Join Date: Feb 2016
Location: Lansing, Michigan
Ram Year: 2001 1500 Sport with 3/4 ton spring pack
Engine: Magnum 318
I'm not sure of the effects of Propylene Glycol on the internal gaskets and seals. The service manual calls for ethylene glycol. Personally I just get the Prestone concentrate, its greenish yellow, but it won't eat away at any of the gaskets that might not play well with Propylene Glycol. Low Toxic is pointless, unless you plan on drinking it, there is no need.
You can try putting it in there if that is your preferred brand, it shouldn't do anything negative. In the past using the wrong type of antifreeze could cause problems, but lots has changed since then. I just don't know what internal gaskets it might not play with.
As for the procedure, if you don't have a heater core leak, dont flush it with a hose, you might have a tiny leak that isn't noticeable that will get blown wide open. To flush the heater core, get a funnel and just pour water in the hose with the funnel.
For the rest of it, do as follows.
Remove the radiator cap.
On the bottom driver side of the radiator there is a drain petcock, turn it counterclockwise. It may be stuck, you can use a small pair of pliers and gently twist it back and forth until it breaks loose.
Use a pair or channel locks or vise grips to grab the hose clamp on the top side of the radiator and slide it back to clear the radiator. Use a twisting motion while pulling to get the hose off the radiator. It it doesnt want to come off, you can either cut the hose, or get a small flathead and shove it under the hose to break the seal. The same goes for the lower hose.
Getting the thermostat out is a bit tricky, but its possible to do without removing the alternator/AC compressor bracket, or either of the two components individually. You will have to remove the air filter box support arm that runs from near the alternator to the intake. You should be able to get to the two bolts that hold the thermostat housing on by using an extension or two. Once you get that unbolted and removed, not the direction the thermostat is facing, then remove it and clean off all the old gasket material and or RTV.
If you want to keep a bunch of water from flowing all over the top of the engine, you are going to have to put the thermostat housing and upper radiator hose back on the engine. If you don't care, just leave it off.
Using a garden hose (having a shutoff nozzle on the end makes it so much easier) spray water into the radiator from the top, once the water runs clear, spray it in the bottom until it runs clear from the top. (you may have to make a slight seal with your hand when reverse flushing from the bottom.
Once you flush the radiator, put the garden hose in the lower hose on the engine and spray until the water runs clear (don't bother with the heat settings, we don't have heater control valves). The spray water in the upper hose coming from the engine until it runs clear.
I do as follows, flush forwards, flush reverse, flush forwards. Then i'm done, anything more is just a waste of time.
To flush the heater core(necessary only if heat is poor). Pull the heater line by the water pump on the driver side, there is a constant tension hose clamp. On the passenger side near the valve cover the heater line has a junction, remove the hose closer to the back of the vehicle. Using a funnel, pour water into the heater core line on the passenger side until the water runs clear. Then do the same on the driver side heater line, then back to the passenger side and call it good. If you live in northern areas and are worried about the coolant freezing if the temps drop, you can either blow the remaining water from the heater core by mouth or low pressure air gun, or mix the coolant with slightly less water.
When putting the new thermostat in, make sure to put it in SPRING SIDE DOWN. Otherwise your engine will overheat. I personally buy a thermostat gasket then apply a light coat of RTV to both sides. The RTV helps seal as well as keep the gasket from sliding around. The order is Thermostat, Gasket, thermostat housing.
Once all the hoses are back on, you can fill the cooling system one of two ways. Put the concentrate in first, the fill with water, or mix outside of the vehicle then fill. Neither will cause harm, but if you use the vehicle to mix the coolant, make sure to let it run for a bit before temps drop to freezing to allow proper mixing.
You can lookup charts on the coolant mix for different temperatures, or just go 50/50.
When filling, fill the radiator most of the way, then start the engine. Fill as needed while it is warming up, the level will drop slowly until the thermostat opens. After the upper radiator hose is hot, top off the radiator and replace the radiator cap.
Now you're done.