[Kmoloney]

I am really at a loss as to where to go next.

What I have:

2006 Durango SXT, 4WD, 4.7l, 179k miles

My Issues:
-Instantly overheats when driving
-Heater blows mostly cool air

What I've done in the past 2 weeks:
-Replaced thermostat
-Replaced water pump
-Replaced radiator
-Replaced radiator cap
-Flushed cooling system
-Flushed heater core

Other information:
Checked dipstick for milky white oil and tested radiator splash up at startup to determine if bad head gasket. Both tests checked out fine. No white smoke either.

I am at a loss here. I've done absolutely everything I can think of except replacing the heater core. Any help is greatly appreciated. This is my daily driver and it's down and out. I've spent so much on parts. What am I missing?

 

[tomk]

radiator fan runs?

what does "overheats" mean? temp gauge? blowing coolant?

 

[Kmoloney]

radiator fan runs?

what does "overheats" mean? temp gauge? blowing coolant?

Both. As soon as you begin driving , the temp gauge goes to red, the temp warning light comes on, and the coolant gets so hot you cannot remove the radiator cap.

 

[Chase300]

Did you "burp" the system after refilling the coolant?

 

[Jim1590]

Did you "burp" the system after refilling the coolant?

Plus 1 on the burping. Get one of these:

https://www.amazon.com/Lisle-24680-...dp/B00A6AS6LY/ref=sr_1_1?ie=UTF8&qid=1466042995&sr=8-1&keywords=Radiator+funnel

I wouldn't fill a rad without it now.

Have you tried to bypass the heater core? Is it possible in the durango? I have done it in a ford explorer. Thinking on that, isn't the core just an offshoot of the cooling system? It should not do much to the cooling ability unless it was leaking. Maybe check the belt? Is it slipping causing ineffectual fluid movement? Just a stab in the dark here.

 

[MWeed]

Have you replaced the radiator hoses? Have you run a gas check on the coolant to see if there is a head gasket leak? Is the thermostat in the correct way? Is coolant at the proper level?

 

[Chase300]

Sure sounds like you have air in the system.
Did you remove the bleed plug when refilling with coolant?
If not, its the hex head plug next to the fill cap on the upper hose.
You have to remove it when refilling the coolant to get the air out of the system...keep filling until coolant flows out of the bleed port then replace the plug, top off and put on the cap.

 

[Kmoloney]

Did you "burp" the system after refilling the coolant?

Yes, I bled the system by unscrewing the bleeder screw.

 

[Kmoloney]

Plus 1 on the burping. Get one of these:

https://www.amazon.com/Lisle-24680-...dp/B00A6AS6LY/ref=sr_1_1?ie=UTF8&qid=1466042995&sr=8-1&keywords=Radiator+funnel

I wouldn't fill a rad without it now.

Have you tried to bypass the heater core? Is it possible in the durango? I have done it in a ford explorer. Thinking on that, isn't the core just an offshoot of the cooling system? It should not do much to the cooling ability unless it was leaking. Maybe check the belt? Is it slipping causing ineffectual fluid movement? Just a stab in the dark here.

I have not tried bypassing the heater core. What would be the procedure on my Durango ?

 

[Kmoloney]

Have you replaced the radiator hoses? Have you run a gas check on the coolant to see if there is a head gasket leak? Is the thermostat in the correct way? Is coolant at the proper level?

Coolant is at proper level but there appears to be no flow or circulation of the coolant. The coolant in the reservoir never goes down. It just stays at the same level. It's as though the coolant is not circulating at all. Thermostat is in correctly with the spring side towards the engine block. Have not changed out radiator hoses. They appear good and solid with no cracks, holes or collapsing.

 

[Kmoloney]

Sure sounds like you have air in the system.
Did you remove the bleed plug when refilling with coolant?
If not, its the hex head plug next to the fill cap on the upper hose.
You have to remove it when refilling the coolant to get the air out of the system...keep filling until coolant flows out of the bleed port then replace the plug, top off and put on the cap.

Interesting. Yes I did remove the bleeder plug at the upper hose witha hex wrench but throughout the process, coolant never comes out. Just steam and occasionally small spits of coolant. Could we be onto something here since the reservoir never goes down and a flow of coolant never comes out of the bleeder hole?

 

[Kmoloney]

I just read this post on another forum

"...the heater core has no bearing on overheating conditions (except to help drop the temperature by cranking the heat). Bypassing the heater core will NOT stop it from overheating in any way shape or form.."

 

[MWeed]

It could be a faulty stat. When engine overheats is the radiator hot? Stat could not be opening at all.

 

[Kmoloney]

I failed to mention that the clutch fan was also recently replaced. I'm thinking that there is some kind of blockage that's preventing flow to the engine block for cooling since the reservoir never goes down and the fact that a solid flow of coolant never comes out of the bleeder hole. The question is, how do I get this coolant to flow and circulate?

 

[Kmoloney]

It could be a faulty stat. When engine overheats is the radiator hot? Stat could not be opening at all.

I just installed a brand new Mopar stat that I purchased from the Dodge dealer after installing and then removing a brand new after market stat from Autozone. Am I just having bad luck with brand new stats?

 

[Kmoloney]

Sure sounds like you have air in the system.
Did you remove the bleed plug when refilling with coolant?
If not, its the hex head plug next to the fill cap on the upper hose.
You have to remove it when refilling the coolant to get the air out of the system...keep filling until coolant flows out of the bleed port then replace the plug, top off and put on the cap.

Well I'll be damned. I got it. Chase300 was right on the money. I reread your post about air in the system and realized I wasn't bleeding it at all. I just opened the bleeder screw and was waiting for coolant to come out while running the engine instead of filling the radiator until coolant came out. After doing it the right way, I'm pleased to say that the problem is solved. Woohoo! Thank you kindly Chase300. You just saved the day! And my sanity!!! I owe you a steak and a beer! Kudos my friend...kudos!

 

[Durangutan]

Well done Chase. You beat me to it. Reminded me of my Intrepid and the same issue.