the overheating began. At first it was just a short trip of about 1/2 mile and the gauge was pegged. Pulled over and everything looked fine, hose and cap were not hot. Got back in, turned on key to check guages and it was magically down to well below half. I thought it must be an electrical issue, or the computer acting up. (Since I've had the truck, 2nd owner who bought with about 56K on it, It would maybe every month or two have an issue where not all cylinders would fire. It was usually remedied by simply shutting engine and restarting. This in NOT a multiple displacement model. It has also also gone for over a year without producing this issue.)
It only did this occasionally, so I mostly ignored it because I wasn't able to find sure diagnosis on line. I had read about the burping issues and was certain it wasn't that yet still underwent a thorough process to eliminate that as a possibility. Then one time it acted up quickly on the interstate with my wife and some cargo in the back (not her though). The alarm caught me by surprise and I was unable to quickly pull over to a safe spot to check. Well it did boil over and I let it cool, added some water and back on the road. Happened again, same trip, but this time bad. Some days after that I notice the smell of antifreeze in the exhaust, and as the head gasket got worse it was causing starting problems.
So during the top end rebuild which was previously not needed (I hadn't even experienced the "tick"} I realized it was the new Stant thermostat I had put in. Brought it back to the parts store (hoping to find a recall and maybe class action suit) and they told me the company had gone out of business, but happily gave me another. This time I got a lower temp 195 degree unit to put back in when I got the heads back from the rebuild. That was almost 2 years and 10 or 12 thousand miles ago with no problems until a week ago and hear we go again, except this time the stat never does open all the way.
It's not much work to pull the stat and I've thought about pulling out the stupid dingle dangle and drilling another hole, but its not even opening all the way any how, so I'm looking for suggestions on a good quality stat, and whether the dongle is even worth having.
I guess I understand the reverse flow coolant and everything, but why in hell did Dodge ever decide to pull coolant from the top of the tank?
PS. Ever since the rebuild, my truck now has the tick.

 

What brand thermostats are you installing??

 

the one that really screwed me was a Stant, the last one I don't remember. Whatever the part house gave me, probably Motorad, a lower temp 193 or 195 F that worked fine for like 2 years. I'll have to check later if I can find the box. I've found a Colarad 192 that I like at Rock Auto, but don't reallly want to wait for shipping. Local parts houses don't have much selection, mostly Motorad. At least Napa lists the manufacturer on their website. With Autozone you dont' know what you're getting with their Duralast brand.

 

Stant is MotorRad, (bought out stant)

Drill a 1/16" hole in the stat outer flange so coolant canalways bleed thru & use a higher mix of coolant over water. 50/50 to 60/40

 

Yeah, I suppose they also make the A***zone products too. The one that just failed has the weep hole with jingle pin.
Why do you think higher A/F ratio will open the stat any sooner? the truck doesn't have an overheat problem when the stat works.

 

if the stat sticks shut, the hole will allow that small amount of flow & put hot coolant on the back side of the stat. I've done this for years and the only time I ran into a problem was on the '05 diesel with a 1/8" hole, that was too big and it thru a code for taking too long to come up to temp. Otherwise it removes the risk of air pockets on coolant swaps. The jiggle pin can be useless in some installs (like on the ram where the stat is flat & the pin is always closed).

I dont know the hemi motor (yet) but expect if you went to a 180* stat & programmed the e-fan to come on at 195*f (like I have done on the Dak) you will have no problems. I monitor my engines (both of them) every drive (see pic below) and know exactly what the PCM is seeing as I roll along. ON the Dak with the 4.7 motor, I addressed all of the issues known to give that motor a bad rap, (spun bearings, overheating & sludge) and went on a mission to pull as much power out of the motor without cams & head work. I'm down to 1 mod left, the cat back exhaust. Once that is in, the only things left might be fresh ported heads & HO or '08 cams, if I go that route then would probably swap the engine for an HO engine.

If looking to get the engine to run cooler & more under your control, consider the HP Tuners MPVI3, I think they are around $400 for the base version, pro is something like $700. I have an MPVI2+ (obsolete) and no plans to part with it (they offer upgrades on tradeins), no need as it covers the 3 rides we have in the house.

 

Thanks for the info, but I am not a tuner, but an ex-mechanic. This RAM is just our family run around multi purpose unit.
So it looks like my idea of just removing the dongle and leaving the hole would work? Of course I'd have to buy a new unit
due to the high heat destroying the present stat. Maybe I'll drill another one and have two bleed holes.
Why does the stat not open when the temp is so high? I know the coolant in the upper hose (the engine inlet I suppose, since its flow reversed?)
is trying hard to get through the stat, but it takes a few minutes of "popping" and shaking as the cooling slowly seeps past the stat
into the block. Weird thing is - the coolant has not over flowed. When I replaced the failed Stant stat (after doing top end) I did use
a 192 degree unit, which put the gauge needle a click below the middle of the guage, which I liked, just lower than the dead center
which was previously normal. I'm not gonna go lower than 190 because i'm in CA and don't want to trigger error codes, etc.
I also don't have and e-fan, but considering the swap - maybe you can recommend a method for that.
Also loved my old Dakotas !

 

Back when I was working on my volkswagens..... I would buy three thermostats, to help ensure I got one that actually worked..... More often than not, I ended up going back to the parts store, for a fourth, and sometimes fifth thermostat...... Granted, that's been quite a few years ago, but, part quality has not improved since then..... it has actually declined with all the buyouts and mergers..... Finding good quality parts, that actually do what they are supposed to these days, is a real friggin' crap shoot.

 

If your cap is not allowing fouid into the overflow bottle it might be bad. It should take hot coolant and suck in cold coolant. Fwiw, i run a 7 psi cap on the diesel ram ( no heavy loads) and a 13 psi cap on the dakota. Since i always monitor the obd port, i have no worries and can be proactive if needed

 

I'm new here, but my 06 ram 1500, 4.7 is overheating after my right side head lost a lifter column, I've replaced both heads, head gaskets, all lifters, rocker arms, all gaskets, and o rings, new water pump, new timing chain, new thermostat and housing x 2, bled the system, new radiator, and still overheating. What did I do wrong, or not do?