Engine Coolant Questions

Tech-Mechanic

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I did take a look at the "required Fluids" sticky but, I have some deeper questions.

I bought an '07 KJ back in November. I noticed the day after I got it that one of the tanks on the radiator is held together with epoxy. So, I got a new radiator for it in December but, it's been so freaking cold I haven't put it in yet. It's now developed a pretty constant drip under pressure so, time to do it.

I know that the OEM coolant is HOAT which is usually gold in color. But, the stuff that's in it now looks orange, maybe a little on the brown-ish side. (I needed to put some in the reservoir and I used the orange stuff since I think that's what it's running)

Before I got this Liberty, I had been driving the same car for 25 years. So this rainbow of engine coolants is all kinda new to me... Not sure what the right move is here.
I'd like to use the manufacturer specified fluid but, if it's been running the orange stuff, can I put the gold HOAT coolant in after the radiator install?
Is it possible I'm running the "gold" coolant now, and it's just gotten old enough to look brown?
Can I mix these two types of coolant? If not, should I stay with what I believe to be the "orange" coolant, since it may be difficult to get all traces of the old stuff out of the system?
 

Lardog

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I did take a look at the "required Fluids" sticky but, I have some deeper questions.

I bought an '07 KJ back in November. I noticed the day after I got it that one of the tanks on the radiator is held together with epoxy. So, I got a new radiator for it in December but, it's been so freaking cold I haven't put it in yet. It's now developed a pretty constant drip under pressure so, time to do it.

I know that the OEM coolant is HOAT which is usually gold in color. But, the stuff that's in it now looks orange, maybe a little on the brown-ish side. (I needed to put some in the reservoir and I used the orange stuff since I think that's what it's running)

Before I got this Liberty, I had been driving the same car for 25 years. So this rainbow of engine coolants is all kinda new to me... Not sure what the right move is here.
I'd like to use the manufacturer specified fluid but, if it's been running the orange stuff, can I put the gold HOAT coolant in after the radiator install?
Is it possible I'm running the "gold" coolant now, and it's just gotten old enough to look brown?
Can I mix these two types of coolant? If not, should I stay with what I believe to be the "orange" coolant, since it may be difficult to get all traces of the old stuff out of the system?
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LibertyTC

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Tap Water? You don't want any tap water in the block/system, de-mineralized water only, even when mixing down Hoat full strength.
You can't always rely on color. Here is New Mopar Hoat example.
You must be registered for see images attach

The problem is that without the previous owners receipts, or confirming they have always used Hoat, you are guessing what might be in there.
It's easy enough for a shop to top up /use the wrong coolant, at which point the best course of action may be to get it into a dealer for a flush.
Some Dealers have a pressurized re-circulating machine that removes the bad, and in with fresh Hoat. That gives you complete piece of mind.
My dealer flush, I told then to set it at-45c and it was done right. Change HOAT coolant every 5 years.
Mixing hoat with the wrong coolant, can cause coagulation/ gel, and to potentially cause damage to the plastic water pump impeller.

Yes always use Mopar Thermostat and if hoses need replacement use mopar they fit perfectly & marked correctly.
The mopar lower rad hose has a spring in it, to prevent bending/pressure collapse.
You must be registered for see images attach

The substitute Hoat is Zerex-G05.
 
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Ksat

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I would completely flush out what's in there and add in coolant of your choice. That way there's no guessing. I personally use cheap, old fashioned green in my KJ.

A complete flush means draining what's in there (via removing lower rad hose) refilling with distilled, driving vehicle, then repeat. When what drains out looks as clean as the distilled you put in, you're done. Do a final drain and refill with a full-strength coolant. Drive vehicle then use a coolant tester to make sure you have the proper freeze protection u need.

It may take a lot of draining/refilling cycles before you're fully flushed, so plan on buying 6 or more gallons of distilled. You don't need to do this all in one day. Just drain and refill as you normally use the vehicle. That's what I do. Obviously, keep on eye on the outdoor temps. Any flushing I do on my vehicles is usually di in the late spring or early fall where I don't have to worry about freezing temps plus I can live with having the heat on in the cab.
 

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