I believe there are 2 block drain plugs on the bottom sides of the engine. For a full drain of the entire system, I think you're suppose to remove those and drain the coolant from the engine too. Maybe your leftover coolant was hiding out in there?

 

these jeeps do not use green coolant. mixing two different chemistries of coolant is not great, you might want to consider flushing it all.
http://www.wkjeeps.com/wk_maintenance.htm#COOLING

 

oi, that's what I was afraid of. I'll look into it and find the locations, unless anyone has a link they can share? Thanks. And yes, I know about the HOAT coolant...if I could afford 4 of those, I could afford the professional flush...I was hoping to fix the overheating at idle and wait on the full flush until my tax returns...

 

even w/o removing the block plugs (which may be seized depending on if you live in the rust belt) you can flush it yourself by taking out the tstat, fill the system with water and run it for a little while, then drain. keep repeating that until it drains clear. make sure to open air vent plug on water pump to get as much as you can in/out each time.

once it's draining clear, drain what you can and fill the rad with undiluted coolant. that will mix with the water left in the block and get you somewhere around 50/50. if you flush you can switch to another coolant, but the HOAT is recommended because it's iron block/aluminum heads/aluminum water pump etc so there is a lot of potential for corrosion.

 

I did head gaskets on my 08 4.7 still have half a gallon leftover that came out, but didnt go back,in. System is full. Doesnt overheat...cant explain it...

 

I would quickly flush the system again. Bad things happen when you mix different coolants. It can gunk your cooler lines and be very expensive mistake.


Zerex G-05 is HOAT and is cheaper than Mopar stuff. Flush what you have inside with destilled water couple of times and fill with fresh coolant.



Jeeptorino did you burp the system with heating on full heat ? I guess heater core might be still full of air.

 

...Jeeptorino did you burp the system with heating on full heat ? I guess heater core might be still full of air.

Don't think there is a valve in the blend-air system. The engine coolant should always be flowing through the heater core. Perform a final bleed to clear air pockets by parking facing uphill, run until thermostat opens, and finish at higher engine rpm.

Keep radiator and overflow tank level near top. Air should "burp out" as thermostat opens and air flows upward from the heater core to the block to the upper radiator.

 

I know about the HOAT coolant...if I could afford 4 of those, I could afford the professional flush...

The Zerex G-05 is $18/gal of the 50/50 mix at O'Reilly's. That's only $5 more per gallon than their house brand, green, cheap stuff.
https://www.oreillyauto.com/shop/b/chemicals---fluids-16461/antifreeze-16506/antifreeze-17780/e59e98316193/1994/ford/explorer?q=zerex&brandNameId=Antifreeze%2FCoolant+Zerex%7C2766&storePrice=range%5B0.00%3A20.00%5D
The concentrated Zerex G-05 is $21/gal. Throw in $2-3 at the grocery store for a gallon of distilled water and now you have 2 gals of a HOAT coolant mix for around $26 +/- (w/ tax)! It's not that expensive.

Don't get me wrong...I'm a cheap-a$$ at heart all day long! But when you sit down and really look at the numbers, it makes it easier to pay a little more to do it the right way.

 

yeah, i'll have to run and flush with the water. i had no idea about the block retaining so much coolant. so annoying.

and fyi, green cheap stuff is $7.98 @ walmart lol. i know mixing them isnt good. ill have to run it for a month until i get the money t9gether for the good stuff and flush it again the right way.

 

Be careful mixing the two coolants, as it can sometimes cause them to "gel" up in the system. If that happens, you'll loose all cooling capabilities and you'll overheat.

 

This thread got me thinking about what happens when we take our Jeeps into our mechanic shops even if they are good. Do they go through all the trouble and steps outlined above to be sure there is a complete fluid change?

 

I don't trust Valvoline lube center...



I did the flush at Valvoline yesterday, and contrary to what is stated on their website and their products, the lube center has a "universal" coolant that works with all manufacturer specs (HOAT, OAT, conventional, etc). Which has to be a joke. I couldn't find anything on it. I at least have the system flushed with the same fluid now, and after I get my taxes back I'll have a real shop put the official HOAT stuff in, none of this "magic fluid". So frustrating.

This must be what they are referring to as the universal coolant, their maxlife product: https://www.valvoline.com/our-products/antifreeze-products/maxlife-antifreeze-coolant

 

*removed

 

I did some research, using the green stuff isn't the end of the world...but it needs to be flushed every 30k miles...whereas the OAT/HOAT can last up 150K. And apparently Prestone guarantees their coolant can be mixed with any other without issues. And apparently using anything BUT green in older vehicles is bad. I definitely like the idea of the longer-lasting coolant...the "gel" effect isn't immediate, so if I only do it for another 6k miles I won't have horrible effects...but it will start building up silicate "residue" on the radiator and water pump, and if I try to go for the long haul I will hurt the radiator, pump, and thermostat. So definitely going to do a flush. I'm not bothering with the bottom mount thermostat again, as I killed my shoulders and back working on that hose clamp.

I checked, and Valvoline quickie change does use vehicle specific coolant:
THE COLORS OF COOLANT
You might be thinking, "What color is antifreeze? What color is Dex-Cool®?" It's true, coolant liquid comes in different colors, most commonly green (orange for Dex-Cool®). Each color is a unique formula that should not be mixed. The below chart will help you decipher which fluid is in your vehicle. Reminder, you can often find the recommended type of coolant in your vehicle's owner's manual.

TYPE INHIBITOR TECHNOLOGY ZEREX COOLANT VEHICLES COLOR
IAT (Inorganic Additive Technology) Silicates Zerex™ Original Older Vehicles
GREEN

OAT (Organic Acid Technology) Organic Acids Zerex™ Dex-Cool®
GM, Saab, VW
ORANGE

HOAT (Hybrid OAT) Silicates & Organic Acids Zerex™ G-05™
Ford, Chrysler, European
YELLOW

HOAT (Hybrid OAT, Phosphate-free) NAP Free ZEREX™ G-48 BMW, Volvo, Tesla, Mini, others
TURQUOISE

P-HOAT (Phosphated HOAT) Phosphates & Organic Acids ZEREX™ Asian Vehicle
Toyota, Nissan, Honda, Hyundai, KIA & other Asian vehicles PINK / BLUE
Si-OAT (Silicated HOAT) Silicates & Organic Acids ZEREX™ G-40 Mercedes-Benz, Audi, VW, Porsche, others
PURPLE

GENERAL INFO

Green anti-freeze/green coolant
These are the traditional type of anti-freeze most commonly used in North America. Their silicate and phosphate composition provides protection for aluminium and bare iron surfaces. They need to be changed every 30,000 miles or once every two to three years.

OAT anti-freeze/OAT coolant
OAT stands for Organic Acid Technology.OAT anti-freeze contain ingredients such as 2-EHA, sebacate and other various organic acids. Unlike green anti-freeze, they generally do not contain silicates or phosphates. Usually, OAT-based coolants will be dyed a different colour to green anti-freeze. They must be changed once every five years or 150,000 miles.

HOAT anti-freeze/HOAT coolant
HOAT stands for Hybrid OAT. These antifreeze use organic acids but not 2-EHA and usually include silicates to provide protection for aluminium surfaces. HOAT anti-freezes are used by many European car manufacturers, although they are also used by American companies such as Chrysler and Ford. A HOAT coolant will need to be changed every five years or 150,000 miles.

 

It's going to be a real workout to get the wrong stuff out of your engine. Personally, I'd do it as soon as you can. Drain the system from the petcock and then remove the thermostat and use a shop vac at that location to extract the remaining coolant in the engine.

Can I mix green coolant with orange coolant?
This is one of those questions usually asked after the fact, and usually engine damage has already occurred. The green and orange coolants do not mix. When mixed together they form a gel-like substance that stops coolant flow and consequently the engine overheats.

There are some coolants that claim compatibility with Dexcool, but I would rather err conservatively and add what the system is supposed to take rather than gamble. To guard against major engine failure, read on.

- source: https://www.autoblog.com/2009/12/28/coolant-color/

It's just not worth the risk and consequence.

Buy one of these - https://www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY - they're definitely worth the price of admission.

 

HOAT, OAT, SCHMOAT!!! IMO, the cooling systems in our Jeeps are too critical to save a buck or two by purchasing so called magic "works in all" coolants. This, along with differential/xfer case oils, is the reason I ONLY USE Mopar stuff in these systems. In almost 15 years now of owning DCX/FCA vehicles, I've never had even a hint of a problem with any of these systems other than the thermostat housings. If owners "stay on top of" scheduled interval and preventative maintenance there should never be a problem. It seems that the biggest problem is "know nothing" mechanics that think they know all the answers. As I said, the only issues I've had with the cooling systems are the cheap stamped metal thermostat housings on my 5.7's. I played with those several times, including surfacing them, new o-rings and still developed small seeps or leaks over time. I finally had enough of it and replaced the housings in both vehicles with Billet Technology machined aluminum housing.....now no more problems since.

 

@90grandoneer - solid advice! I am still considered upgrading to the billet thermostat housing. You might have just pushed me over the edge as my first thermostat leak was at 40k.

I think I spent 20 bucks for a gallon of Mopar brand coolant (undiluted) at the dealership. And I got a free show watching a woman literally scream at the service adviser. So for 20 bucks you get 2 gallons of 50/50.

I would drain that universal coolant, shop vac what you can out... Buy a Lisle no-spill funnel and fill and circulate with 100 percent distilled water. Repeat this until you get clear water on the drain.

Our Jeeps are extremely fussy about products, and buying peace of mind is cheaper than "hope".

 

This must be what they are referring to as the universal coolant, their maxlife product

And the link off that page to their article on "How To Choose The Right Type of Engine Coolant" still states:
"Each color is a unique formula that should not be mixed"

If you can get all of the original stuff out (which is highly unlikely they did), then yes, the universal stuff will probably work fine. But why take the chance?