96 4.0 85,000 miles Coolant Question

The coolant in my Jeep looks very old and brownish and I have no clue when, or if, it was ever replaced. My question is should I drain and replace it or flush and replace it. I am nervous that once it runs through the flush machine too much sediment might break loose and then cause the radiator to leak. What do you guys suggest? I'm also going to be installing a new OEM fan clutch since mine is on the way out

I'll bet you don't need a new clutch. Also, yes, flush it. I did this on mine at 86,000 miles. If you clog the radiator (highly unlikely), so be it, it was on its way. If you don't flush it, though, you will ruin the water pump and have poor cooling (not good on an already crappy system). Just get one of those garden hose flush kits and run water through it for several minutes. That should take care of it.

I did mine at about that mileage, too. Be sure to remove the overflow bottle and hose that out. Wait till you see the disgusting turd-mud inside. I had about 2 inches built up in mine.

FWIW, I rebuilt my who cooling system chasing a leak. Radiator, water pump (bad), fan clutch (bad) , all hoses (ends were cracking; didn't know it till they were off), hose clamps, temp sender, thermostat, (brown/ancient, I think original) coolant.

Flush. It's not going to get better if you change coolant - it's going to get worse.

If it clogs up the radiator (or if you're worried,) after you flush the system, take the radiator out and take it to a shop - ask them to "boil" it. That gets it cleaned in a hot tank - and most shops will also pressure-test the radiator and repaint it afterwards. If a cooling system has been neglected, it's amazing how many leaks a flush will uncover...

Use distilled or RO filtered water when you mix the new coolant - NO TAP WATER! That's probably part of what got you in this fix in the first place.

Add Water Wetter, if you can get it. It's made by RedLine, and it WORKS.

Repeat every two years (except for the boiling - if you keep up on your flushes and coolant changes, you should be fine.)

Service lives -
I've been informed that OEMR radiators typically last 120-150kmiles from the factory. For Modine or Performance Radiator (my preferred brands,) that's break-in mileage. I've been hearing mixed reports lately on GDI - but I don't use them. Modine and Performance both WORK for me. (I prefer Modine, but Performance is usually easier to get. Three of my four XJ radiators are Performance, the other is Modine.)
Fan clutches - typically five years at the outside (no matter what my auto instructors say. Five years is based upon about 30 years' experience working on this stuff. I started early.) It is a good idea to date your fan clutch when you replace it - if you're not sure, just turn it until you can see where you wrote the date. A Sharpie pen is good for this - an engraver is a lot better. I've been doing it that way for years - makes it easier to keep everything straight when you write it down.

After you get done flushing, I'd probably also get the hoses done. I think they're usually good for five years, but I change them every Smog (two years,) and keep the old one in the back for emergency spares. Murphy's Law being what it is, I don't have failures while I've got spare parts. Go figure.

Anything else?

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