Coolant system cleaners

[Jozef Zoldos]

Are coolant system cleaners needed when flushing coolant system? Are they bad for the gaskets in and around the system? Is it better to do a flush with distilled water until clean, drain the system and then replace new antifreeze?

 

[Soliyou]

Do you see any debris or rust in the system?? These new coolants are pretty good in keeping the system clean.

I even stopped doing flushes since I have difficulties getting all the distilled/tap water out and getting the correct coolant mix ratio.

Now I just drain and refill with new coolant couple of times and call it a day

 

[Jozef Zoldos]

Do you see any debris or rust in the system?? These new coolants are pretty good in keeping the system clean.

I even stopped doing flushes since I have difficulties getting all the distilled/tap water out and getting the correct coolant mix ratio.

Now I just drain and refill with new coolant couple of times and call it a day

Good point. Only a moderate amount of cloudiness. No rust. Because I am retired and have a ton of time on my hands, I decided to do it anyway becasue I was servicing everything else on my truck including brakejob, brake flush, differential fluids (front and rear), transfer case, transmission, etc. I did it on my 2020 expy with about 60,000 miles on the odometer. Below i will lay out how it went for anyone who decides to take on the task. I decided not to use any coolant cleaner becasue there was no rust and only a moderate amount of cloudiness.

Firstly, I decided to flust the system out thoroughly. Used only distilled water only. Hooked a small hose to the radiator stopcock on the driver side behind the bumper and opened up the valve. About 6 to 6.5 litres drained out with this method. Pretty easy and no mess doing it this way. Since the fluid capacity for the coolant system is 16 litres, there was only a partial drain of the entire system (~35-40%). I have a sweet vacuume fill setup and then filled system up with distilled water. Then you have to bring engine up to temp by driving with the heaters on in front and back to allow the system to let everything circulate through and equilibrate. By my calculations, to do a 95% flush of the entire coolant system you have to drain and fill with distilled water 6 times using this method which is what I did. The entire process used about 10 -11 gallons of distilled water. The first couple of drain/fill cycles revealed that the fluid that I removed was pretty cloudy and fine sediment would settle out.

Next, I added concentrated coolant to the system by draining the system out with the aforementioned radiator stopcock and filled with concentrated coolant. I did two bouts of this to get my system up to a reasonable concentration for freeze protection (~-30F). Checked final concentration with an antifreeze coolant tester. In total I used 3 gallons of concentrated yellow coolant.

This method is very complete and I am glad that I did it because of the sediment that settled out but I understand that it is probably a little overkill for many. But if you got time on your hands and want to do a complete flush, it is probably the way to go.

 

[GaryH]

By my calculations, to do a 95% flush of the entire coolant system you have to drain and fill with distilled water 6 times using this method which is what I did. The entire process used about 10 -11 gallons of distilled water. The first couple of drain/fill cycles revealed that the fluid that I removed was pretty cloudy and fine sediment would settle out.

Next, I added concentrated coolant to the system by draining the system out with the aforementioned radiator stopcock and filled with concentrated coolant. I did two bouts of this to get my system up to a reasonable concentration for freeze protection (~-30F). Checked final concentration with an antifreeze coolant tester. In total I used 3 gallons of concentrated yellow coolant.

This method is very complete and I am glad that I did it because of the sediment that settled out but I understand that it is probably a little overkill for many. But if you got time on your hands and want to do a complete flush, it is probably the way to go.

Pretty much how I did it on my '03 with 5.4 engine. Used 10 gallons of distilled water to drain and fill 5 times. After the last drain, I put in two gallons of concentrated coolant and topped it off with distilled water. Coolant meter shows a 50/50 mixture. Good enough for our Central Texas climate.

 

[VBreithaupt]

How long do you guys run it?, with heaters on etc. between flushes ? Can you elaborate on vacuum fill setup and do you need it. Thanks

 

[Jozef Zoldos]

How long do you guys run it?, with heaters on etc. between flushes ? Can you elaborate on vacuum fill setup and do you need it. Thanks

I ran it with the heaters on in the front and back until it was up to temp so that the thermostat would open. About 5 minutes on the highway would ususally do the trick. This would allow everything to circulate and mix well in all areas where the coolant runs.

As far as the vacuum filling, here is a youtube video for this.... https://youtu.be/_WCRcuCZI50?si=kO6FQLMdz-DYnQow. I have a vacuum filling setup that I use with different adapters for different manufacturers but you can probably get a rent-a-tool from one of your local auto part shops for this.