14 6.7L Coolant Flush - Ford Powerstroke Diesel Forum
General 6.7 Discussion (2011-2016) General 6.7 Discussion

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post #1 of 4 Old 09-19-2019, 10:28 AM Thread Starter
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14 6.7L Coolant Flush

Hey - Im looking to flush my coolant (primary only, no EGR) and so I am trying to gather some information on how it is done.
From what I have gathered on some posts here and other forums this is about how it works. Im trying to make sure i have the process down though.

1: drain whatever is in the primary system via block hose and pea**** drain
2: button up, fill distilled water in coolant tank/degas - aka reservoir - to MIN and fill rad tank.
3: run for 20ish minutes
4: drain distilled water in the same fashion as step 1
5: repeat X number of times until water is crystal clear
6: button up, fill with mixture of Ford OEM Orange AND distilled water. 50% orange, 50% distilled water
7: burp system(?) / ensure no air bubbles
7: Use a kit to test for that badbad.

The truck is at 83k but I bought it at 63k and it had an unknown background. The EGR fell off around 74k and the coolant was tested at that point. It came back good.
I expect to get some responses "why do you want to flush the coolant at 83k?" but i want to do it since i dont know very many details on the background of the vehicle and for my own peace of mind.
I called a shop to get a quote on what they would charge for it and they said $140. All my research says thats definitely just a typical drain and fill even though they tell me its not. The guy on the phone said "we drain it, fill it with a chemical bleach and cycle it with a pump, then we run distilled water through it and then fill it back up with coolant." Im not going to lie the posts ive found on here have scared me away from having someone else do this job.

Do i need the airlift vacuum system in order to do this at home? Do i need to cycle a chemical cleaning solution BEFORE i cycle in distilled water or no chemical solution at all - ive read mixed responses. Any feedback is helpful. Thanks
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post #2 of 4 Old 09-19-2019, 01:59 PM
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Interested as I have a 2012 that has an excellent maintenance record, however I want to flush the radiator and the trans just so I KNOW what is in there and HOW it was done.

I DO NOT trust a dealer to do it right.
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post #3 of 4 Old 09-19-2019, 03:30 PM
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To flush the transmission, you will need a machine that heats the fluid since the 6R140 has a thermostat. The thermostat prevents fluid from going to the radiator/cooler when not needed. You will need the fluid heated to open the thermostat.

It is easier to use a radiator vacuum fill device when filling the cooling system after a flush. You use air connected to the tool to pull a vacuum on the cooling system. Once you have a vacuum, you can disconnect the air source, get a bucket that will hold your 50/50 coolant. Drop the pickup tube form the vac fill device into bucket and opening the valve. Once the bucket of 50/50 gets low, close the valve and add more coolant to bucket and repeat. This is the method Ford recommends.

Yes, you can do the burp/fill process also.

You do not need to flush unless there was oil or other contaminants in the coolant. It is recommended to use purified water when mixing full strength coolant to achieve 50/50. Your owner's manual will tell you approx mixed coolant quantity needed to refill the system.

You can use any coolant, DexCool or similar that meets Fords requirements or the ASTM specs at this link

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post #4 of 4 Old 09-20-2019, 02:24 PM
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I know I didnt follow the manual perfectly. I know I didnt do as the videos on youtube outlined. I flushed my coolant systems (both) on my 2012 F-250 recently. Here's what I did.

Primary and secondary I basically did the exact same process except on the secondary I didnt use pet**** but instead disconnected the hose on the bottom of the cooler where there is a simple hose clamp.

1.Pulled the pet**** out from the bottom of the radiator. Drained.
2.Used my shop vac on blow to the top of the degas bottle to help get more out.
3.Filled with distilled water. Started the engine, topped off. Ran to 192F or so, ensuring the thermostat opened, topped of.
4.Repeated steps #1 #2 #3 probably 3-4x until it looked absolutely clear.
5.Used a refractometer and indeed it read 32F freezing point (straight water).
6.Repeat steps #1 #2 #3 and this time filled up with a higher concentration of coolant vs distilled. After ensuring operating temp and good mix I checked with refractometer. It showed -28F so I had to drain just a bit of coolant mix and add straight coolant (concentrate). I repeated and mixed and checked and i twas -36F. All done. This is about 50/50 mix based on the freeze temperature. There are refractometers for like $18 on Amazon. That is what I used ,they are really cool to have and eliminated the guessing work.

Removing the bolt from the engine or other methods I guess could have shortened this process but I didnt do it that way.
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