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.

 

[Zep5.0]

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.

Since you're likely needing more than 2 gallons, get one gallon coolant and 2 gallon distilled water.

 

[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.

 

[SnowyOwl]

Trying to drain the coolant on my 4.6. Is this the cylinder block plug? (Photo taken while facing forward, driver side, engine oil pan is there on the right) How the hell can I reach that plug? No normal tool would fit.



Anyone who would remember whether this is a 8 mm hex or which size?

I could only get about half of the coolant out from the radiator drain plug.

edit: thx to the staff for moving this post to a correct thread

 

[Kidd-7]

I’ve never used that, in the past I’ve ran a garden hose through the upper hose and flushed all the old coolant out. It’s not ideal, but has worked.

 

[Vicinity]

Wasn't there an approach to refill the system with distilled water and drive it? Then drain that, rinse and repeat a few times before adding the coolant?

This prestone concentrate works well, right? The labeling looks different then the last replacement. Im behind on exchanging the fluid, but finally getting some time off

https://www.oreillyauto.com/detail/c/prestone/prestone-1-gallon-yellow-concentrate-antifreeze-coolant/afzc/af2000

 

[SnowyOwl]

Wasn't there an approach to refill the system with distilled water and drive it? Then drain that, rinse and repeat a few times before adding the coolant?

This method sounds good as well.

I tried to fabricate a special tool from an L-shaped hex key, by cutting it from the red line:
But at least on my first attempt it was still too long to get properly seated.

 

[1997ThunderbirdLXV6]

Is there agreement on what coolant to use, other than conventional green, which is increasingly difficult to find?

 

[Kenz]

I have always used whatever is on sale. I thought they came from factory with the Motorcraft gold stuff

 

[1997ThunderbirdLXV6]

. I thought they came from factory with the Motorcraft gold stuff

I thought they came from the factory with conventional green (?). That's what my car came with from the previous owner.

 

[1997ThunderbirdLXV6]

Oh, and drain plug location(s) of engine block drain plug(s) on the 3.8?

 

[KevinVarnes]

I just use the green stuff. Still available around here. You could use the gold/yellow universal stuff as well.

 

[1997ThunderbirdLXV6]

Oh, and drain plug location(s) of engine block drain plug(s) on the 3.8?

Some Mustang info on this:

where is the engine coolant drain plug ?

I flushed the cooling system by draining the radiator plug and running water thru the system and all, but I couldn't find the engine coolant drain plug. The Haynes manual says that there are two such plugs on each both sides of the engine and is usually found an inch and half above the oil pan...

www.allfordmustangs.com

I just use the green stuff. Still available around here.

Here it's hit or miss. Walmart doesn't carry it. Autozone or Advance only carry it in some stores.


What's everyone's thought on using a "flush" before refilling with coolant? Are those useful or potentially too aggressive? Last time, I simply drained and refilled.

 

[CDsDontBurn]

Some Mustang info on this:

where is the engine coolant drain plug ?

I flushed the cooling system by draining the radiator plug and running water thru the system and all, but I couldn't find the engine coolant drain plug. The Haynes manual says that there are two such plugs on each both sides of the engine and is usually found an inch and half above the oil pan...

www.allfordmustangs.com

Here it's hit or miss. Walmart doesn't carry it. Autozone or Advance only carry it in some stores.


What's everyone's thought on using a "flush" before refilling with coolant? Are those useful or potentially too aggressive? Last time, I simply drained and refilled.

I'm a "drain and fill" type person.

 

[KevinVarnes]

What's everyone's thought on using a "flush" before refilling with coolant? Are those useful or potentially too aggressive? Last time, I simply drained and refilled.

Unless the coolant is nasty and/or hasn't been changed in a while, I would just do a drain and refill. I think you just did one not too long ago correct?

 

[1997ThunderbirdLXV6]

Unless the coolant is nasty and/or hasn't been changed in a while, I would just do a drain and refill. I think you just did one not too long ago correct?

About 15,000 miles ago.

 

[SnowyOwl]

I've drained and refilled mine twice now (with water), and the liquid is still brown after running the engine for a while. A proper flushing of all components in the loop would be the proper operation to do, but I don't really have the time for that now.. I'll probably give it one more drain and then refill with coolant. Hoping it's better than nothing. The old coolant was probably around 10 years old.

Is there agreement on what coolant to use, other than conventional green, which is increasingly difficult to find?

The Owner's Guide (at least for my 1994 T-Bird) states that the proper coolant is as Ford standard ESE-M97B44-A and ESE-M97B43-A. At least the first mentioned is green and seems to be even available as a Motorcraft item too. (Personally I'll be using some standard green from a local store instead)