Neglected coolant system with cheap coolant needs a flush

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Jul 2, 2017
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54
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Tennessee
Im now driving my old families 99 Grand Marquis they bought new with 164K miles now. The maintenance was definitely neglected. After having a leaking heater core I just bypassed temporarily, I found brown water residue on the coolant section.

The radiator has been flushed a lot with water. It still comes out muddy. So I figured I needed a strong radiator flush. Blue Devil makes one with Oil Degreaser inside. What do you guys suggest. I need to do a lot of maintenance on this car so I'm trying to stay budget oriented.
 
Whatever you do, follow the instructions to the LETTER. I've seen strong acids eat through the trans cooler in the rad tank, ruining the trans!
Just stay with it and don't go overboard. If you don't know how much water will be retained in the system, check the final concentration with a refractometer available on Amazon for about $25. You want to end up with 50-60% coolant ratio.
 
To do it right, take out the thermostat temporarily and flush thoroughly with the hose. Disconnect the radiator hoses, wrap a rag around a garden hose and spray through the hoses in both directions until the radiator runs clear. Then connect the top hose to the thermostat inlet and spray out the block. This will get a lot of rust out but not all of it.

After this, put it all back together, and do another flush or two with distilled water before refilling with the coolant of your choice. Going forward, just keep draining and filing the radiator with new coolant every year or two.
 
Does the radiator have a drain on the BOTTOM or is it one of those half-baked ones where it's a few inches up the side?

I've never pulled a block drain, because I don't want to disturb what's down there, but this might be a fix you need.

On my all-iron Cutlass Ciera 3.3 I drove to work for a week one summer, draining the fluid every day after a heat cycle and refilling with water. It got less and less brown (from rust) but was never clear. Still it was much much better. Obviously put pure antifreeze back in to get it to 50/50 when I was done.

The "mud" is rust, oil is a different problem, scale is a different problem. I think you just need patience, more water, and maybe drain the block. Take a picture or save a sample of what you've got so you can convince yourself you're doing better later on.
 
As God is my witness, I've never heard or read of anyone ever unscrewing a block drain.

After sluicing the mud, I'd throw 4 oz. of citric acid powder (the food ingredient) into the radiator and rinse after a 5-minute idle.
G-05 coolant.
I always remove the block drain when changing coolant.
 
Im now driving my old families 99 Grand Marquis they bought new with 164K miles now. The maintenance was definitely neglected. After having a leaking heater core I just bypassed temporarily, I found brown water residue on the coolant section.

The radiator has been flushed a lot with water. It still comes out muddy. So I figured I needed a strong radiator flush. Blue Devil makes one with Oil Degreaser inside. What do you guys suggest. I need to do a lot of maintenance on this car so I'm trying to stay budget oriented.
I run a mixture of evaporust and water for about a week, then flush with water, and finally replace with coolant.
 
As God is my witness, I've never heard or read of anyone ever unscrewing a block drain.

After sluicing the mud, I'd throw 4 oz. of citric acid powder (the food ingredient) into the radiator and rinse after a 5-minute idle.
G-05 coolant.
I have removed block drains, back when they were accessible, and on my old boat I/O as well. But in the case of the boat, you had to do that to prevent the block from freezing...it just used outside river water for cooling, no antifreeze.
The old chevy blocks had drains near, and behind the exhaust manifold.
 
Heck, on Studebaker V8s I was the only guy around who could get them cleaned out and cooling properly after years of neglect. Chemical concoctions wouldn't help a bit. I would pull the core plugs and go in with a high pressure nozzle on the garden hose. Problem solved. Helped do the same on an IH 345 too.
 
As God is my witness, I've never heard or read of anyone ever unscrewing a block drain.

After sluicing the mud, I'd throw 4 oz. of citric acid powder (the food ingredient) into the radiator and rinse after a 5-minute idle.
G-05 coolant.
I took the block drain out on my 93 Tercel many times over the years. The only mishap was the time I misjudged my position and got a good splash of coolant on my face…
 
On this similar car, crown victoria civilian model i did an intake job to discover literal rusty mud in the system.

I had to treat it with oxalic acid (wood bleach) then do a running neutralize with plain soda and then the messy job of draining it out (used a water hose at medium flow to push out the crap, I use mortar mixing trays to catch the refuse and not dump it in a drain.

filled with napa regular green stuff later on. The car loved it,

I think it was rust, scale, dropped out silicate and some stop leak etc - the oxalic acid cleaned it out, literally could see fresh cast metal after one shot. The catch pans had diarhea looking stuff lol.

Never had a good result like that with an off the shelf flush on a severe neglected system other than irontite.
 
To do it right, take out the thermostat temporarily and flush thoroughly with the hose. Disconnect the radiator hoses, wrap a rag around a garden hose and spray through the hoses in both directions until the radiator runs clear. Then connect the top hose to the thermostat inlet and spray out the block. This will get a lot of rust out but not all of it.

After this, put it all back together, and do another flush or two with distilled water before refilling with the coolant of your choice. Going forward, just keep draining and filing the radiator with new coolant every year or two.
Thank you, I didn't think about disconnecting hoses and flushing each one out independently. Makes a lot of sense.

As God is my witness, I've never heard or read of anyone ever unscrewing a block drain.

After sluicing the mud, I'd throw 4 oz. of citric acid powder (the food ingredient) into the radiator and rinse after a 5-minute idle.
G-05 coolant.
Is G-05 a Top Tier coolant. I understand it's a Hybrid something or nother. I'm not to educated on it.
Motorcraft makes a decent coolant flush
I've also heard Irontite Thoroflush is effective
I've also (in non freezing temperatures), poured in 2-3 bottles of the cheap Prestone flush, and drove it around for a week or two before rinsing out

https://a.co/d/gTGx75V
I'll look into Irontite Thoroflush.

I run a mixture of evaporust and water for about a week, then flush with water, and finally replace with coolant.
Thanks
On this similar car, crown victoria civilian model i did an intake job to discover literal rusty mud in the system.

I had to treat it with oxalic acid (wood bleach) then do a running neutralize with plain soda and then the messy job of draining it out (used a water hose at medium flow to push out the crap, I use mortar mixing trays to catch the refuse and not dump it in a drain.

filled with napa regular green stuff later on. The car loved it,

I think it was rust, scale, dropped out silicate and some stop leak etc - the oxalic acid cleaned it out, literally could see fresh cast metal after one shot. The catch pans had diarhea looking stuff lol.

Never had a good result like that with an off the shelf flush on a severe neglected system other than irontite.
The Oxalic acid wood bleach In for sure going to try. I think I'm gonna try a few things like mentioned above. I'm also thinking of CLR cleaner. It's definitely a rusty system. The previous owner "my mother" most definitely ran regular tap water in it for a decade. The neutralizer after this has me worried however. Seems baking soda is recommended. Is there another option I can use..

I entirely forgot about this thread. The car situation is still ongoing. I had some other issues arise I had to take care of.
 
I've been recommended Blue Devil Complete Radiator Flush it seems to be a stronger 3 in 1 with oil degreaser also
 
Thank you, I didn't think about disconnecting hoses and flushing each one out independently. Makes a lot of sense.


Is G-05 a Top Tier coolant. I understand it's a Hybrid something or nother. I'm not to educated on it.

I'll look into Irontite Thoroflush.


Thanks

The Oxalic acid wood bleach In for sure going to try. I think I'm gonna try a few things like mentioned above. I'm also thinking of CLR cleaner. It's definitely a rusty system. The previous owner "my mother" most definitely ran regular tap water in it for a decade. The neutralizer after this has me worried however. Seems baking soda is recommended. Is there another option I can use..

I entirely forgot about this thread. The car situation is still ongoing. I had some other issues arise I had to take care of.

Buy some citric acid and prepare it with 8-10% concentration

Meaning if your system takes 12 qts then you need a mixture or about 1 lb citric acid powder dissolved to fully take care of the rust

Easy way would be to see how much liquid drains out on a standard drain. Then measure it and mix up about the same liquid volume with the 1lb acid (use boiling hot water and mix it in, itll take its time)

Now add it to your system and start the engine, let it run at fast idle for about 30 minutes, then shut off the engine and let it sit till its easy to touch and wont burn your skin off. Drain it out and disconnect hoses as required and use your garden hose to flush out everything so you 100% know everything is clean. Use an air compressor or blower to push out as much water as you can.

now pack it up and pour about 6 qts of oldschool green or g05 (gold) concentrate in the system and top off the rest with water.

The citric acid will eat away the rust, oxalic acid also works extraordinarily well but is a bit harder on your skin. (It can clean really bad sludge from decades old neglected diesels working in the bush and savannah)
 
Jeeez…..after reading threads like these, it makes me really appreciate the fact that I replace the coolant on all of my vehicles on a regular basis……..no matter how much of a pain in the ass it is!
 
As God is my witness, I've never heard or read of anyone ever unscrewing a block drain.

After sluicing the mud, I'd throw 4 oz. of citric acid powder (the food ingredient) into the radiator and rinse after a 5-minute idle.
G-05 coolant.
I remove the block drain whenever I'm changing the coolant. On my 2001 BMW 330Ci I'd get a coolant shower!
 
If it was me, first citric acid, 1kg/2lbs for the whole system. Run for an hour. Do a flush with fresh water, drain and repeat with a dishwasher tab or two - the alkaline detergent will neutralize the acid and the surfactants will degrease the system without foaming too much. Repeat with repeated freshwater flushes until it it doesn’t smell like Cascade/Finish and there’s no foam. Refill with fresh coolant(I’d do G-05 or Peak 10X/Final Charge Pro Series, but Prestone Cor-Guard should be OK) and DI/distilled water.
 
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