Coolant drain and fill on the 6.4....?

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U&A

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So iv got the water and coolant set aside. My truck threw a code for a thermostat problem a while ago. It was stuck open so my temps have not broke 200 since.

Finally getting to swapping out the thermostat housing and obviously draining all the coolant and refilling. Was going to start today. Obviously our radiators don’t have the standard cap and we have to fill through the reservoir. Are there any tricks I need to know?

I planned on taking the thermostat out and letting drain out whatever it wants to as well as pulling the plug on the radiator.

What worries me is refilling the system only through the reservoir. Dose this work? I’m assuming I’m gonna get some air pockets that have to work their way out but I wanted to double check before I start going at it. All data tells me I need a special machine to fill the system. Is it necessary? Have others done a standard drain and fill yet?

2016
RAM 3500
6.4 Hemi
 

Hemi395

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I think it just takes longer to bleed the air out of the system, hopefully someone with a 6.4 can confirm
 
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U&A

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Thanks Hemi. Your probably right. Definitely interested if others have done it this way yet? Im sure by now
 

Rlaf75

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That "special" machine is a vacuum fill tool. It gets attached to the reservoir tank and you use compressed air to create a vacuum in the system. It sucks the air out of everything and you can watch the hoses contract indicating the air is gone. Once the vacuum is created, a hose is inserted into a bucket of antifreeze then the vacuum is released which draws the antifreeze into the entire system. Once it's full again you cap it off and you're good. That tool makes it very quick but you do not need it. Simply fill the tank and let it drain in. Continue filling the tank until it stays full. Cap it then start the vehicle. It's a little more time consuming but you should be good to go.
 

crazy jerry

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if your going to do it right. theres a nipple on the radiator drain valve to plug in a small hose and drain most all of it in a bucket without spilling anything. the tstat housing bolts should be torqed evenly upon assembly. system should be refilled with vacuum tool. doing it any other way ,may or may not have good results but thats your call
 
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U&A

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That "special" machine is a vacuum fill tool. It gets attached to the reservoir tank and you use compressed air to create a vacuum in the system. It sucks the air out of everything and you can watch the hoses contract indicating the air is gone. Once the vacuum is created, a hose is inserted into a bucket of antifreeze then the vacuum is released which draws the antifreeze into the entire system. Once it's full again you cap it off and you're good. That tool makes it very quick but you do not need it. Simply fill the tank and let it drain in. Continue filling the tank until it stays full. Cap it then start the vehicle. It's a little more time consuming but you should be good to go.
Appreciate it man. Thanks a lot
 

buckeyexx

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When I pulled my thermostat and replaced it on my 6.4 it was just a matter of filling the reservoir and starting the truck. Let the truck get up to temp which takes a little longer and let the thermostat open. Once that thermostat opens it will pull coolant from the resevoir to fill the system. I believe I shut the truck down a couple of times and each time it would pull coolant. Keep your cap off to allow air to escape while doing it and keep an eye on it for a couple of days and fill if needed.
 
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I needed a coolant change anyway.

I appreciate the posts guys. Got the first drain and fill done. Too dark out now so I’m gonna do more tomorrow after work.

New thermostat is in as well obviously
 
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U&A

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When I pulled my thermostat and replaced it on my 6.4 it was just a matter of filling the reservoir and starting the truck. Let the truck get up to temp which takes a little longer and let the thermostat open. Once that thermostat opens it will pull coolant from the resevoir to fill the system. I believe I shut the truck down a couple of times and each time it would pull coolant. Keep your cap off to allow air to escape while doing it and keep an eye on it for a couple of days and fill if needed.
Nice

Thanks man! Very helpful
 

buckeyexx

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Your welcome! I’m actually going to flush my entire system before winter so I need to do this all soon.
 
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mtofell

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I think it was this truck that I read guys had better luck pulling the front end up on ramps to get the air out of the system. I seem to remember some discussion of people having trouble but elevating the front helped.
 
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U&A

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I think it was this truck that I read guys had better luck pulling the front end up on ramps to get the air out of the system. I seem to remember some discussion of people having trouble but elevating the front helped.
Maybe that’s why I struggled to get all of the coolant out. because I had the front end lower than the back.:anitoof:I was thinking the reservoir on the passenger side should be the highest point guess I was wrong:33:

Ill move the truck and park the front up tonight. I was wondering that. Thanks a lot man:favorites13:
 

GsRAM

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I'm late to this party, but no vacuum machine is needed. I just did this on my truck this past fall. I had no issues. I pulled the lower radiator hose and drained all the old coolant into a large pan. Then I flushed the radiator and overflow tank with water, let it drain, reattached the lower radiator hose, then refilled and started thr truck with the cap off of the tank so air could easily escape.

It took some time running and a few check and top offs afterwards until all the air was out, but now all is well and has been for many months now.

Noone has mentioned it, but these trucks (at least my 2017 does) take OAT coolant. Its extremely important that you check your owners manual and use the specified coolant. Mixing different types can cause a host of issues. I ordered mopar coolant from Amazon.
 
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I'm late to this party, but no vacuum machine is needed. I just did this on my truck this past fall. I had no issues. I pulled the lower radiator hose and drained all the old coolant into a large pan. Then I flushed the radiator and overflow tank with water, let it drain, reattached the lower radiator hose, then refilled and started thr truck with the cap off of the tank so air could easily escape.

It took some time running and a few check and top offs afterwards until all the air was out, but now all is well and has been for many months now.

Noone has mentioned it, but these trucks (at least my 2017 does) take OAT coolant. Its extremely important that you check your owners manual and use the specified coolant. Mixing different types can cause a host of issues. I ordered mopar coolant from Amazon.
Yup

It went smoother than I expected.

And yes on the OAT

I also just put OAT in my bike too. Best stuff you can get IMO
 

GsRAM

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its neede if you want to be done in 15min and not top it off 27 times hoping the airs out
I topped mine off maybe 3 to 4 times total and the coolant level has been consistent ever since. There is no hoping all of the air is out. I understand the efficiency of the vaccum, but it's not needed to do the job.
 
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