I was told to check the air bypass valve but can't find it. I was also told to check the coils under my dash but I don't know if that will be easy lol. This is on a 2k dakota 3.9. My radiator and thermostat have been replaced in the 2 months so I don't think its a coolant issue.

 

I bet that if you felt the hoses going to the heater core you will find that one will be alot colder than the other. I know we have seen a few Dakotas and Durangos at the dealership that have the same problem and usually backflushing the heater core will take care of the problem.

 

wear more clothes....

lol sorry thats my fix, i'd agree with the above statement

 

I've been having the same problem so I took it in yesterday to have the cooling system pressure flushed. They advised me to diagnose it before wasting my money. They told me that both heater core hoses were the same temperature but, that my upper radiator hose was 153F and the lower was only 81F. They were able to detect that the thermostat was working so their diagnosis was the water pump. They wanted too much to change it so I went to NAPA and picked up a new pump, hoses, and thermostat for $150.

The problem is that when I got home tonight to start on it, I took a closer look at the pump from under the truck and see where coolant has started to seep from where the timing chain cover and the block meet. I would suggest that you take a look at this area first...I now have to go and get the gaskets to do this fix. Not looking forward to this!

 

All the above is good stuff. I'd check the waterpump as mentioned by looking for a leak and listen for the tell tale noises they make when going. The heater cores do have a tendancy to plug up over time so if no leaks are detected and there is no noticable loss of coolant noted, I'd flush it. The gunk may be restricting the heat exchange capablities of the core or even blocking the flow completly. Hopefully its just plugged up as the flush is cheapest of the lot. There are even do it yourself kits available, if your able to change your oil you should be able to handle the coolant flush and change.

 

I'm not sure if there is supposed to be coolant inside the timing chain cover....
I'd be willing to bet the coolant your seeing there is leaking out of the bottom of the water pump and blowing back on the block and timing chain cover and dripping down....the only gasket you'll need is the water pump and that may just be the correct permatek sealant if I remember right.
The fun part was getting the fan off the front of the water pump....

 

that's why you need an electric fan! haha.

 

Thanks for that info! I know some engines I have worked on have water jackets that run thru the timing chain cover and into the block but, I have not torn into this engine yet. Have you had your water pump off? Do you remember seeing any jackets or was it just a cavity?

Also, since you brought it up...LOL...getting the fan off. Any tips to make this easier??

Thanks!

 

i believe its just a cavity with 2 ports.

 

i just changed my pump saterday it was leaking coolant when the pump is off there are 2 cavitys for the coolant good luck with that metal pipe that connects on the driver side top i had to heat it up to get it out what a pain in the a$$$