2004 coolant drain

Randallissimo

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2004 Liberty renegade 3.7L 4WD

I lost a fair amount of coolant while changing the passenger side valve cover gasket, so I replaced it with water from the garden hose as a temp fix. I grabbed some Prestone HOAT coolant to do a drain/flush/refill. I put a 5/8" open ended wrench on the draincock on the lower drivers side of the radiator, and gave it a quarter turn CCW, and nothing. Not a drop. I worked it back and forth, I even poked around a bit with a nail up in the nozzle, but it remains as dry as a ****.

What is my situation, is it clogged, like totally 100% clogged? I don't want to be driving around with the coolant thinned out like this. Plus, it has been 7 years since the last flush, and I am in SW Florida.
 

Randallissimo

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I dropped the lower hose, opened the fill tank cap, and cracked open the top hose. I let it drain for an hour. I blew compressed air in the fill tank, which forced some more fluid out. I even turned the engine over for a few seconds, but all that came out is 8 quarts. The manual states 14 qts. Where are the other 6?

My intention was to drain and flush, then refill with Prestone HOAT, but now I am confused. The stuff that came out is 7 years old, even though it still looks pretty good and clean. If I apply water to flush it, then with thinned out or mostly water still in the engine that won't fully drain out, how do I know how to mix the concentrate I picked up?

I haven't started to flush it yet, in case someone tells me it's not a good idea. What should I do? I do need to get it back on the road soon.
 

LibertyTC

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Prestone HOAT ?
Mopar Hoat comes from the dealer, it can be full strength or 50-50 mix.
The only other one that is real HOAT is Zerex G-05 from wallmart & other locations Napa etc / 50-50 pre-mixed.
If you had good heat in the jeep & nothing is plugged up, i would just re fill w/ hoat as above.
Fill Let it run with cap off for a few minutes, it should drop, refill to cold line.
Put cap back on & then see if it drops overnight, refill to cold line & monitor levels for a couple of days as necessary.
 

Randallissimo

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I live in the sub tropics, so I never use my heat. I have had no overheating issues, or any coolant based complaints. I just thought since I lost fluid during the valve cover change, I think it was the heater core, and topped that off with hose water, that I should be flushing and replacing.

Hey, I'm all for topping off with real HOAT if that makes sense. (I now see that the Prestone is compitable with, but not HOAT) Only thing is, I don't know what the orange coolant that I drained actually is, and there is half of it still in there. If I get some Zerex G-05 and fill what is needed with that, would that be a confident move? Remember, I topped off with hose water to replace the fluid I lost doing the valve covers.

Am I over thinking this?
 

lfhoward

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Even though Prestone says it is “universal” and “compatible with” HOAT, people’s experience here is that it is NOT. If it is mixed in, it will cause gelling and clumps that clog the coolant passages, radiator, and heater core, as well as eat away the water pump impeller. It is bad news in our Jeeps. Flush if needed and then use HOAT (Mopar or Zerex G05). Hose water is not good for topping off because it has dissolved minerals. Need to use distilled water for the 50/50 mix.
 

LibertyTC

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Yes tap water can then cause corrosion.
IMHO when unsure of what is in your cooling system, the best course of action is finding a shop that has the pressurized distilled coolant re-circulating machine with HOAT.
Jeep dealers often have this machine and it's good piece of mind going forward.
Jeep should have placed a warning sticker on the tanks.
 

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Randallissimo

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If I want to do it myself and use Mopar or Zerex HOAT, how can I get all of the coolant and flush water out of the engine before filling with 50/50 mix?

Here is what I have done so far. Pulled lower hose at radiator, pulled both lower heater core hoses at engine, pulled top radiator hose at radiator, pulled lower hose from fill tank, pulled hose from fill tank to radiator. I have blown compressed air into every opening, and gained about one more quart, so that puts me at 9 quarts drained of 14. Jeep is parked with the front at a slight down incline.

Where are the other 5 quarts?

edit: OK, I pulled thermostat and blew some more air in. I measured exactly 9.5 qts in all total that came out. So the radiator is drained, the heater core is drained, and the fill tank is drained. With the thermostat out, is there any possibility of there being more coolant in the engine block, or is about 10 qts what this engine really holds?

I am perplexed.
 
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Ksat

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Buy about 6 gallons of distilled water. Remove coolant reservoir cap. Drain coolant that's in there by removing lower rad hose where it connects. Let'r drain. Refill with just distilled water. Drive vehicle for a good half hour at least in the course of your normal routine. Drain again/fill with distilled again/drive again. Keep doing this until what drains out the bottom starts going clear. At that point you'll know whatever was in there is out. Next, refill with FULL STRENGTH cheapo green antifreeze (or any full strength of your choice).
 

Randallissimo

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For the record for any future readers. I drained out ~10 qts of coolant. Disconnected all hoses and flushed it out to my satisfaction, everything ran clear right away. Drained again. Filled with ~10 qts 50/50 Zerex. Starting by putting in 1 gal concentrated then 1 gal distilled water straight into the block from the top radiator hose, followed by about 2 qts of 50/50 mix into fill tank while engine was running and heater was on. Ran it for a few errands over two days, topped off just a little in the fill tank.

10 qts, not 14 qts. I have good heat, no overheating, loss of cold fill level, or any other issues.

Done.
 
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