Radiator Flush..

[Bucket81]

I purchased a new Denso radiator, and I was planning on flushing the old system before installing the new radiator. But I can't seem to get the system clean. I have ran distilled water through it multiple times, and the coolant comes out black. I've gone through about 10 gallons of water. This is 4 flushes worth...

 

[Brian.]

did you run a detergent (flush cleaner)? Might help speed up the process a little. I think I was clean on the 5th or 6th flush myself.

 

[bootown]

How much are you getting out with each flush? Two gallons-ish hopefully? Might speed things up by draining the engine block too if you're not getting a couple gallons each time. Capacity is 8.5-9.5 qts

Pics are gone, but the write ups may still be helpful idk:

Coolant Flush https://www.toyota-4runner.org/1101715-post35.html
Radiator Replacement https://www.toyota-4runner.org/1034524-post23.html

 

[Bucket81]

did you run a detergent (flush cleaner)? Might help speed up the process a little. I think I was clean on the 5th or 6th flush myself.

I did, I ran 3 bottles of the stuff. Usually ran them for a week each.

How much are you getting out with each flush? Two gallons-ish hopefully? Might speed things up by draining the engine block too if you're not getting a couple gallons each time. Capacity is 8.5-9.5 qts

Pics are gone, but the write ups may still be helpful idk:

Coolant Flush https://www.toyota-4runner.org/1101715-post35.html
Radiator Replacement https://www.toyota-4runner.org/1034524-post23.html

Yeah, I am getting about 2 gallons each time. I'll see if I can find that block drain next time I drain it.

 

[HiluxSurf SSR-G]

it's not oily stuff? hope it's not engine oil or atf that has mixed with the coolant. clean atf is red but if it's burnt, it can become black or dark brown

 

[Bucket81]

it's not oily stuff? hope it's not engine oil or atf that has mixed with the coolant. clean atf is red but if it's burnt, it can become black or dark brown

I haven't seen any water in the oil or the AT fluid. I think some one mixed red and green....

 

[Drcoffee]

You can buy a flush kit which allows you to splice a garden hose into the heater hose. Run the engine while running the hose with the radiator cap off until it run clean. Then open the block drains to empty out the lowest point.

I wonder if someone had used a leak stop product.

 

[HiluxSurf SSR-G]

the block drain is located on the RH side, between the 1st and 2nd cylinders. you have to undo the drain cock (bolt) then the coolant will flow from the union drain just below the drain cock (bolt)

...

Yeah, I am getting about 2 gallons each time. I'll see if I can find that block drain next time I drain it.

 

[Sarki]

I wonder if someone had used a leak stop product.

Unfortunately I have experience with buying a car (Mazda 3) that the seller obviously dumped in some leak stop in an effort to mask the fact that it needed a heater core, a very labor intensive job.
I found that a portion of it had settled in the coolant overflow tank. In speaking with the tech line at Bar’s they said that is very typical and a good way to determine if leak stop has been used.

 

[phattyduck]

I did, I ran 3 bottles of the stuff. Usually ran them for a week each.

That could just be a week's worth of rust then. I wouldn't freak out too much about it (yet). Get some good quality coolant in there and see if it changes color quickly.

-Charlie

 

[Kanoe]

Best high volume flush is a garden hose.

I pull the lower rad hose, thermostat, stick the garden hose in the upper rad hose. Let it run full bore until you get nice clean water out.

Then reassemble the system and do a distilled water flush before finally filling with the appropriate coolant.

 

[Romeo1]

OTC makes this power flush gun called a blast vac. I tried to link the listing but for some reason it kills the post. It’s awesome. Makes very short work of the job. Wished I had this thing 20 years ago when I used to work on semi’s.

Split the system and pull the thermostat. Reinstall the elbow and flush up and down. Then flush the heater cores/rear heater if you have one forwards and backwards.

The design of the cooling on these seems super prone to corrosion/buildup due to the high heater valve mount allowing rust to always form.