I have a 2001 dakota 4.7l with 110,000 miles on it. I have not had any problems with it overheating in the past but a few months ago the durn thing overheated and I found it was low on coolant (it looked like it had been boiling over into the reserve tank and out the overflow). I decided to flush the entire system and it seemed to be okay for a few weeks and then it over heated again. It has now gotten to the point that it overheats often so I decided something more must be wrong. I can feel after driving the car that the top hose is alway burning hot yet the bottom hose is always cold and the radiator goes from hot on the intake side and cold to the outlet side. I started by replacing the thermostat. I pulled it out and put it in boiling water and it didn't open so i figured it was bad. The replacement I bought did in fact open right at 195 degrees in the hot water I put it in so I threw it. The car still overheated. Next I decided that the coolant still must not be flowing since the top hose was still hot and the bottom cold after driving and overheating so I replaced the water pump and the car still overheated with the same results. Today I just replaced the radiator thinking the old one may be clogged and inhibiting flow. I just got done installing it and the car still overheated. I am now out of ideas and have reached the extent of my knowledge on cooling systems. Any help on anything I may be missing would be greatly appreciated. I am starting to maybe wonder if there is a head gasket or cracked block issue
The only thing however, is that the coolant comes out nice and green and the oil still comes out nice and black. Not sure how great of an indicator that is for anything though.

One note is that I am having a hard time bleeding the system after I refill it with the coolant. I fill with coolant take a drive to get the car warm and loosen the bleeder screw, air seems to just keep spewing out to no end until all of the pressure in the system is gone. I have driven, bled, and then topped off coolant three times now with the heater running and the system still seems to have air in it.

 

**** bud it might be head gasket.. I just did mine on my 04 4.7 an they have cam over heads .. which is a lot more work .. I ended up taking mine to the shop.. found out I needed timing chains an sliders too .. I ended up having to get new heads .. so the 4.7 hates being over heated you might luck out an not need heads .. I got more then I expected when I got mine done 2800 was the total bill lol. That's if your problem is even head gaskets. Just alittle useless info for you

 

Make sure the thermostat is in correctly. It's very common to put it in "backwards." The coil part goes "inside."

 

Yeah I have pulled that and double checked it. I have it so the coils are facing into the block.

 

OK, so the thermostats in right.

Is the belt run the right way around the water pump? Maybe the impeller on the water pump is damaged.

You said the upper hose is hot. The bottom hose should be at least warm in that case. How's the output from the heater?

 

It pushes the system water out the reserve tank so much I wonder if your radiator cap is shot it has become so weak as to let it open very easy and pump water out.

If you have a new one it may be a cheap China carp one, use only stant its China also but still better.

I purchased a new cap last year that popped on so easy as to freak me out it took no effort at all to get on or off I returned it got a stant and that one was hard to get on and off like it should.

replace it and see what happens

 

I replaced the water pump last week and I am 100% sure the belt is around it correctly.

I am going to try a new radiator cap tomorrow and see what happens. Thanks for the help folks! I hate to say it but I am about the the point to have to take it in and fork over the money to have it gone through and fixed

 

also my heater runs constantly hot without any temperature fluctuations

 

If the new cap stops the overflowing problem and the air in the system problem then think on this if still showing as Hot change out the temp sensor you may be surprised to find out it’s not as hot as it shows you. My truck was showing close to being too Hot till I changed my temp sensor now it show as fine not too Hot.

So you may have two problems a bad rad cap and an overly sensitive or out of wack water temp sensor.

 

did you make sure you got the right water pump cause if you didn't they can turn both directions it's all in how the impeller is set up inside