Ok, new guy here Ill take my beatings as they come. Any thoughts would be appreciated though. Ok 03 4.7l Durango. 119,000 on it. 2 months ago over heated after gettin off freeway onto surface street. Shut it down, waited, no leaks found, res bottle full. Nursed it to shop about 5 miles away. Put coolant in it, ran it for a while, did block test nothing wrong found, said possible rad cap was the only thought. Changed cap, flushed system and drove it for a moth, no problems, even towed a boat 800 miles without the gauge even movin. Ok gettin ready to head out of town, sittin runnin over heats again, pulled into parking area, rad cap cold, open it up, a little spew of antifreeze bops out, put cap back on, res bottle full, and is now back at the norm temp for this thing....just under the half mark...Run it back down to shop insist they put new stat in..they say the pressure tested it, was good, did another block test good...Ok, a week ago noticed the upper hose buldgin a bit, so had shop replace it..while bleeding it seemed like it was taking forever, got it down to just tiny little bubbles coming out of bleeder screw..ok there you go kid. I took it home and bled it a bit more myself. Now take it on about 300mile road trip last night, look in res bottle, its full, pull cap off and just a hint of coolant at bottom of hose. Ran it for about 15 mins, open the bleed screw, nothing coming out of it but air. Could this be air still trapped in system or am I lookin at possible bad head or head gasket issue here? No coolant on oil and no oil on coolant found. Runs like a champ and doesnt miss a beat. Any thoughts????

 

huh ...and now after having the cap off for a bit this morning.... coolant level in upper hose good and res bottle down to 3rd or 4th dot..open bleeder screw, little air bubbles for 2 secs then coolant...this thing is driving me nuts or is this how this system suppose to work, but would it be normal to have a little air in your coolant system?

 

Air in the system will cause all of these issues. I wonder if the pump is on the way out. Make sure the heater is on hot and on HI when doing your bleed.


The WORST thing you can do is overheat that motor! The 4.7L has aluminum heads and a cast iron block. The block expands at a different rate than the heads and during an overheat situation the head gasket is blown.

Having a pressure test of the system and a compression test both coming back fine (I hope that's what you mean) then I would go to the pump.

Did they replace the T-stat?

 

The block test was with that blue liquid in the bulb sniffin for exhaust fumes in the coolant ...the liquid didnt change color so they said it was good. They also pressure checked the coolant system and said it was fine, so could be the water pump grabbin air? No leaks or squeals from the pump, but they dont always do that when they are going bad though. Thanks for the input!

 

Please learn from my experience in October. GET IT FIXED!!! DO not mess around with this on the 4.7 and at 119K I would start with the basics.

Water pump, thermostat AND Both upper and lower hoses.

Complete cooling system flush including back flush of the heater core. Make sure they also drain the block plugs. Each side of the block, basically a bolt on drain plug not to be confused with the freeze plugs..


Check the radiator, when they take pump off look at the radiator for signs of internal failure, swelling, you will notice, in my case the internal cores split and the casing split. Photos available if you are interested, PM me.

At 119K for the fairly reasonable cost even if the water pump isnt the problem it is definitely good insurance.


Summary:

WATERPUMP I recommend Bosch, I think you can get them at Advance ore Autozone, if your mechanic can get them it would probably be worth a few more bucks but thats between you and them.

Thermostat, You are at the housing for the lower hose r/r whats another few minutes.

UPPER AND LOWER HOSES

Serpentine Belt. I recommend GOODYEAR GATORBACK A little pricy but good and they last.

Good coolant flush including back flush of cooling system.

The biggest advice I can recomment is DO NOT USE PEPBOYS Seriously I think once you read the link it will be pretty obvious.



I am enclosing a link to my troubles with the cooling system back in October. This might shed some light again if you need photos PM me...


https://dodgeforum.com/forum/1st-gen...lis-bound.html

 

Wow Magic84, that is one heck of an adventure there! Well they did replace t-stat when I asked them to. Its not over heating...not yet anyway, just got this funky coolant bottle not draining back into system thing goin on once in a while and seems like air in the system...who knows..1 question though...I did have the exhaust manifold gasket replace about 3 weeks before this happend, is there anyway they could have screwed up the head on that side with replacing that? I dont think so, but you never know. But if that head was goofed, I really dont think I would have drove from Sacramento to Seattle towing a 19ft jet boat with no issues at all and the gauge not even moving.

 

That's good because that's one issue down to the puzzle.


Most likely because the system isn't bleed correctly so make sure the heater is going during bleed.


No.

The manifold is on the outside of the head and they would have had to remove the valve cover to even gain access to the head bolts. Most likely they would have not done this because of the pure hell to get em off in the first place.

This is correct.....IMHO

To me it sounds like you let the reservoir run dry or you have a bad rubber hose to the reservoir. Replace this hose! It runs between the reservoir and the radiator cap. If there is a tiny (I mean TINY) hole in this hose it will pull air and pass antifreeze. If either one of these issues happened this would allow air into the system causing the issue.

 

well some bad news....went to rad shop today, thought well might just have the waterpump and clutch fan replaced just because of the mileage...was talking to the mechanic about all of this and he asked if he could check the coolant system with his sniffer as to the standard liquid in bulb block test............sure enough ....hc in the coolant system......said this is sure sign a head gasket is on its way out the door, just in an early stage......oh boy....

 

Read my reply on the 98 5.2 Overheating. I have been a mechanic for over 30 years and have never heard of an HC sniffer before for radiators but then again I could be wrong. Only sniffer I have known about is the one for A/C and that will not sniff out HC in a system. The only other HC sniffer I know of is the one that goes into the exhaust for Emissions Testing.

 

Mike, that is a pretty serious diagnosis. I would definitely get a second test on that one. During my overnight in Toledo that was the diagnosis from the Honda dealer and it turned out to be the radiator, still pretty pricey but a lot cheaper than head gasket. Situation may be different since I caught mine a lot earlier but check it out soon.