Hey Dodge lovers. My 2003 4.7l has started overheating after 135K miles. I have replaced the thermostat, still overheating. I have noticed that when the motor is hot that there is some air/coolant coming from the neck of the coolant resevoir. is this relevent. I'm not sure which way to go from here, all suggestions are welcome. Thanks for being there.

 

I know a few 4.7 owners who've had to replace their radiator at 120k+ miles. But my rule of thumb is to check the thermostat first with the pot of boiling water method (obviously by replacing yours, it's not the thermostat), then I will burp the system. Better than 75% of the time it's one of the two, t-stat or air bubbles in the system...

Proper way to "burp" your cooling system is in the FAQ section...

 

Thanks to all for the advice. I really do appreciate it. I replaced the radiator and the water pump. The water pump seemed to be fine, so I,m pretty sure it was the radiator. From what I read on this forum and what my local dealer service manager I believe the radiator was the culprit. Anyway my truck is as cool as a cucumber now.

Thanks again

Crazyhorse803

 

guess it doesnt matter now as it you have the problem solved but it could have been the radiator cap

 

The cap was the second thing I tried. Appearently the air leak at the neck of the coolant jug isn't a problem because that is the only part of the cooling system that hasn't been replaced. 85 bucks at my local dealer.

 

I just went through something smilar with my 2004 dakota with 88 k miles. Coming back from vaca (180 mile trip) My engine temp started to climb when at slow speeds. On the high way it dropped back down but would fluctuate slightly when the engine had to work over hills. When I pulled over at first sign, overflow was full with some fluid coming out. Thought a stuck thermostat. Took to get inspected and had system pressure tested. No leaks found. Was told just low on coolant, but where did it go (over flow) and why did it over heat. Asked to have the thermostat replaced assuming that was it. When doing this, they did some tests and found hydrocarbons in the cooling system. Basically, it is believed that there is a head gasket leak causing the cooling system to be pressurized by exhaust putting "air" in the system and forcing coolant out to overflow. Dealer is in hte process of replacing head gasket.

I had the truck for about a week after the initial diagnosis and coolant added, but it started to go down again with no leaks. Keep an eye on your coolant level. If if continues to drop and your overflow seems full could be a similar problem.