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I have 2002 Dodge Durango 4.7L Second times Overheating. I changed water pump, changed 3 times thermostats, changed 3 times radiator caps. Today after warm up and drove about 2 miles, it’s overheated. There is no leaks. When I added coolant, I got heat in the front roll but not the rear. the temp. gauge is at slightly less then normal marks. Every two weeks, I checked the upper hose, no coolant. There is coolant in the coolant recovery tank. I have not done the vacum test. What is your suggestion?
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see if this helps. You may have air trapped or a clogged heater core.
http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats
http://www.justanswer.com/dodge/0lowu-dodge-durango-2002-no-heat.html
http://www.justanswer.com/dodge/0ynev-2002-durango-rear-heat.html
So you are losing coolant? Do a pressure test of the system to check for leaks. I would also check for cross contamination with engine oil.
Knowing a little bit about that engine, I can tell you where I’d start. Time to perform a combustion leak test. 4.7L and 3.7L family of engines are notorious to not liking to overheat at all. Even once, and you could be dealing with a warped/cracked head and/or headgasket issue. Further that, the valve seats are notorious for coming loose once it has overheated. Did you make sure the air bleeder ball on the thermostat is at the 12 o’clock position? Did you use an air lift to fill the coolant system? Those could both be causing an over heat problem, especially if the wrong coolant has been ran as a mix in the system, however I would not waste another minute chasing anything until a combustion test has been performed.
The early 4.7s were bad for failed cylinder head gaskets. I have done a few of them. After all you have done checking for combustion leaks should be your next step.
Thank you for your help. I got the car back home. I added more coolant, change the radiator cap, ran it for 45 minutes, shutted it off for the night. In the morning, I check the upper hose, it seems firm (I assumed pressure holds). I ran for 2 hours no troubles. The car rans fine but the temp gauge is not working. It stays at C and or at 1/4 and dropped back to C. The heat is working for the front but not the rear. In the evenning, I checked the upper hose again. It seems soft ( I assumed it has lost it pressure). No leaks, Oil is clean, no smoke. I will do the pressure test next time when I save enough money.
I seem to remember having issues with the older 4.7s having trapped air pockets behind the plastic thermostat housing, as it is the lowest point in the system. I am not saying this is your case, but it very well may be.. I remember there being at least one bleed port on the top of the engine by the upper radiator hose as well. May want to give that a try first.
I know this is OLD but in case anyone runs into this issue. The 4.7 durango (mine is a 2000) has a bleeder screw on top by the engine block near the top hose. The hose with the thermostat cap. That bleeder MUST be opened when refilling. You refill via the cap not the reservoir tank.
This is from factory manual on draining btw.
“On the 4.7L engine the thermostat is an inlet side thermostat. This means that the engine coolant will not drain when the radiator drain petcock is opened. It will be necessary to remove the thermo-stat housing and thermostat to allow the coolant trapped in the engine block to drain. ”
After loosening the hose (at the bottom) and taking thermostat out, Drain the block plug.
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