It was very, very cold tonight when I got off work, about 3 below.

For those who haven't followed my other posts, I recently had a water pump go out and tried to save some cash by dumping some stop leak in the radiator. (yes, I know that was dumb. I knew it was dumb when I did it, but was hoping and praying to save some cash since I was out of work for a while).

Anyway, the stop leak experiment bit me in the *** a couple ways. First off, it didn't stop the leak, I was still spending more on antifreeze than I was on gas. (why can't these things happen in the summer when I could get by for a week with water from the garden hose? nope, only happens in the winter...) Secondly, as I knew it probably would, it clogged up my heater core, which made for some really cold drives home from work....

As I'm currently living in a crappy rental house with no heated garage, I opted to pay a local mechanic to swap out the water pump. Also asked him to flush the cooling system to get the stop leak out, with special attention to the heater core. This was a face to face conversation, so I know he understood me, and I also know the guy personally and know he does good work. And I'm a picky S.O.B. If I say somebody does good work, that means they're pretty much the best of the best. When I picked the truck up he told me that if the heat got weak again to bring it back and he'd flush the core one more time for free.

Well, a week and a half later, the heat is weak (well, weak for this truck. still better than the heat in any other vehicle I've ever owned). Thing is, I'm not sure if I want to use up my free flush just yet. Truck runs great, aside from pulling to the right too much, which I'll get fixed as soon as I can put new tires on.

Before the repairs there were a couple of times when it got pretty good and hot. Not full blown overheated, but to the point where the temp gauge was approaching the red and the vents were blowing air at outside temperature.

My concern is that the overheating probably whacked out my thermostat (and probably the radiator cap). So far everything is perfect until the temps get below about 10 degrees, at that point she just doesn't warm up the way she normally does.

I'm thinking I need to replace the thermostat, and throw in a new radiator cap just to be safe.

Anything else I should look at? I think I've got this one under control, just thought I'd throw it out there to see if anyone had some additional ideas.....

 

I feel ur pain, mine was a simple backflush, but until my garage could get me in, i had to drive to work looking like the staypuff marshmellow man...lol.

 

hey fellas im new to the durango world and my question will relate here. i have a 99 4x4 with a 318. i have a new water pump, radiator,thermostat, and cap, but i can only build heat up to about 170 ish. heat is ok but not like i think it should be. could i be air locked or do i need a back flush?

 

try a backflush, that usually works, but overtime the fins on the heater core can get clogged with debris, mold and such.

 

First thing to look at would be the actual temperature at the T-stat and not rely on just the instrument cluster read out.

Second thing, get the truck cold. Turn the heater on to high and hot level and start the truck. Open the radiator cap. Pour your anti-freeze in and gently press the throttle there under the hood on the Throttle Body to increase your RPM's to about 2000. You will watch the coolant fall and while you hold the throttle open top the radiator off and replace the cap. Fill your reservoir to the full mark on the dipstick consitering yours is a 1999.

Now if everything checks out then flush your heater core with a garden hose and house pressure and reassemble.

 

ok ill give all that a try how hard is it to pull the heater core out? gauge says around 170 but the hand on the top hose says hotter than that. can i use an ir temp gauge to get the t-stat temp accuratley or should i use a mechanical gauge?

 

you can use an ir thermometer to check what the actual temp is