QUESTION

Even after loads of parts swapping, replacing, and flushing, I'm curious when the last time the coolant was flushed/changed in your vehicle. I recently picked up a gas tank from a local radiator shop I had taken to get dipped and was talking to the tech about the patch process for the hole in the tank. He pointed to a radiator that was dismantled and completely blocked with crud. He stated that in a recent training seminar it was explained to the technicians that fresh coolant becomes chemically acidic and destructive within 60 hours. Dexcool doesn't; however, if it is not changed by the five year mark it will literally turn into sludge overnight. Therefore, it is advisable to flush and change conventional coolant every three years.

Also, if the ratio of water to coolant is too high, then the vehicle's heater will not produce much heat. My truck is currently running too high of a ratio of water to coolant, and this morning, when the outside temperature was 18ºF it was all my truck could do to get to 170º. I froze during my drive to work (and if you know of the issues I've had, my truck has been running hot for over three years).

 

yup, im starting to thank that i have a vacuum leak somewhere.

 

I ran some clr in mine and let it sit for 30 mins. I hooked up a garden hose to one end of the heater hose and disconnected the other. The water flowed totally free through the core with back pressure at all.

 

The system isn't terribly complicated. The hot water should be pushed off the water pump and returns into the inlet right next to the radiator hose. If there is air in the system anywhere then it should flow out or if there is a flow problem then the truck should over heat because it should impact the entire cooling system and not just the heater.

 

It can flow good and still be clogged, and the other factor is how much debris is in the box around the core. Pine needles, leaves, and anything else in general that can get through the cowl after years.

 

Our heater cores do tend to hold air that doesn't circulate out on its own, which is why we see so many reports of the sound of gurgling behind the glove box.

The heater is its own little system in parallel with the engine cooling system, so overheating is not necessarily to be expected if there's a flow problem in the heater circuit.

 

If my understanding of the system is correct then it shouldn't matter. If there is air in the core then it should be flushed out once the engine starts. At that time the t-stat is closed so with the exception of what is flowing through the bypass there is liquid flowing through the core and since the system is closed the air has to be pushed through the system and into the block.

 

Theoretically, that is correct. In actual practice, it just doesn't work that way. The heater core is, unfortunately, the highest point in the cooling system. Air trapped there, will tend to stay there...... the water just flowing around it, so to speak. Backflushing the heater core will supposedly fix that. (it has for me. Twice.) I went thru all sorts of machinations to get good heat. The ONLY way I have successfully convinced my heater to actually get hot..... was to back flush the system.

Hose next to thermostat housing is the outlet TO the heater core, hose going to the steel pipe that goes into the water pump is the return line FROM the heater core.

 

In theory you are correct, but when it concerns a dodge ram you are wrong! LOL

 

It clearly does matter, so there you have it.