Edit: Rust in Coolant Flush

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florida95fzj

Joined
Jul 27, 2021
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Location
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The PO mixed incompatible coolants and I had a sludgy mess when draining my cooling system.

I'm not sure if it is related but I have rust in the system and the coolant would never flush clear.


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So the nasty brown stuff was before or after the flush?
I've never used the funnel thing, just fill the radiator with the engine off till full, cover the cap opening with my palm, pump the top coolant hose a few times to move the air around, top off, seal with hand, pump, top off..... until when I pump the top hose coolant dribbles into to the overflow.
Then I start the engine and monitor the coolant level and top off as needed, till it won't take anymore. Seal with cap and top off overflow bottle. and let it get up to temp.

Been doing it this way for near on 30 years on every type of vehicle I've owned... has never failed.
 
Rusty Marlin said:
So the nasty brown stuff was before or after the flush?
I've never used the funnel thing, just fill the radiator with the engine off till full, ...
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That brown stuff was after flushing everything until clear and doing the block drain. Got about 10 gallons out including my flush water. I did not pull the thermostat out before doing all of this.

I should have looked at the Thermocure stuff. I have no idea what color it was.

The orange crap in that big black pan was the original color when I pulled the lower hose.
 
JunkCrzr89 said:
Every time I’ve used Thermocure, it has come out gray in color after running through the system.
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Good to know. I have a feeling I am in for a long flushing process. I already have 80 gallons of coolant flush from a diesel motorhome in my garage. I guess I am going to add some more home depot buckets to my collection.

I guess I will try to bleed it again and then go for a drive tomorrow. I was planning only to stop the bleed process once there were no more bubbles. This has worked for me in the past although I can't say I've been able to get to 207F just sitting in the driveway with the AC on.
 
If you're going to flush with a hose, you need to remove the thermostat.
if you are doing a chemical flush then it just a drain everything, back fill with distilled water and the chemical flush of choice and follow the instructions.
I use Blue Devil. Run it back and forth to work for a couple of days to get the thermal cycles and flush, fill, flush, fill....till clear with hose water and final flush with distilled. Then top off with Zerex for Asian (Toyota and Lexus).
 
I forgot one other thing. I was working on the passenger's side near the radiator and this black screw cap fell down to the ground. I could not figure out where it came from. Could this be a bleeder cap on my aftermarket radiator? I probably should have did a pressure test. Anyone know what this thing is?

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This is a bit of a puzzle, I am thinking there was some serious corrosion which has become dislodged and is causing some type of blockage. Def need to use thermocure to break it down but before doing that, I think you need to do the 3 part back flow flush. Someone can jump in and fill it in, but its back flow of the radiator, back flow of the heater cores, and back flow of the coolant into the engine. I just did all of this and its been weeks since its been hot/raining in FL so between kids n work, I work on it when I can. I had to resort to Thermocure since after flush 10x, I was still brown. Now I am getting some clear distilled.

Change that thermostat, water pump and fan clutch if you can. Extra insurance.
 
lp2k said:
This is a bit of a puzzle, I am thinking there was some serious corrosion which has become dislodged and is causing some type of blockage. Def need to use thermocure to break it down but before doing that, I think you need to do the 3 part back flow flush. Someone can jump in and fill it in, but its back flow of the radiator, back flow of the heater cores, and back flow of the coolant into the engine. I just did all of this and its been weeks since its been hot/raining in FL so between kids n work, I work on it when I can. I had to resort to Thermocure since after flush 10x, I was still brown. Now I am getting some clear distilled.

Change that thermostat, water pump and fan clutch if you can. Extra insurance.
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Appreciate the tips. The storms and wind has made driveway work tough these days.

I figured out part of the problem. I didn't read the manual on that spill free funnel. They say to stop after the thermostat opens and the bubbles stop. The issue might have been too much pressure/expansion for the higher temp and nothing to backstop that pressure since there was no rad cap on with the funnel in place.

I have a new radiator, water pump, thermostat, and fan clutch. I am trying to clean things out before putting the new parts in. I need to figure out how to back flush the engine and then repeat what I've already done.

I went back out tonight and ran it back up to 184F. It took 3 more quarts of water and the color this time was only dark yellow or light brown. That was about 30 minutes of idle with the AC on.
 
lp2k said:
You are running it with the heat on high and the rear heater on high also right? I know we are both in FL, but we have to run the heat and tuff it out... I am baking since I am not running my AC when I am doing these flushes...
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For part of the time I ran the heat on max. I also turned the AC compressor on but left the temp control on hot. I think this keeps the heater valve open and it raised the coolant temp because the compressor was running.

My rear heat is disconnected - I think. There are two firewall pipes without any hoses. I guess I need to verify that and learn the correct routing.

I flushed and back flushed the main heater core. It actually wasn't that bad. The radiator was a disaster with sediment. Once I figure out how to flush and back flush the engine, I should only have to worry about what's caked on the hard pipes and inside the hoses. What came out of the engine drain was not that bad for whatever that is worth.
 
Njck22 said:
looks like stop leak to me.
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I hope not. My Blackstone oil analysis came back with no coolant or water found so I don't think it would have been a HG leak. I guess there could have been a leak in the radiator itself they were trying to cure. I may send in this coolant for testing as well.

My hope/theory was this sludge was a result of the PO mixing Toyota red with the orange coolant from the auto store. I haven't found any pictures of what happens when you do that.
 
You got it to 207°F sitting in the driveway?

You have a problem.

Did you install your thermostat correctly? First pointing the right direction in the hole, second, with the jiggle vale at 12:00 in the hole so the air can bleed out past the tstat. Any time you are doing flushes, you SHOULD be doing it WITHOUT the tstat installed so it can all free-flow better. The engine will not come up to temperature as much. It will stay cold.

I still don't understand why everyone keeps wanting to do chemical flushed on these, when all that's going to do is dislodge any stuff that's keeping the holes from leaking. In all my years, I have never seen a radiator plug UNLESS there was a catastrophic failure and got oil in the coolant, or simple, basic maintenance was NEVER performed.

The chemical flushes will erode the insides of your steel coolant lines, eat the aluminum oxidation from the aluminum parts, exposing pits and potential leaks, and remove any "stop leak" crud the PO put in it before he sold it to you.

Nothing good EVER comes from this level of flushing.

Just use distilled water a number of times and call it good.
 
BILT4ME said:
You got it to 207°F sitting in the driveway?

You have a problem.

Did you install your thermostat correctly? First pointing the right direction in the hole, second, with the jiggle vale at 12:00 in the hole so the air can bleed out past the tstat. Any time you are doing flushes, you SHOULD be doing it WITHOUT the tstat installed so it can all free-flow better. The engine will not come up to temperature as much. It will stay cold.

Nothing good EVER comes from this level of flushing.
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Correct, it got that hot after about 30+ minutes in the driveway. I lost track of time. There's no doubt everything the PO did to the cooling system made it worse. I am at week 4 of ownership.

I didn't touch the thermostat or change any of the parts yet. I am trying to get this orange/green coolant sludge mix out (or worst case - stop leak) before installing the new radiator so I don't plug it up. I am going to pull the thermostat out tomorrow. I do think it opened because a lot of air bled out between 170-180F.

I did the chemical flush to hopefully break apart the sludge in parts of the cooling system that won't be replaced. The only things I am not replacing are the hard pipes and heater core. I don't know if water alone will do the trick but I'll be flushing the chemical mix out ASAP anyway.
 
BILT4ME said:
You got it to 207°F sitting in the driveway?

You have a problem.

Did you install your thermostat correctly? First pointing the right direction in the hole, second, with the jiggle vale at 12:00 in the hole so the air can bleed out past the tstat. Any time you are doing flushes, you SHOULD be doing it WITHOUT the tstat installed so it can all free-flow better. The engine will not come up to temperature as much. It will stay cold.

I still don't understand why everyone keeps wanting to do chemical flushed on these, when all that's going to do is dislodge any stuff that's keeping the holes from leaking. In all my years, I have never seen a radiator plug UNLESS there was a catastrophic failure and got oil in the coolant, or simple, basic maintenance was NEVER performed.

The chemical flushes will erode the insides of your steel coolant lines, eat the aluminum oxidation from the aluminum parts, exposing pits and potential leaks, and remove any "stop leak" crud the PO put in it before he sold it to you.

Nothing good EVER comes from this level of flushing.

Just use distilled water a number of times and call it good.
Click to expand...
My block was apparently rusted because my coolant kept returning to rust colored after numerous distilled water flushes. Thermo cure cleaned it up. After about 18 months it’s still quite clean with the exception of slight signs of rust particles under the radiator cap. Rust does not transfer heat well so it’s gotta go.

What I don’t understand is why anyone has a problem simply filling their cooling system and allowing it to self bleed. Fill slowly, run it until the coolant begins to drop in the radiator, add more coolant until you can’t add anymore. Then drive it as you normally would checking the recovery tank each morning until the morning you check and the tank coolant level hasn’t dropped.

I’ve done V8’s, V6’s, 4 bangers and my Cummins 5.9 this way. No black magic or fancy tools.
 
Ditto- I couldn’t see clear water until I brought thermocure in. It was always rusty. I’m going Toyota red so I need it done right.

my 0.02, if it’s still coming out brown or murky, I think your at wits end and need the thermocure

Like I said, after thermocure, it got hot air again like my wife’s new car does
when she came by and felt how hot it gets now, she was amazed
 
lp2k said:
Oh yea and just go ahead and change that rad cap. I didn’t think I needed to on a 156k mile truck but yes u do. I couldn’t get the old one to hold pressure
Click to expand...

Will do. Will be looking forward to that last step.
 
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