engine coolant reservoir

jamesish

Member
Can anyone explain why the reservoir is now (idk how long it has been black) all black and you have to use the dip stick? Like what engineering purpose did this serve?




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Bierpower

Hooked
My best guess would be that with a clear bottle they have to leave one side visible with a level indicator where as with a black bottle and a dip stick they can burry the bottle out the way to make room for more rediculous EPA requirements. Doesn't seem like it would apply to this specific case. Just thinking outside the bottle.
 
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jamesish

Member
I mean.... this just makes no sense. I was looking at my engine today and thinking it’s really not that crowded on the 2.0. Even looks like I can get to the spark plugs without taking off everything.

...then I saw it.
 
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WJCO

Meme King
I mean.... this just makes no sense. I was looking at my engine today and thinking it’s really not that crowded on the 2.0. Even looks like I can get to the spark plugs without taking off everything.

...then I saw it.
If you want to fuck your brain even more....the 2.0 has two coolant reservoirs and the one near the grill is clear like normal instead of black.

And the 3.6 has the coolant reservoir in the same exact spot as the one in your picture by the firewall, but it's clear instead of black.

Where the fuck is 13_gecko_rubi ?
 
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OverlanderJK

Resident Smartass
If you want to fuck your brain even more....the 2.0 has two coolant reservoirs and the one near the grill is clear like normal instead of black.

And the 3.6 has the coolant reservoir in the same exact spot as the one in your picture by the firewall, but it's clear instead of black.

Where the fuck is 13_gecko_rubi ?
Wonder if they are different coolants and it makes it easy to recognize at the dealers for all the dumdums there?
 
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My guess is longevity of the plastic/ cost of material. You ever seen an old or dirty coolant res that used to be clear? It isn't clear anymore and they often crack.
 
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Bear_JT

Hooked
Could the black reservoir on the 2.0 be for a fuel cooler, and the clear one be for engine coolant? I remember my 6.4L Powerstroke had two coolant reservoirs one for engine and a blacked out smaller one for the fuel cooler.
 
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jamesish

Member
Could the black reservoir on the 2.0 be for a fuel cooler, and the clear one be for engine coolant? I remember my 6.4L Powerstroke had two coolant reservoirs one for engine and a blacked out smaller one for the fuel cooler.
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This is what the manual is telling me.

my clear one [6] (right beside it) is for brake fluid.

So in 5 (engine coolant) and 8 (intercooler coolant) it's using the same fluid, Mopar Antifreeze/Coolant. I understand they're separated, as someone else stated, to prevent total damage in case something goes wrong (I would assume if intercooler messes up, the rest of the engine would still be fine). What's killing me though is the all black reservoir.
 
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jamesish

Member
Also, I don't know if this will help someone that may come across this topic wondering the same damn thing but who knows:

The manual states for a 2021 Jeep (at least for 2.0 engine) and it's engine coolant/intercooler fluids [which use the same fluid]: "We recommend you use Mopar Antifreeze/Coolant 10 Year/150,000 Mile (240,000 km) Formula OAT (Organic Additive Technology) or equivalent meeting the requirements of FCA Material Standard MS.90032."

Organic Additive Technology = Organic Acid Technology; long life coolants (llc).

Don't interchange/confuse HOAT, IAT, and OAT. Your engine will fail if you mix.

While the coolant should be purple, the production liquid may be different. Also, light, temperature, and age of coolant may change the color. So never go by color alone.

I don't know why this hasn't been fixed yet in the manuals. You won't find MS.90032. You'll need to use MS.12106. MS.12106 is the 50/50 premixed and exactly what the dealership will use to top off fluids.

The product you need is: 68163849AB. It's pre-diluted, no need to add water. Older Jeeps may take something different, I think pre-13 models are a different ballgame.

Apparently, all this stuff was done on purpose to get you to go to the dealership for service. The different colors, numbers in manuals not matching numbers on Mopar parts, etc.
 
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