OK, I've got a '01 Durango 4.7L with 109k miles. About 2 weeks ago it started spraying anti-freeze out around the upper coolant hose. It didn't appear torn, but the hose on the block side of the cap was soft, so I decided to replace. Picked up a new assy. from NAPA, including the cap. Replaced, added some coolant, (about a qt. or so), and everything was back to normal. Yesterday I'm driving and I smell coolant inside the car, (no leaks inside, just the odor through the A/C vents). Anyway I stop and see anti freeze around the cap. Wipe it off, and try to tighten the cap, but it is either on or off near as I can tell. Anyway, I let it cool down a bit, restart, no leak, As I start to drive home, the temp gauge climbs. I throw on the heater, (fun on a 102 deg. day), and continue home. Temp comes down into the normal range for this car, (just below the half way point). Turn the heat off, it stays put. Put the air back on, no problem. Total trip home 8 miles, avg. about 35 mph. Anyway, I check the old cap vs the new, and the old is 21psi, the new was 20. Put the old cap on, started the truck and warmed it up, no issues. Wife takes it today, drives about 10 miles, no prob, drives 10 miles back home and overheats in the driveway. I have her pop the hood, and she sees steam and coolant coming out around the cap. I'm really looking for suggestions. Nothing else is leaking, and no puking from the overflow.

 

you need to burp the system

 

A smell from the a/c vent points me towards a failing or about to fail heater core..

Also, have you changed or flushed the system lately? if so did u burp it?

just my

here is a good thread on burping the system https://dodgeforum.com/forum/1st-gen...ng-system.html

 

Yeah and it gets worse, cause now I have to admit I'm a nitwit. I went back under the hood after the thing cooled down and pulled the radiator cap back off. I compared it to the other, and they were just a little bit different in the hooked tab area that slides up on the fitting. Looking at the original piece, (I never throw anything away until I know I don't need it), the water neck is also just a bit different. Anyway, when I slid the caps onto the new neck, I was getting it to "bite", but it wasn't sliding all the way up on the ramp. My guess is that when it heated up, it would let just enough pressure and coolant to escape that it caused the intermittent problem. Once I fixed this, it still overheated, but I went back, filled and burped the system, life is now good. Maybe someone else will read this and avoid the same mistake.

 

Glad to hear life is good now