I've seen this mentioned in other threads, the capacity it a bit over 4 gallons, when draining, only get 2 gallons. Filled with water, brought to temperature, ran heater... but only get 2 gallons.

Objective is to change out the fluid for new at service intervals. If I can't remove the old, then does that mean that a large% is still water??? And how do I get it all out??

4gal 50/50

2 gallons comes out

Fill with 2 gallons water

Now system is 75/25

Drain system for new coolant.

Put in 50/50 mix. Now whats in the system is not 50/50. Please help. I need to know how to drain all the fluid.

 

Some fluid is always going to be trapped in the system, unless there are drain plugs in the block..... This is where a flush machine comes in handy. Tad expensive for your typical home mechanic though.

 

Put the rear on ramps or face downhill, then drain it. If that ain't enough, just perform multiple drains. Coolant is cheap, especially Walmart Supertech concentrate mixed with distilled water.

 

Chyrsler spec is HOAT, I use the G05 Zertec - usually can get some discount on AdvanceAuto and knock the price of concentrated (makes 2 gallons) down to about $16. I've had quite a few chrysler products that when I have had to open the system up, I see no oxidation at all and its all looks brand new and clean inside. The 5.7 I recently bought had something green in it, and sure enough there was some oxidation on the inside of the pump... .YMMV.

 

Remember, your entire cooling system is the rad, overflow tank, hoses to and from the engine, engine cooling passages and everything associated with the HEATER CORE (alot of people forget that one). Between not being able to drain the engine fully and the heating system, you'll never be able to remove the full amount unless you have some crazy vacuum system.

 

I had good luck draining my cooling system by using a shop vac in blow mode.
Drain the radiator. Remove the thermostat and drain the radiator some more.
Remove the lower rad hose from the radiator. Blow air into the block at the thermostat hole.
Disconnect the two heater core hoses at the water pump. Drain the heater core.
Blow the rest of the heater core with the shop vac.

 

great idea...i'm betting you have swimming pool that you winterize...its what I use to drain the system...never thought to apply it to automotive.

 

You're correct about the pool prime, using same technique for car...