i have a 2001 durango 4.7 it recently started overheating, no coolant in oil .. but it must be losing some coolant somewhere i just did a coolant flush about 4 weeks ago ... it started overheating today again .. i checked coolant and it was low...i filled it up and it still keeps on overheating now its outside running as we speak. there is some foam at the top of the coolant where you take the cap off and it keeps bubbling.. no sign of oil or nothing and whenever i take the cap off i hear lots of air and bubbling.... no coolant in oin and no oil in collant any ideas please help

 

the only time it seems to start doing the bubbling is when i turn the heat and fan off

 

You need to bleed out the air and fill to the appropriate level. Check your overflow for appropriate level more often because you most likely let it go dry and over heat and now you might have blown a head gasket. How hot did you let it go?

 

well it didnt get too hot i am kinda smart on cars, but only about average . i bought this durango for my wife as she always wanted one,anyway it was only about a quart low on coolant but i didnt let it get to the red line, as far as it got was the check gauges light came on then i shut it down and started to mess with it...now that we are home i have had time to mess with it. i let it run for awhile in the driveway.after it cools down, it dont make the bubbling or the foamy stuff at the top, and the coolant looks clean and green. after i drive it about 70 to 75 mph with the ac on is when it starts to get warm.. and if i bring it home and mess with the cap its got all kinds of bubbling and foaming.. if i let it sit running it cools off and temp gets normal ... i also spreyed out the radiator and got the bugs off it , but it still does it when i am driving it and making it work.. radiator is clean on outside ... i am worried as this is my wifes truck and we like it alot..

 

how much fluid was left in the reservoir at this point? that is what matters, if this ran empty you need to properly burp the system, if this didnt get low then you have a blockage in the system somewhere stopping the coolant from circulating properly

and the heat inside the truck is run off the same system, so heating the interior is like running another smaller radiator (heater core)and helps cool the engine

 

the overflow is always almost full .. i dont understand this problem,..when the durango is sitting it runs cool.. only when i am driving and i think only when the ac is on but could be wrong does it get hot, and also when i take the radiator cap off i can see the coolant flowing in there real good.. but it makes me wonder why the overflow is always full.. also there is like a big big spring in the radiator hose by the coolant cap is this normal ? could it be a thermostat ? when it gets hot there is all kinds of bubbling and things goiing on..

 

the spring is normal, its there to help prevent the hose from collapsing

if you only overheat when the A/C is on i would check the e-fan to make sure it is working properly, should be on with the A/C or when the engine gets over 210*F

 

If you can see the coolant flowing when you take off your cap, this is an indication that you have a stuck open thermostat. It makes me think this way also when you said that it runs cool when idling in the driveway but gets hotter when you start to drive it down the road. Sharp is right in telling you to make sure your E-fan is working when you also turn on the A/C.

 

I'm thinkin a T-stat or water pump.


Also what about a fan clutch? Have you tested it?

 

is it possable thaT i got a head gasket problem blowing exghaust into the coolant ? only doing it when the engine is working harder ?.. i did coolant flush about a month ago and it overheated sunday ,and for some reason it was low on coolant a bit ... i dont smell coolant and i dont see it leaking anywhere... also when we bought the durango coolant was full and about a month later it started to try and overheat again .. checked it and it was low again...it only seems to wanna do it when i am driving 70 mph plus... i dont get it.. i wish there was a easy way to test for this...