Would removing the t-stat and disconnecting each end of the radiator hoses and flushing water through the engine block and radiator with a garden hose get all of the old coolant out?

 

Sure if you turn the heater on too to get that fluid out.

 

You can always disconnect the upper radiator hose and dump out a quart or two of coolant and put in some of the coolant flush products they make. You can run that through the system for 10 minutes or a few days, then drain the radiator and such in order to get it all out. Then refill with coolant and distilled water.

 

By draining from the radiator plug and the engine block plug, does that get everything out, or would you still need the pressure from the hose through one of the radiator hoses?

 

I'm not sure that you need to be that exhaustive with the "flush". If you run the engine up to temp and then open the radiator pet****, the coolant will drain out and the thermostat will still be open (caution: coolant will be HOT). So it should drain out most of the coolant. It's not necessary to force pressurized water through the system.

 

So you mean run the engine with the radiator drain plug open until nothing comes out? Is it safe to have the coolant reservoir open at that time and to be pouring distilled water through the system as it drains? That way you could stop when you see clear water leaving out the radiator drain plug. Would it be safe to then wait until nothing comes out with the engine still running so you know everything has left the system, or would it overheat or something?

 

You don't need to run the engine. Just let it drain out of the radiator and pull the upper/lower hoses from the radiator to make sure it all drains out. Why do you think you need to flush regular water through the system?

 

It's my understanding that the coolant is not just in the radiator but in the engine block as well.

I saw this experienced mechanic use a garden hose to flush the cooling system, both the radiator and engine block:
Your further comments are appreciated if you're knowledgeable on this.

 

That is correct that there is coolant in the block as well as the radiator, however if you are pulling the lower radiator hose off, it will drain most of what is in the block as well. You can run water through it if you like, I just think it's somewhat pointless unless you have a ton of junk that somehow got into the cooling system.

 

When I flush mine, about every 2 years, I pull block plugs and radiator drain. I start the truck and let the water hose run into the overflow bottle. It does a pretty good job.

 

Don't drain coolant from a hot engine. There are a lot of different opinions on how to flush, or if one should flush. Here's how I do it.

Starting with a cold engine, remove radiator cap and radiator drain plug. Once drained, remove the heater hose from the intake and pump water into the engine. It won't take long before the water is flowing through the top of the radiator. Once the water is clear, start the engine for about 30 seconds while continuing to pump water through the heater hose. Shut the engine off, pump water until it comes out clear again, and repeat two or three times. Allow to drain and try not to minimize the water getting on the ignition coils in the process.

Here's the often-overlooked part. Now there is a fair amount of plain water hiding inside the heater core, block, and other areas. It adds up. So if you were to add a 50/50 mixture of coolant and water, it would be overly diluted.

The correct way to add after flushing is to divide the cooling system capacity in half and pour that amount of full-strength coolant into the system. So if you have the 4.6L, the cooling system capacity is 19.8 quarts (round it to 5 gallons). That means you must add 2.5 gallons of full-strength, then top off with water. Distilled water ideally.

If you measure how much coolant and water is added during the process, you may be surprised when you do the math of how much water was trapped inside.

If you opt to do the simple drain and fill, it's better than nothing. But before dumping in $40-$50 worth of coolant, might as well flush it out.

 

Depending on the hardness of the water in your area, it may not be a good idea to flush with tap water. The hardness plates out on the cooling system when it gets hot. I had to replace a heater core one time for that reason. I personally do not put tap water in my engines, only distilled water and antifreeze.

 

Drained/flushed radiator and engine block but could only refill two gallons of a five gallon system after running to temp. What gives?

Going to try draining the radiator plug after running to see what color comes out now. Once clear I will replace with as much pure coolant necessary for 50/50. Your advice is appreciated.

 

Assuming you actually flushed the system as I had outlined, I forgot to mention that the heater hose needs to be disconnected from the intake during the initial fill to eliminated most of the air from the cooling system.

 

Job done. To achieve 50/50 mix, drained the radiator plug of crystal clear distilled water, leaving me with about 2.5 gallons of coolant to add to the system. It holds 5 gallons so that's how I know it's 50/50. Thanks to everybody for your good help!