Hello,
I just joined this group.
I also just purchased a:2001 Dodge Durango Sport - 4x4 - 4.7l - 157,000 miles
I have been reading all the troubleshooting info related to my vehicles problems. I have found answers to Some of my questions and was able to fix my rig according to the post feedbacks. Thank You All for this Helpful & Free info!!
I have one issue I need some help with. I have not been able to get a clear answer from the other threads I have read on here, about my vehicles issue.

I have a Percolator/Coffee Pot sound coming from behind the dash, towards the passenger side.

*Here are all the scenarios that seem to cause this noise...

1) the Defrost is On and the Fan is On - Engine is Running
2) the Defrost/Feet is On and the Fan is On - Engine is Running
3) the A/C is On and the Fan is On - Engine is Running (the A/C button also is pushed On)
4) the A/c MAX is On and the Fan is On - Engine is Running (the A/C button also is pushed On)
(no noise when the A/C button is Not On)

**Here are the scenarios when the Noise is Gone...

1) The Selector **** is in Any of the "Other positions" that I did NOT describe above - the Fan is On - Engine is Running
2) the Selector **** is in "ANY" of the Positions -Ignition Key is turned On - Fan is On - Engine "NOT" Running

*** A/C is currently: Blowing Warm

 

is your is your AC accumulator Frozen? does it leak a bunch of water after you shut it off?

 

I do not know what the AC Accumulator is so I don't know if it is frozen. I have checked several times, my Carpet up under the dash area is always Dry.
I get a slight coolant smell just after I start it up Cold, and the defrost of vent on with the fan on but, that slight smell only lasts maybe a minute or less.
I am trying to figure this out so I can fix it on my own and save $$ plus, I enjoy doing all my own work on my vehicles.
Someone on this site mentioned in another thread that, the slight smell could the heater core with a very small hole in the upper area that gives off a venting smell then stops venting? Something like that anyway.

 

Could be. I used to get that sound in my pt cruiser right after id drive it and turn off the engine with the same smell. Ha. I just realized. Same problem maybe? The sound sounded like water boiling in an enclosed area. Turned out to be my radiator fan wasnt.working and it would make my coolant boil into my radiator overflow and it would overflow out while boiling getting the smell. Mine was a combo of no radiator fan and a plugged radiator. You could maybe try a new radiator cap or thermostat, both under 10 bucks. Thats about the extent of my knowledge.

 

and if and if it is that when you run the AC it makes it boil super fast

 

I replaced the radiator cap - no change - Actually, after I put a New Radiator cap on, the engine temp Needle moved a couple needle widths to the warmer side BUT, the needle is still to the left of Top Dead Center/Middle of the Heat Gauge.
I appreciate your help!! I don't think what you are saying would be the issue though or else WHY does it only make the noise when the Controls are in certain positions and the fan ON.
Fan Off = No Noise
Fan must be on for all scenarios YET it is Not a Fan Type noise.
I have read on this site that it May be because the A/C is not charged/Blowing Warm.

 

if the a/c is blowing warm it does raise the question of how much refrigerant is in the system, probably wouldnt hurt to have it charged up and see if the noise goes away.

since it only happens with the a/c on i was thinking it could be a clogged drain for the a/c but since you said no cold air and no water on the floor that isnt the place to start.

my first thought was LOW coolant as in an air pocket stuck in the heater core even tho its related to the a/c is your coolant overflow full? is the top hose under the cap full?

 

The sound also happens in the Defrost mode. (either Defrost or A/C position)
I did the radiator cap off, idle engine to bleed air out of the system trick, that did not change anything. the Radiator Cap is the Highest Point on the engine cooling system.
The Fan must be on for this noise to start, it does Not make the noise in the vent or floor positions with the Fan On, either.
I will eventually have the A/C serviced but, it is Fall now and I don't really need A/C until next May or later.
I would be very surprised that it would be Low A/C coolant as the reason for this sound.
I tried to give Every Scenario in my Original Post so that maybe "Someone" has had this Exact issue before and found a fix for it. .
Thank You both for all your help so far!!

 

the a/c runs in defrost mode to dry out the air being blown on the windshield.

also if the hvac fan in the cabin is off the a/c clutch disengages

at this point since you have checked everything else it all points back to something with the a/c IMO

 

I am going to Try to find an A/C Specialist here in my area (Portland OR) and see if they will Troubleshoot this issue for Free. I called a well known Radiator & A/C specialist here but, the guy wanted me to leave my rig with them so they could troubleshoot it... I am not willing to pay these company's big $$ just so they can try to find the problem, I have done this many times in the past on numerous troubleshooting situations and more often than not, they say they fix something, I pay them, then on way home the problem is Still There. I have found I am the best mechanic I know, I get the job done Correctly, the first time. In my case right now though... I have not found out exactly what the problem is yet.
I may give in and have the A/C serviced with new Refrigerant and see if anything changes, at the very least I ought to have Cold A/C... I would think. lol
Thank You Sir!!