How Do YOU Flush Your System?

[Propflux01]

The Elantra is getting close to the 100K service/End of warranty/PM for the next 50K maintenance stage. I plan on doing a radiator/coolant flush and replacement. In te old days, we ran down to Wal-mart, got one of those flush kits that installed in the heater line and came with its little jug of flush magic. You used a garden hose till clear, then drained the water and refilled with your favourite brand of green coolant.

That was yesteryear, of course.

So how do You do your flushes in today's age of multi-coolant, multi-setup vehicles? I already know which type of coolant to use, but how does everyone go about doing the flush?

 

[FCD]

Unless the cooling system has been neglected ( rust in the system ) or you are switching to a different coolant type , doing a flush is simply unnecessary, just do a drain and fill.

 

[TheLawnRanger]

Snagglefoot posted the best way e few weeks ago. The post is called Removing Old Antifreeze by Dilution.

 

[slacktide_bitog]

I drain the radiator from the petcock. If I can't get it off, or if the radiator doesn't have one in the first place, I undo the lower radiator hose. To refill, I use the Lisle funnel

If it has been that neglected and rusty, the car usually needs a new radiator anyway at that point.

 

[Andy636]

Easy...I don't. Just change it and you are good for another 5 years.

 

[Warstud]

Since you have a newish vehicle and assuming the cooling system is in good condition I would just drain & fill and run it a week and repeat. Your system takes 6-1/4 quarts. Most of which is in the radiator.

 

[billt460]

Originally Posted by Propflux01
You used a garden hose till clear, then drained the water and refilled with your favourite brand of green coolant.

Do not use a garden hose. City pressure is anywhere between 45 to 65 PSI depending on your location. Most coolant systems are designed to operate at between 11 to 16 PSI. You can easily over pressurize your cooling system, and possibly damage it. I knew a neighbor that blew one of the side tanks off his heater core, (plastic and Aluminum core), and flooded his interior using a hose with a flushing tee.

Instead, just drain the system, then refill it with water, turn the heater control to high, then run the engine until the thermostat opens. Then drain, refill, and repeat until the water comes out clear. Then drain and refill with a 50/50 mix of whatever coolant you are going to use, and distilled water. It's a bit more time consuming that way. But it's easy, and you won't risk damaging anything.

 

[doitmyself]

Somebody explain to me how the Lisle funnel aids in filling the radiator and avoid air pockets. Thankyou.

 

[Warstud]

Originally Posted by billt460
Instead, just drain the system, then refill it with water, turn the heater control to high, then run the engine until the thermostat opens. Then drain, refill, and repeat until the water comes out clear. Then drain and refill with a 50/50 mix of whatever coolant you are going to use, and distilled water. It's a bit more time consuming that way. But it's easy, and you won't risk damaging anything.


If you flush with water and drain and fill with 50/50 AF what ratio do you end up with?

 

[demarpaint]

Assuming there isn't a mechanical problem that warrants flushing the cooling system, I don't let the cooling system go long enough to need a flush. I drain the radiator and recovery tank and replace the contents with the proper coolant/distilled water mix and call it done. That method has served me well.

 

[JC1]

Originally Posted by billt460

Instead, just drain the system, then refill it with water, turn the heater control to high, then run the engine until the thermostat opens. Then drain, refill, and repeat until the water comes out clear. Then drain and refill with a 50/50 mix of whatever coolant you are going to use, and distilled water. It's a bit more time consuming that way. But it's easy, and you won't risk damaging anything.


+1, this is what I do.

 

[slacktide_bitog]

Originally Posted by doitmyself
Somebody explain to me how the Lisle funnel aids in filling the radiator and avoid air pockets. Thankyou.


The Lisle funnel has a tall bucket on it. The idea is that after the radiator/cooling system is full, you still have more coolant in the reserve part of the funnel to keep the coolant level far above the radiator and the highest point in the cooling system. This ensures that the air bubbles will go there since they always rise to the top. When it stops bubbling, you know there is no more air in the system and you have successfully bled the coolant.

After you are done, you can close the funnel to dispose of or recycle the coolant remaining in the funnel.

A number of attachments are included with the funnel, so it will work on almost any radiator/cooling system. They even have adapters for those pressurized coolant overflow tanks

 

[billt460]

Originally Posted by Warstud
If you flush with water and drain and fill with 50/50 AF what ratio do you end up with?

To be more accurate, what I generally do, (and I'll admit I'm a bit more anal about it than most), is drain, fill, run, and drain until it drains clear. I then do 2 fill, run, and drains with pure distilled water. I then drain and fill the system with 50% concentrated antifreeze, and 50% distilled water. (Sometimes I'll go a bit heavier on the antifreeze because of residual water than remains in the system). I misstated that in my post. Sorry.

By doing the 2 pure distilled water fill, run, and drains, it helps to evacuate as much tap water out of the system as possible, before introducing whatever your coolant choice and mix is.

 

[maxdustington]

Originally Posted by JC1
Originally Posted by billt460

Instead, just drain the system, then refill it with water, turn the heater control to high, then run the engine until the thermostat opens. Then drain, refill, and repeat until the water comes out clear. Then drain and refill with a 50/50 mix of whatever coolant you are going to use, and distilled water. It's a bit more time consuming that way. But it's easy, and you won't risk damaging anything.


+1, this is what I do.
I'll never do that again, it is WAYYYYYY too slow. Especially if you have to remove the lower rad hose instead of having a drain on or at the rad.

You have to remove the thermostat at the very least, you will end up waiting hours for it to idle and reach temp.

 

[billt460]

Originally Posted by maxdustington
You have to remove the thermostat at the very least, you will end up waiting hours for it to idle and reach temp.

Hours?? I do it in July when it's 110+F out. The first run just takes a few minutes until the thermostat opens. After that it takes very little time. Once you get the engine up to operating temperature, it cools off very little when you drain and refill. You spend far more time waiting for it to drain, than you do warming it up again.

 

[Sayjac]

Originally Posted by Warstud
….If you flush with water and drain and fill with 50/50 AF what ratio do you end up with?...
An AF ratio that will have to be determined with an AF tester/hydrometer. One thing for sure, it will be less than 50% AF concentration with one AF fill.

As for question, when I've done them I've found doing a distilled flush series easiest for me. Rad. d&fs until water runs clear or close. Fill with full strength/concentrated AF to 50% system capacity, top with distilled. Tacoma using PGL AF was done that way, worked great. "Hours" not required for t'stat to open and water to circulate before draining.

 

[TheLawnRanger]

This may be helpful. Watch and decide.
https://www.bluedriver.com/node/114

 

[earlyre]

Jack up car.
Remove splash shield/ under tray
open petcock.
Drain existing coolant into container.
Remove thermostat. (Drop one of the thermostat housing bolts down into the abyss and never find it)
Re-tighten the housing with only one bolt.
Break the petcock trying to close it.
Get mad and curse.
Refill system with RO water (25¢/gal)
Drive to parts store, buy new petcock, and bolts for the housing.
Get your brothers help removing the stub of the old petcock.
Repeat drain/fill cycle, (removing half the system volume each time) until you've calculated a negligible amount of coolant remains.
One or two more with distilled.
One last drain, install new thermostat,and fill system with concentrate.

Realize you bought the wrong coolant.
Buy right concentrate.
Drain system, remove new thermostat,refill with RO water.
Repeat additional drain/fills once per day for the next 5 or do days (removing half the system volume each time) until you've calculated a negligible amount of coolant remains.
One or two more with distilled
Drain, install thermostat, fill with right concentrate.
Jack up car
Reinstall splash shield.

Flush used coolant down toilet to municipal sanitary sewer.

At least that's how it worked for me last summer.

 

[Warstud]

Originally Posted by Sayjac
Originally Posted by Warstud
….If you flush with water and drain and fill with 50/50 AF what ratio do you end up with?...
An AF ratio that will have to be determined with an AF tester/hydrometer. One thing for sure, it will be less than 50% AF concentration with one AF fill.

As for question, when I've done them I've found doing a distilled flush series easiest for me. Rad. d&fs until water runs clear or close. Fill with full strength/concentrated AF to 50% system capacity, top with distilled. Tacoma using PGL AF was done that way, worked great. "Hours" not required for t'stat to open and water to circulate before draining.

It's hard to recommend using Concentrate when it's not readily available. That's why I suggest doing a drain & fill twice with 50/50.

 

[Warstud]

Originally Posted by earlyre
Jack up car.
Remove splash shield/ under tray
open petcock.
Drain existing coolant into container.
Remove thermostat. (Drop one of the thermostat housing bolts down into the abyss and never find it)
Re-tighten the housing with only one bolt.
Break the petcock trying to close it.
Get mad and curse.
Refill system with RO water (25¢/gal)
Drive to parts store, buy new petcock, and bolts for the housing.
Get your brothers help removing the stub of the old petcock.
Repeat drain/fill cycle, (removing half the system volume each time) until you've calculated a negligible amount of coolant remains.
One or two more with distilled.
One last drain, install new thermostat,and fill system with concentrate.

Realize you bought the wrong coolant.
Buy right concentrate.
Drain system, remove new thermostat,refill with RO water.
Repeat additional drain/fills once per day for the next 5 or do days (removing half the system volume each time) until you've calculated a negligible amount of coolant remains.
One or two more with distilled
Drain, install thermostat, fill with right concentrate.
Jack up car
Reinstall splash shield.

Flush used coolant down toilet to municipal sanitary sewer.

At least that's how it worked for me last summer.

I thought that only happened to me.