Engine Coolant Questions

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Tech-Mechanic

New Member
Joined
Nov 12, 2021
Messages
20
Reaction score
11
Location
Longmont, CO
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

New Member
Joined
Feb 1, 2019
Messages
8
Reaction score
4
Location
New York
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?
Deleted post
 
Last edited:

LibertyTC

Well-Known Member
Staff member
Moderator
Joined
Oct 24, 2008
Messages
9,190
Reaction score
1,836
Location
B.C. Canada
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.
 
Last edited:

Ksat

Full Access Member
Joined
Nov 11, 2018
Messages
315
Reaction score
136
Location
ny
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.
 

Boueux

Active Member
Joined
Dec 28, 2023
Messages
121
Reaction score
65
@Ksat

Since you’ve recently appeared and been kind enough to answer some of my questions.. I’m having a difficult time corroborating the correct version of HOAT for our 2006 KJ Renegade 6cyl 3.7L .. everywhere I look online for the concentrate tells me a different Mopar parts number, very confusing

I found someone at a local auto parts store who said they could order it.. and I know it takes HOAT, and Haynes says 13 quarts.. but nowhere can I find the amount of water to concentrate needed. To make it more confusing, the parts store computer said that for every other brand of coolant only one gallon was required for the 2006, but for Mopar HOAT it said 13 gallons is required.

We pointed out that this was possibly a typo, as it takes 13 qts, but what with all of the potential problems the wrong stuff can cause I want to be certain.

I can’t read it in the images above.. Do you by any chance know the current US Mopar part number for the concentrate? Where to source it? OR should we just make it easier in the long run by starting over with the Zerex equivalent ( or whatever is asker to get ahold of? )

I understand flushing the who system and starting fresh is a good idea, but can this be done with gallons of distilled water in a garage in the winter.. without literally driving it.. or does it need some pressurized extraction system to do it properly? Don’t want to make any mistakes.

Many thanks for your time In responding.
 

JeepJeepster

Full Access Member
Joined
Dec 15, 2004
Messages
8,932
Reaction score
327
Location
Dem hollers in Ky
I've always used zerex G05. Its a pale yellow (color doesnt matter, FYI) and Ive never had any issues. Its readily available pretty much anywhere but I normally buy concentrate from Napa when its on sale.

I mix 50/50 with distilled water. I've never flushed a cooling system and never will, but I maintain my cooling systems so its not needed.
 

Boueux

Active Member
Joined
Dec 28, 2023
Messages
121
Reaction score
65
Great to hear, thank you Very much @JeepJeepster . I see Zerex G05 is specified for the 06 also. Looks like I’m switching over from whatever is currently in there.. but I don’t think I can avoid flushing, dont really want to take the chance.
 

Ksat

Full Access Member
Joined
Nov 11, 2018
Messages
315
Reaction score
136
Location
ny
What I described earlier is kind of a flush-as-you-go idea and is what I've found to be the easiest and most complete way to do it. It typically takes a number of days to do,, however, so it shouldn't be done if you expect temps to dip below freezing.

You could speed up the process by doing a drain, refilling with distilled, idling the vehicle until full operating temp is reached (and heat is nice and hot), shut down/allow engine to cool, then repeat the process until, again, what comes out is almost as clean as what you put in. Doing it that way, tho, can sap up a good part of the day and and wastes lots of gas, especially if your cooling system has been neglected. Long periods of idling is not really good for the engine, either.


It might be best to just throw something in there for the time being such as Prestone green, which claims to be compatible with all antifreeze types, and just wait until the warmer weather and do it the way I described originally.
 
Last edited:

1ino

Member
Joined
Nov 9, 2023
Messages
31
Reaction score
16
So many different colors, why can't they all just get along and go back to green only.
I use Delo truck antifreeze, 500k life, red in color close to the pink my toyota came with, my chrysler minivan has blue, if I ever change it will be using Delo, the liberty will be using Delo for sure.
I really dislike the orange to me it looks like the old rusty cooling systems.
 

Latest posts

Top