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I am doing a coolant flush and change on my 5.7 hemi. The car is over 10 years old and a little over 80,000 on the odometer. I am not sure if the previous owner ever had the coolant changed or not, so I figured it couldn't hurt to go ahead and flush, refill with new coolant, and replace the thermostat while I'm at it.

I have done my research on how to do this flush and properly switch in new coolant, but was surprised to see that when I fully drained the radiator (even with the rear end jacked up), I could only drain a mere 6 quarts (this thing holds 14.7 quarts total). I am aware that the remainder of this amount (8.7 quarts) is left in the engine block. If I do this flush according to what others have said, after cycling through my radiator flush product, and then repeatedly filling with water and flushing, the coolant should run clear and this indicates I have flushed any remaining coolant or debris out of the system.

This being said, my engine block will still be full of 8.7 quarts of distilled water, meaning the maximum water/coolant ratio I could get is around 40/60 (6 quarts coolant to 8.7 quarts water).

So, is this an OK mixture to run? Should I be draining what I can from the engine block, or is this a difficult process? Maybe there are some tricks to where I could drain more from just the radiator drain tube? Any help would be appreciated.
 

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The few times I messed with the coolant myself I disconnected a hose at the block which drained the block of coolant. (I vaguely recall one car has a coolant drain valve on the block.)

I never bothered to check how much coolant drained though but upon refilling by the amount of fluid I had to add it was pretty clear the bulk of the fluid had been drained from the cooling system.

Then when I got cars that required a vacuum lift system to properly fill the system -- with 2 or in one case 3 radiators and about a mile of hoses -- I just let this get done at the dealer. The price was reasonable and I didn't have to deal with the mess of draining the system and then making sure it was full with no air pockets after I refilled the system. And I wasn't stuck with gallons of old coolant to dispose of.

If you find you can't drain the system entirely then you will I guess have to flush with distilled water and run the engine to the point the T-stat opens and drain and repeat this until the drained water runs clear then allow for how much of this water remains in the system as you then mix antifreeze with distilled water.

If I were you I'd be seriously tempted to just fill with water and take the car to a shop to have the system flushed -- maybe after 10 years and 80K miles the shop will use some flushing additive -- then have the system refilled with a fresh mix of anti-freeze/distilled water.
 

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There are block drain plugs on each side of the V-block

they are hex head bolts - they are about inline where between where engine mount attaches to the block and you'll see the engine knock sensor (has a wire and metal heat shield)

removing those - do one side at a time. You'll want a fairly wide pan as its going to splash out a bit towards the end.
-when reinstalling them, you'll want to apply a thread sealant on the bolts

I got 3+ gallons of coolant out of mine - I was removing the heads (cam swap) and wanted all the coolant out of the block.

the water pump is up fairly high on the Hemis - so the lower hose is still fairly high up on the block. So the water jackets in the block still have coolant in them even if you remove the lower radiator hose.
 
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Drive it around town then drain and refill the radiator again. At that point you will be fine. Drain, flush, and refill your radiator every 5 years and you will never have an issue.
 

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that method will require probably 2 drain / flush cycles to get the old coolant out - and there's still remaining (now diluted) mixture in the block.

trying to get all of that to a 50:50 ratio would be tough since there's still 1/3 of the overall capacity of the system in the block
 

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Sometimes you just roll with ‘it’s way better than what it was’. Personally I’d just do the 2 drain/flush cycles and revisit it in 5 years.
 

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There are block drain plugs on each side of the V-block

they are hex head bolts - they are about inline where between where engine mount attaches to the block and you'll see the engine knock sensor (has a wire and metal heat shield)

removing those - do one side at a time. You'll want a fairly wide pan as its going to splash out a bit towards the end.
-when reinstalling them, you'll want to apply a thread sealant on the bolts

I got 3+ gallons of coolant out of mine - I was removing the heads (cam swap) and wanted all the coolant out of the block.

the water pump is up fairly high on the Hemis - so the lower hose is still fairly high up on the block. So the water jackets in the block still have coolant in them even if you remove the lower radiator hose.
Some -- well, at least one -- of my car engines had a drain plug in the block to drain all the coolant. If the Dodge engines have one or two of these that's great. No need then to remove the hose at the block. Unless the radiator has a drain plug though probably still have to remove a (lower) hose at the radiator.
 

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Yep, there is a drain plug each side of the 5.7 block - and removing them and draining the coolant means the block is pretty empty of coolant - certainly less ran out when I inverted the engine on the stand than has run out of much smaller 4 cylinder engines I've done the same to.
 

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Some -- well, at least one -- of my car engines had a drain plug in the block to drain all the coolant. If the Dodge engines have one or two of these that's great. No need then to remove the hose at the block. Unless the radiator has a drain plug though probably still have to remove a (lower) hose at the radiator.
there's a petcock on the bottom of the radiator - there's some residual coolant in the lower hose in the horizontal section that doesn't drain out completely.

accessing the clamps on the lower hose is tight - I have a tool that is a hose clamp plier that's cable operated.

Trying to R&R the clamps with a regular set of pliers - is not fun...
 

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there's a petcock on the bottom of the radiator - there's some residual coolant in the lower hose in the horizontal section that doesn't drain out completely.

accessing the clamps on the lower hose is tight - I have a tool that is a hose clamp plier that's cable operated.

Trying to R&R the clamps with a regular set of pliers - is not fun...
Water pump pliers (channel lock pliers?) work pretty well most times for the OEM style clips. Seen those cable operated pliers and nearly been tempted . . .

I really wondered if the drain **** was going to simply shear off when I tried it - it did not want to move. I guess it hadn't been moved since installation. Pulling on it at the same time as rocking/turning it got it out.

Reasonably impressed by the inclusion of a drain hose on it
 
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