Overheats when driving?

Overheating in motion is commonly a radiator issue. They get plugged even partially and the coolant doesn't do its job. You say the heater also wasn't working, that points to the same thing. For the heater core I use CLR and a circulating pump. Basically, connect the pump, run clean water through it and drain it out. Then blow out the water and fill a bucket with CLR, let the pump pull in the CLR and circulate it through the core and back to the bucket. After 45 minutes or so I use air to push the CLR out. Then flush with clear water. Now connect it back up and top off the coolant.
For a radiator the price and time it takes to swap it out usually is nothing like the cost of a heater core, so they get swapped out. You could try a flush if you have the time. A Denso radiator with HD cooling is $120.00. It takes about 3 hours to DIY removing and replacing it. You can do it without pulling the charge out of the AC system, but it's faster if you do. You can get enough room by tilting the core out of the way.
https://www.2carpros.com/articles/how-to-replace-a-car-radiator

I have a transfer pump, is that the same?

I also just this morning cancelled the heater pump lines? Did I do it right?

Ran some clr through the radiator but didn't have the right adapters to fit snug and keep all the water in. Did notice that the water came out clear and plentyfull. Doesn't seem to have obstructions.

The funnel kit boils and gargles then sucks all the water in then spits it out then I refill until full the radiator makes these crackling sounds its really weird.

Video.

Twice when test driving since it won't overheat idling it first popped off an end cap to the heater hose then a lower rad hose to the water pump. Both where slipped on the radiator hose I didn't put the hose clamp correctly.

Third test drive no hoses or end caps came off I have the heater hoses to the heater core capped off and the heater hoses to the engine connected with a 5/8 to 3/4 tee and the third outlet capped atm. I was able to make it back to base, but the temperature gauge did eventually creep over to the danger zone. Will run a combustion leak detector to single out a possible bad head gasket.

On most modern vehicles bypassing the heater is okay if the core is leaking. The problem with seeing clean water flow is that the radiator is a parallel flow core. As such you could have good flow across a 4-inch path in the top of the radiator, but the rest could be plugged solid. You could try using an IR thermometer to look at the core when it's warmed up, if you have a couple bands across it that were at say 190 degrees, but the rest was at 90 then you can see it's blocked. A bad head gasket would normally show itself a lot more because the combustion gas would not only heat the water but pressurize it as well. However, it won't hurt to rule that out.

Will do that tomorrow, thank you sir.
Kind regards, Big Vic

I conducted a combustion leak test and blue liquid slightly turned yellow.

That isn't a good sign, but I would verify it. Then you might want to look at blue devil sealant. I've had it work a few times as long as you follow the directions.

Will try this and get back. Ordered the radiator just in case its s flow problem. Someone told me there's a coolant purge valve somewhere on the top area of the engine on Dodges?

Air purge valve location and procedure?

Chatgpt spit this out.

On the 3.6 there is a bleeder on the thermostat housing. You can see it in the attached and in the first picture you posted. The normal process is to open that with a cold engine, add coolant until it starts to run out of that, then close it and continue adding coolant until the bottle reads full cold. Now start the engine and let it run until the thermostat opens. Shut it off and let it cool down. As it cools off watch the level and add coolant to keep it at full cold. Repeat the start and run process a second time. If the coolant hits full hot you are good.

Will do.

Overheats when driving.
Temperature gauge fluctuates once but then eventually overheats
Left idling for 30 min didn't overheat once?
Tried running a bars stop leak and didn't work.
Flushed the cooling system.
Burped the cooling system but didn't help.

Hi,

Has the thermostat been replaced? The thermostat on this vehicle is replaced as a unit with the thermostat housing and is a simple replacement.

If you haven't, that is where I would start. I attached the directions below specific to this vehicle. Let me know if you have already done this or if replacing it helps.

Take care,

Joe

See pics below.

Yes. Radiator cap and thermostat. Did a combustion leak test and blue liquid turned slight yellow. The weird thing is I poured a bar block sealer, and I was able to drive a bit but then a heater hose end cap came off and I made it back home. I went ahead and used the funnel kit to refill the radiator. I think I'm not burping the system correctly because if I leave the car on with the funnel kit on it throws all the water out. I think maybe the radiator is also a culprit, but I did run CLR through it and the water flow seemed adequate. Another thing is I the bars head gasket sealer which is aluminum block and heads compatible but its back to overheating when driving.

So the Durango was driving good enough after the bats block sealer its like $9 but then an end cap off dumping all the liquid. Pulled over and installed the funnel kit and added the bars leak head gasket sealer. But then it went back to overheating on the way home.

I also had previously rerouted the heater hoses going to the engine and capped the heater core aluminum lines which also have coolant flowing through them. Might have been a mistake. Maybe I connected the wrong lines and capped the wrong lines. Don't know.

Here is a reference: https://www.reddit.com/r/MechanicAdvice/s/OEVEuavs10

Connected and plugged the correct heater hoses this time. Ran a radiator cleaner. I don't know how much of the gasket sealer is in the engine but the water is clear at the moment.

The Durango is no longer overheating.

Hi,

Thanks for the update. I'm glad you got it figured out and it isn't overheating.

Take care and feel free to come back anytime in the future.

Joe

Nevermind, back to overheating. I need to order that radiator before I buy that engine.

Will mess with this tomorrow. Ordered radiator.

Hi guys. One thing I haven't seen mentioned yet is the cooling fins on the radiator. They became badly corroded on my '88 Grand Caravan causing the engine to run hotter than normal, but only above 60 mph and only when outside air temperature was over 60 degrees. I went from Wisconsin to Colorado, to Missouri, then back home like that. It never was hotter than 40 degrees outside, so the engine never ran hot until next spring. The cooling fins on the lower quarter of the radiator were either gone or would crumble away with the slightest touch. They acted like a rotten chocolate chip cookie.

Bar's Leak isn't going to help. No mention has been made of losing coolant. That product is meant to stop leaks, most commonly from radiators and water pumps.

While I've never run into this myself, I've been told there are some cooling system designs that, to work properly, require flow through the heater core. I suspect it has something to do with directing the flow of coolant to the thermostat. Regardless, if the heater core is leaking, I would connect the hoses together, not cap them off.

I'm anxious to learn the solution.

Fin corrosion can cause this, but I've seldom seen it on the trucks, lots of it on the vans though. The sealer was because of the chemical test he did showing some combustion gases in the coolant. If it is a minor leak, it might be caught in time. I don't use bars leak these days, unless it's an emergency type fix, I have seen far too many cooling systems trashed because of the leak stop fillers they use. The Blue Devil is strictly water glass. (same stuff they used to wipe out the cash for clunkers cars) I've never had it plug up a system because it only reacts to heat and air contact.

Nice. I will use that then. Thanks Steve.

I ended up connecting all heater hoses back to normal. I replaced the rad cap and thermostat. I did use bar radiator leak but also lost most of it when an end cap came off. I also used bar head gasket fix but again lost all fluid when a loose rad hose came undone. Today after connecting the heater hoses back to normal, burping the cooling system including the thermostat bleed screw the Durango drove just fine. Already put 30 miles on it and with the ac on. So relieved. Already had ordered the radiator
From rockauto and picked up the blue devil 32oz can from O'reilly's. Should I still run that?

If it isn't running hot, I would probably swap the radiator out but not run the sealer unless it starts acting up again.

Gotcha. Thanks again.