Cooling system flush & burping coolant: what's your process? (1 Viewer)

[abuck99]

Will be digging into my TB job this weekend; which will include a cooling system flush. I'm not planning to to use any cooling system "cleaners" this time around, it was done 2 years ago. I am replacing water pump, thermostat, hoses, radiator, heater T's & related hoses and flushing with many gallons of distilled water.

So whats your flush process for the entire system. How do you open & clear the heater cores of coolant? Do you remove the thermostat to allow better circulation of distilled water through the system?

Interested to hear your process.

2005 LC 186k miles on original cooling system. 1st TB at 95k miles.

 

[Trunk Monkey]

Drain, flush with distilled, and then use one of these:

Pulls vacuum on the whole system (even collapses hoses) and then sucks coolant in for a perfect fill, no burping required.

 

[nissanh]

Disconnect the heater lines and flush those separately: You don't want any dirt going into the heater cores (front and rear).
Bypass the heater core lines.
Remove the thermostat and just install the housing back to the engine
Attach the lower radiator hose to the engine side but don't connect at the radiator
Disconnect the upper radiator hose at the radiator.
A) With the garden hose I flush city water from the upper hose and collect what comes out from the lower hose.
B) Close the lower hose and fill the engine block with city water and drain the water by all at once.
Repeat above two (A and B) few rounds. Then with few gallons of DI water from the store flush it again. Repeat A and B. Also do the same for heater cores.

Install all the lines including the heater core lines and thermostat.

Open the radiator cap and fill the tank about 1 inch below the brim. While the cap is open, (WEAR GOGGLES) start the engine and allow it to come to the working temperature WHILE keeping an eye on the coolant level: Tip- running the AC helps to heat the engine faster. Heater core lines fully open with fan blowing.

Top up as the coolant level goes down.

 

[pokie1313]

Drain, flush with distilled, and then use one of these:

Pulls vacuum on the whole system (even collapses hoses) and then sucks coolant in for a perfect fill, no burping required.

X2
This is one of my favorite special tools.
Makes coolant changes sooo fast and so clean.

 

[Spike555]

If your cooling system is already in good shape and clean, nothing extra is needed, drain, flush with clean water, refill with your coolant.
There will not be enough water left in the cooling system to say so after draining.

 

[bucfl]

If you need pics I have them on my thread for reference. I also used Zerex Asian instead of Toyota coolant. It’s not hard, just a little messy. And as stated already wear eye protection under the truck.

 

[abuck99]

Im trying to verify if coolant constantly flows through the heater core(s) in these trucks. Or put another way, is there no heater valve regulating coolant flow through heater core?

I want to ensure the heater core is open so I can flush the coolant out. Recall procedure on older vehicles with heater valves, but Im not sure about this platform and dont see any mention one way or the other in FSM.

 

[abuck99]

Drain, flush with distilled, and then use one of these:

Pulls vacuum on the whole system (even collapses hoses) and then sucks coolant in for a perfect fill, no burping required.

Nice tool.

Is that a parts store loaner tool? Looks ‘spensive.

 

[Spike555]

Im trying to verify if coolant constantly flows through the heater core(s) in these trucks. Or put another way, is there no heater valve regulating coolant flow through heater core?

I want to ensure the heater core is open so I can flush the coolant out. Recall procedure on older vehicles with heater valves, but Im not sure about this platform and dont see any mention one way or the other in FSM.

Turn the heat on. Done.

 

[Spike555]

This is how I do it, drain coolant, stick garden hose into radiator, remove upper hose from radiator leaving attached to the engine.
Turn on hose.
Start the engine, turn on heater.
Let engine run until nothing but clean water comes out of upper hose.
Shut off engine. Leave hose running until it comes out cold.
Turn off hose. Drain cooling system of water.
Put upper hose back.
Fill with Prestone Universal 50/50. Bleed the system. Fill overflow tank to the brim.
Drive normal, check system level after a few days with engine stone cold.
Fill overflow to the brim one last time.
Done.

I've been doing it this way for 20+ years and it works every time. I have never had a cooling system problem, well, except when the water pump seized and sent my fan through the radiator on my Land Rover, but that was my own fault and a story for another day.

 

[2001LC]

Disconnect the heater lines and flush those separately: You don't want any dirt going into the heater cores (front and rear).
Bypass the heater core lines.
Remove the thermostat and just install the housing back to the engine
Attach the lower radiator hose to the engine side but don't connect at the radiator
Disconnect the upper radiator hose at the radiator.
A) With the garden hose I flush city water from the upper hose and collect what comes out from the lower hose.
B) Close the lower hose and fill the engine block with city water and drain the water by all at once.
Repeat above two (A and B) few rounds. Then with few gallons of DI water from the store flush it again. Repeat A and B. Also do the same for heater cores.

Install all the lines including the heater core lines and thermostat.

Open the radiator cap and fill the tank about 1 inch below the brim. While the cap is open, (WEAR GOGGLES) start the engine and allow it to come to the working temperature WHILE keeping an eye on the coolant level: Tip- running the AC helps to heat the engine faster. Heater core lines fully open with fan blowing.

Top up as the coolant level goes down.

I'm sorry and I'm really Not trying to get on your case. But I really don't like this procedure. First never put city water in coolant system, distilled only. Second, I never remove a hose unless absolutely necessary.

Im trying to verify if coolant constantly flows through the heater core(s) in these trucks. Or put another way, is there no heater valve regulating coolant flow through heater core?

I want to ensure the heater core is open so I can flush the coolant out. Recall procedure on older vehicles with heater valves, but Im not sure about this platform and dont see any mention one way or the other in FSM.

FSM states to "turn cabin heat up all the way up" front and rear IIRC. I've no idea why, as coolant does flow through constantly. No more replacing stuck valve, which once was used to open/close flow to heater core(s). It also means; coolant doesn't sit stagnant in heater core.

 

[abuck99]

FSM states to "turn cabin heat up all the way up" front and rear IIRC. I've no idea why, as coolant does follow through constantly. No more replacing stuck valve which used to open flow to heater core(s). It also means; coolant doesn't sit stagnant in heater core.

Ok that answers my question regarding heater valve-

 

[2001LC]

FSM Coolant replacement:
HINT:
Adjust the air conditioner set temperature to MAX (HOT).
(2) Maintain the engine speed at 2,000 to 2,500 rpm.
(3) Press the inlet and outlet radiator hoses several times by hand to bleed air.

 

[cwmoser]

I've never used distilled water - just water from the city tap.
We don't have hard water or much lime in it anyway.

I do it like this:
- Open Radiator Drain at bottom of Radiator and let fluid start draining out.
- Open Radiator Cap and insert Hose from City Water into Radiator.
- Crank Engine with Heater on and let water flush out for a few minutes.
- Remove City Water hose and let more water drain out radiator.
- Close Drain at bottom of Radiator.
- Pour in a couple gallons of 100% Antifreeze
- Crank Engine and let it run for a few minutes
- Add more Antifreeze or water as Radiator level goes down.
- Button up and take for Test Drive.
- Next day when cool check Radiator and top off.


So what is the down side of doing it this way??????

 

[2001LC]

Again do NOT use anything but distilled or demineralized water. The minerals in the tap water will damage your coolant system. Google you'll find the sciences behind how the mineral react to form deposit.

Warning don't use: Prestone makes a "tee" to connect into the coolant hoses, which connects to a garden hose for flushing. For this reason I do not trust any prestone product.

Coolant system care is on par with oil changes in importance to long term health of engine.

CARCHEX Asks: Can You Mix Tap Water with Engine Coolant?

 

[Trunk Monkey]

I'd probably soften that down a little and just say "best practice" would be distilled if you have it, but if you do or have used city water, your engine isn't going to blow up tomorrow. I know in the microcosm of Mud some peeps so "do NOT" and think if they have, then they've killed their motor. I used tap water on my 60, didn't affect anything. All Toyota radiators I've had have gotten crusty build ups in them, maybe tap water leads to that happening more quickly, dunno.

I would say more important is not mixing coolants. If you drain and find someone along the way put in green coolant, then either refill with that or thoroughly flush and refill with red. I wouldn't drain green and refill red without a good flush.

 

[2001LC]

Perhaps your right TM, my language is strong. But I'm very passionate about this issue!

BEST PRACTICE without a doubt. I too used tap water or any old antifreeze/coolant for decades in the 60's & 70's even into the 80's when I keep cars and average of 3 years. But back then I regularly pulled radiators and hauled off to radiator repair shop to be rebuilt. They'd boil clean in a acid bath, then weld the leaks. We also had to replace or have rebuilt the heater cores regularly. Additionally we'd have to replace the water control valve, as it would freeze up from deposits. This was all mainly is due to deposit, even the hoses would build up deposits in 3 years. These deposit do more damage than just clog coolant system, they eat away at it.

These deposit were/are do to the minerals in tap water more than anything else.

Pull the cap on any radiator that uses tap water for three years or more and you'll see deposits on fines. I can tell you on my 01 (The King) which I babied with only distilled water (And Toyota Red) for ~14 years, the fines were clean.

There is a reason Toyota went to only permix in the Pink and states on/in jug of SLL pink, OM & FSM Don't add water or use only Distilled water or mix with distilled water only.

I can also say; that even taking extra steps to blow out system with compressed air or a mechanical flush will not remove all fluid from system.

No one knows how long a 2UZ-fe will last. We know one hit 1 million miles and was ready for more. We also know it was maintained with best practice according to Toyota service history.

 

[geanes]

@2001LC Yeah, I can't use city water here in Central TX. Our water reads at 23 on a hardness scale! Even with a water softener and reverse osmosis, we are still at 6. Introducing raw tap water would destroy my cooling system due to the HIGH mineral content (nearly destroyed the dish washer and clothes washer and clogged every single water outlet within weeks of purchasing the house). Introducing softened water would run trace amounts of salt through the system which ain't good either. In either case, my cooling system would be damaged severely. Distilled/demineralized water ONLY for me. The cost isn't that bad (certainly WAY less than replacing a damaged cooling system).

 

[pokie1313]

Nice tool.

Is that a parts store loaner tool? Looks ‘spensive.

Think I paid about $115 for mine. Have used it like 8 times in two years so definitely paid for itself over going to a shop.

 

[atnolan94]

I did this this morning because I lost about a gallon of coolant because i forgot to connect a hose after doing my rear heater bypass. Not a full flush BUT I did bleed/burp it.

1. Fill radiator cold
2. idle the car up to temp then do a quick lap around the block to open the thermostat up and pull coolant into motor, Heater on highest setting
3. kill the car wait 10 mins (no particular reason why, I've never had a problem pulling my cap off a hot radiator, assuming its not overheated) and fill radiator back to top
4. Drive another lap around the block but romp it pretty good, high RPM to get the coolant flowing, again heater on highest setting
5. top it off, and continue doing this til your coolant level in the radiator stays constant

Only thing I would do is check a couple hours later to ensure you coolant level is still good assuming you drove around a bit. For example, I did this process this morning before work, and I will check it to see if I need to top off before I head home. A good 10-15 minute 75mph, 2000+ RPM run would be perfect to get the air out....just so happens that's exactly what my commute consists of. From what I've read, these 4.7s are pretty good self-burpers and tend to bleed well on their own with normal driving.

Maybe there's a more efficient way, but this has worked for me on many vehicles.