Coolant flush techniques

[rattle_snake]

In process of a coolant flush/refill and wondering if it is possible/worth the effort to get 100% of the rust out.
I drained system by removing the lower-radiator-to-thermostat-housing hose and crossover-to-thermostat-housing hose (I get 2 gallons out this way). I left the lower-radiator-to-thermostat-housing hose off and added garden hose (soft) water to the crossover bung. Ran engine for 15min, although water was clear after 5 min. Drained, added 2 gallon distilled, got up to temp with a 5 mile drive, let cool for 5hrs, drained and check water. The water in the radiator is mostly clear, but the water in the block still has some rust. I repeated this cycle 4 times with 8 gallons of distilled.

So, do I:
1) Stop worrying and add antifreeze (Ford gold). It would be way better than it was.
2) Start over and flush again with garden hose
3) ?

 

[P49Y-CY]

i would say, "3) ", but only because i am similarly anal about keeping my cooling system well maintained. my annual process occurs over a period of about 2 weeks of driving where i get it to a point of 99% water (i don't use a/c during process).

i would say you are on the right track, but i think you will get more if you drive and then drain instead of running a hose while running the engine.

if you drain at the driver's side block, you will get more out of the block. a petcock installed in the bypass hose just before the t-stat and in the d/s block makes the process a little easier. also remove and try to clean out the reservoir (or buy a new one) because a lot of gunk winds up there. use a chemical flush before using distilled water until 99%, then add 2 gallons coolant for your final 50/50 mix.

the iron block does create more rust in the system but it is manageable if you maintain it frequently. best of luck!

 

[rattle_snake]

... i think you will get more if you drive and then drain instead of running a hose while running the engine.

I have done 4 drive/drain cycles. I capture some of the water in a clear container and after it sits for awhile and dumped out there is a residue left behind. Given the configuration of the cooling system (bypass style) I am on the diminishing return part of the exponential curve.

How much water will I get out of the driver side block drain? Is the plug at the rear of the block as shown in step #21 here?
https://www.svtperformance.com/foru...speedhut-gauges-and-sos-pod-with-pics.548499/

 

[P49Y-CY]

yeah that's it - only about half a gallon.

as i recall, this is how mine approximately breaks down (i haven't measured for a long time tho) :

1.5 gallons - t-stat
1 gallon - radiator (at petcock)
.5 gallon - drivers side block

so i am guessing that the passenger side would be about another half gallon, and the heater core would be another half gallon. never got that zealous as to drain either of those. but i plan to someday lol.

sorry i didn't originally see that you do drive 5 miles. as long as that is enough to open the t-stat fully and get it all mixed, yes i agree you should be good and there is not too much more you can do using this method. if you do it regularly, over the years you will see very little rust and residue in your system.

 

[Rambro]

What are you guys doing as far as disposing of the flushed coolant? just let it go down the drain?

 

[RichM1983]

I tackled this last spring. I flushed and flushed and my coolant still has rust. My advice is fill it with water and burp properly and drive it for a good long drive, at least 5-10 miles to get it all circulated. Do it several times. I didn't do it enough times and when I finally did the proper coolant mixture after the first long drive it was cloudy again. I did it 3 times.

 

[hotcobra03]

Was just thinking of this on ride to work today..I just did a new radiator awhile back and have just started getting a leak on degas tank..

Went to add coolant and noticed gunk inside..

I had ran a hose into mine and ran for awhile as it ran out ..

I'm thinking it would work better with slightly pressured hot water ...than cold from garden hose. ..

 

[RichM1983]

Was just thinking of this on ride to work today..I just did a new radiator awhile back and have just started getting a leak on degas tank..

Went to add coolant and noticed gunk inside..

I had ran a hose into mine and ran for awhile as it ran out ..

I'm thinking it would work better with slightly pressured hot water ...than cold from garden hose. ..

That reminds me of something. The expansion tank is basically impossible to clean. Mine had what appeared to be cracks in it. I replaced it. Still cloudy lol.

 

[P49Y-CY]

even though a lot of guys don't like it as far as under hood looks go, i like the completely clear reservoirs that they put on the '15-up mustangs. i think the dodge challenger and other manufacturers use them too.

with those i think you can see the condition of your coolant easier than with ours that have a black top.

 

[MalcolmV8]

What are you guys doing as far as disposing of the flushed coolant? just let it go down the drain?

No don't do that. Hazardous and goes into our drinking water. I bottle it up in old coolant bottles and take to a local jiffy lube or similar and dump in their coolant recycle tanks. It's free and doesn't cost you but a few minutes.

 

[MG0h3]

Also animals are attracted to it because it is sweet. doesnt take much to kill them so keep it covered if you have a dog in the family.