Draining and replacing coolant

[CDsDontBurn]

Next question on the MN12 platform, because it's been so long I don't remember

How much coolant will I need to get to fully top off the system? It seems I'll need 2gal of coolant but use only like 1-1/2gal or so. True?

This is to replace coolant lost in radiator, intake manifold, and water pump.

Follow up question to this....

Is there anywhere on the engine block itself that I can drain the coolant from to avoid making a mess? If so, where is said engine block coolant drain plug?

 

[Grog6]

unless you're in an extreme cold area, add 1 gallon of AF, then fill it up with distilled water. 2 gal distilled usually does it on an empty system. be sure to drain all the old coolant. engine plug is drivers' side, to the back, kinda under the manifold. radiator drain is pass side, toward bottom of rad.

 

[MadMikeyL]

If the system is completely empty, it may take a little more than 2 gallons. You can either get 3 gallons, or just dilute it a little, since you aren’t likely to experience extreme cold temperatures where you’re at. I’m not aware of any block drain on the 4.6, so just planning on a bunch dumping out when the water pump comes out.

 

[CDsDontBurn]

unless you're in an extreme cold area, add 1 gallon of AF, then fill it up with distilled water. 2 gal distilled usually does it on an empty system. be sure to drain all the old coolant. engine plug is drivers' side, to the back, kinda under the manifold. radiator drain is pass side, toward bottom of rad.

If the system is completely empty, it may take a little more than 2 gallons. You can either get 3 gallons, or just dilute it a little, since you aren’t likely to experience extreme cold temperatures where you’re at. I’m not aware of any block drain on the 4.6, so just planning on a bunch dumping out when the water pump comes out.

Sounds like I'm going to start with at least 2 gallons of coolant, lol. Not a big deal, just wanted to make sure of the amount.

My favorite is Prestone 50/50 premix stuff. Yeah, I know it's a bit more expensive, but it's just easier and less time consuming, so I'd rather pay that premium for less effort.

 

[1997ThunderbirdLXV6]

engine plug is drivers' side, to the back, kinda under the manifold.

I’m not aware of any block drain on the 4.6

Huh?

 

[XR7-4.6]

There are two block drains on the 4.6, one’s where I put my coolant gauge sensor in place of



The bank 1 one is behind the motor mount bracket(way to go engineers )

 

[Kenz]

Did the manifold and water pump on mine a few years ago. I just drained the system (slowly) through the radiator petcock the day before. I don't recall spilling much, if any coolant

 

[MadMikeyL]

There are two block drains on the 4.6, one’s where I put my coolant gauge sensor in place of

View attachment 13199

The bank 1 one is behind the motor mount bracket(way to go engineers )

That’s on the aluminum block. Are those there on the cast iron block too?

 

[XR7-4.6]

That’s on the aluminum block. Are those there on the cast iron block too?

Yep, roughly the same spots only they’re just below the rear most freeze plug on the driver side and the front most freeze plug on the passenger side

 

[CDsDontBurn]

Yep, roughly the same spots only they’re just below the rear most freeze plug on the driver side and the front most freeze plug on the passenger side

Do both need to be cracked open, or will just one be enough?

 

[XR7-4.6]

Do both need to be cracked open, or will just one be enough?

Both will get ALL of the old coolant out of the block ideally, but for the work involved in getting at the passenger side one, just the driver side one one will suffice to dilute the old coolant stuck in that bank IMO

 

[dDUBb]

What's the condition of the coolant currently ? .. I would imagine most would come out via the lower radiator hose and radiator drain .. pulling thr plug out of the block seems like a good way to take a coolant shower.

 

[XR7-4.6]

What's the condition of the coolant currently ? .. I would imagine most would come out via the lower radiator hose and radiator drain .. pulling thr plug out of the block seems like a good way to take a coolant shower.

The lower rad outlet is toward the top of the deck where the drains are right at the very bottom of the coolant galleys so there’s a good couple quarts to get out from the block drain(s).

I’m not particularly religious about it myself, when I change coolant I drain the rad from the petcock first and only drain the driver side because it’s easy and simply dilute what’s left in the passenger side and elsewhere with the new coolant every 3-4 years. It’s not really any messier than draining the oil, I’m always left relatively dry, though there’s always bound to be some splashback

 

[Grog6]

I do my coolant every 3 years. and I get all the old stuff out by using the block drains, removing the upper and lower hoses for inspecrion. I flush the block and radiator with my hose in the thermostat hole or upper hose hole.
I put everything back together, add i gallon of coolant, and 2 gallons of distilled water.
I can feel good in knowing all the hoses were checked for soft spots or other defect, and won't fail anytime soon.

 

[CDsDontBurn]

What's the condition of the coolant currently ? .. I would imagine most would come out via the lower radiator hose and radiator drain .. pulling thr plug out of the block seems like a good way to take a coolant shower.

I'm just trying to avoid a big mess of coolant when I pull the water pump.