Oh Snap - The Magic Yoo-Hoo Machine: Brown Coolant

[RangerJoey]

Hi All,
I'm trying to flush the cooling system on a '99 4.0 OHV and first drained the coolant on a cool engine. Rather disgusting:


Nasty stuff. I then removed the thermostat, threw a bottle of Prestone flush + distilled water in there, let it idle with the heat maxed and drained again:


Not much difference. I did a 3rd flush with just distilled water, (again, still no thermostat and up to operating temp with cabin heat on):


Clearly, a lack of progress. I've since done a 4th flush too. The first flush had a lot more sediment and color was darker, (only because I can compare side by side), but even this 4th or 5th flush (with the peacock open), is still pretty nasty. The consistency of each flush is definitely more water-like so I'm not worried about oil contamination, but does anyone have any ideas if this is normal neglect or something else going on? I see no signs of leakage but I'm concerned the sediment I keep pulling might be one of those radiator sealers:


At this point, I think I've gone through about 8 gallons of distilled water. I'll keep going to do it right, but is there light at the end of the tunnel or should I sell this stuff to neighborhood kids?

 

[Uncle Gump]

What does the oil look like?

 

[85_Ranger4x4]

Not unheard of for southern trucks to just run water. Good for plugging up heater cores with rust. Is it from down south?

 

[fastpakr]

I'd a garden hose and run that through until things look clean, then switch to distilled once it runs clear.

 

[RangerJoey]

Thanks all! And nope, truck has been in MD it's whole life. Just means southern weather one summer, then New England-like the next
Oil is clean though. Did a change shortly before this. Still super clean. But I like the garden hose idea. How would I do that though? I've seen things like splicing into the heater core and stuff.
I should also mention, I have new hoses and t-Stat housing but wanted to wait until things ran clear. Would that help now or stick with the plan?

 

[alwaysFlOoReD]

When you have it up to temp, is the rad the same temp on all areas? I've pulled a rad apart that had water like yours and the sediment clogged the bottom third of the rad. No amount of flushing is going to clean that out.

 

[adsm08]

Could be worse. I changed my radiator one day because it was leaking a bit, coolant was black.

 

[Dirtman]

Mmmmmmmm i just made myself a big glass of ovaltine.

 

[black_demon69]

A few things
1 add flushing T s to the heater core Inlet and outlet (you will need a female hose adapter to connect to hose also)
2 take hose out of over flow and shorten it with angle and clean over flow (with shorter hose it won't suck coolant in right off the bottom so let's crap settle over night and acts like a filter of sorts) also over will have to be cleaned and refilled periodically.
3 flush system with tstat removed and 1T open and other T with hose attached open T is used to give short bursts of air while flushing
4 replace tstat and remove as much water as possible before refilling with a 60/40 mix of global (yellow) coolant

It will have to be done again but give it about 3 months because it is almost impossible to get it all the first time.. Then it might even need to be done again after that.

 

[RangerJoey]

Thanks all for the input so far - much appreciated! I think longterm, I have no problem replacing the radiator. I wouldn't mind doing it now, but I know it's a rabbit hole thing with me, (leads to water pump, belt, etc). After thinking about it, I probably should play it conservatively and swap the radiator. I can't get my temp gun to get an accurate reading with the engine running to figure out if it's sludge in the passageways or the radiator itself, but considering I was already going to do the hoses & t-stat, why not pull the unit and trash it?

Next question though: If doing the radiator, what else should I be doing with all that clearance? Water pump? Idler Pulley? Serpentine Belt? Oh, and before even starting this, should I continue flushing until I can get things as clear as possible? I'd hate to dirty up those purdy hoses I just picked up Just thinking that water's never going to look good until I get the old parts out of there.

 

[fastpakr]

At the very least, pull the radiator and flush it separately. You can flip it upside down, spray it on both directions, etc until you're sure things are coming clean.

 

[91stranger]

I need to flush mine too. It looks a lot like that lol.

 

[RangerJoey]

Silly question, but which way do I turn the fan clutch bolt to remove it?
I got the radiator and shroud out in 20 minutes. Then - boom - stopped all progress.
The shroud says it's RH thread on this 4.0 OHV. So does that mean turn left/passenger side (when facing the truck)? Or right, driver's side.

 

[Curious Hound]

As you face the head of the bolt, turn it counter-clockwise.

 

[RangerJoey]

Thank you! And seriously dense, but that's towards passenger side facing truck?