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Leaking Coolant Reservoir? (Always check your fluids!!)

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MercMan54

MercMan54

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**UPDATE**

After driving for 3 weeks, have noticed the dreaded coolant leak is back. Its definitely a slow leak as I have not added any coolant to reservoir.
Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) PXL_20250901_203512272

Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) PXL_20250901_203521456

Looks like I will be joining the club of buying the entire hose assembly to replace the doinky plastic fitting...smh.

Unless, has anyone successfully repaired the plastic fitting/fitted new O-ring solving the leak?

Thank you,
T
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Maximus Gladius

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**UPDATE**

After driving for 3 weeks, have noticed the dreaded coolant leak is back. Its definitely a slow leak as I have not added any coolant to reservoir.
PXL_20250901_203512272.jpg

PXL_20250901_203521456.jpg

Looks like I will be joining the club of buying the entire hose assembly to replace the doinky plastic fitting...smh.

Unless, has anyone successfully repaired the plastic fitting/fitted new O-ring solving the leak?

Thank you,
T
I’ve looked all over for an exact O ring …no luck. I’m hoping someone else can and will confirm it. My O ring developed a flat spot where the leak occurred but then after taking the O ring out and setting it aside for a while, it self healed. I had since bought the new connector with the added bonus hose attached for an extra forced fee. I hope I never have to deal with it again but honestly if the spout that drops out the bottom could just be a barb style, a hose could simply be clamped on right there.
 
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MercMan54

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Update

Hose assembly came in. I removed the reservoir and did not see any cracks or deformations near bottle neck. Removed old plastic connector and didn't notice anything weird with it or the inner washer, but of course replaced it with the new one. Topped off coolant and ran for awhile. No leaks yet...
Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) PXL_20250918_014740761

Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) PXL_20250918_014709294
 

Vtur

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So, a hose and clamp connect to a barb connector that has a special formed oring gssket, then get connect to another similar barb fitting by a preset compression. When oring shrink, it leaks. More unreliable and expensive to replaced. Must be some DEI hiring in the engineering department.
 

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So, a hose and clamp connect to a barb connector that has a special formed oring gssket, then get connect to another similar barb fitting by a preset compression. When oring shrink, it leaks. More unreliable and expensive to replaced. Must be some DEI hiring in the engineering department.
Can you imagine if all the other hose ends under our hood were made the same way?! But there is a lot of plastic to fail.. At least the engineers have also secured our potential need to replace those too at some point.

I looked for an aftermarket coolant tank to replace the plastic one and that connector and it’s not made yet that I could see. I’d replace it if it was made.
 

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ShadowsPapa

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And yet those connection types have been used for decades without problem on fuel systems and other places taking some high pressures and lasting for 30 years.O-rings don't shrink unless exposed to harsh heat or chemicals.

As used in the 1990s - snap on fuel system connectors with an o-ring.
I'm still using them on the same 4.0 I put in my car - it's a tried and true connection type. These came out of a 94 ZJ, I'm still using them today.

Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) 1758204124991-6g
 
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Vtur

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And yet those connection types have been used for decades without problem on fuel systems and other places taking some high pressures and lasting for 30 years.O-rings don't shrink unless exposed to harsh heat or chemicals.

As used in the 1990s - snap on fuel system connectors with an o-ring.
I'm still using them on the same 4.0 I put in my car - it's a tried and true connection type. These came out of a 94 ZJ, I'm still using them today.

1758204124991-6g.webp
Fuel line has lower temp and doesn't fluctuate like coolant.
 

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Fuel line has lower temp and doesn't fluctuate like coolant.
How about hydraulic lines in tractors and excavators - the fluid will scald you.

The fuel line does have a lot more pressure, and, when those lines are near an exhaust header, I'd bet they get hotter than the coolant.

I'd bet the temperature of those lines is about like the temps at the coolant reservoir, which sits high, and doesn't run as hot as the coolant in general. (which will only be about 240 tops at the reservoir)

Next time I run my car, I'll take the temperature of those fittings sitting about 4" from the #1 exhaust header pipe.

Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) 1758216353932-im


Time to get out my infrared thermometer and check...........
Compare temps at the JT reservoir vs. the temps at each fuel line fitting in my car.
 

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So this coolant cross over tube/connector under the radiator was my leaking issue. The replaced both hoses and the plastic mounted cross over under warranty back in February

Jeep Gladiator Leaking Coolant Reservoir? (Always check your fluids!!) PXL_20250918_201558610
 

Vtur

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Can you imagine if all the other hose ends under our hood were made the same way?! But there is a lot of plastic to fail.. At least the engineers have also secured our potential need to replace those too at some point.

I looked for an aftermarket coolant tank to replace the plastic one and that connector and it’s not made yet that I could see. I’d replace it if it was made.
I think a simple reducer barb elbow would works.
 

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Vtur

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So this coolant cross over tube/connector under the radiator was my leaking issue. The replaced both hoses and the plastic mounted cross over under warranty back in February

PXL_20250918_201558610.webp
Did they replaced both hoses because the splice barb isn't offered as a separate part?
 

tysongladiator

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So this coolant cross over tube/connector under the radiator was my leaking issue. The replaced both hoses and the plastic mounted cross over under warranty back in February

PXL_20250918_201558610.webp
There's actually three hoses. And they should have replaced all three.
 

tysongladiator

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Did they replaced both hoses because the splice barb isn't offered as a separate part?
Replacing both hoses was the smart thing to do as they both connect to that connector. And hopefully the dealer was smart enough to replace all three hoses.
 

Vtur

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Replacing both hoses was the smart thing to do as they both connect to that connector. And hopefully the dealer was smart enough to replace all three hoses.
It's cool free under warranty, but on my dime, i won't be replacing those hoses if only the plastic coupler was broken.
 

tysongladiator

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It's cool free under warranty, but on my dime, i won't be replacing those hoses if only the plastic coupler was broken.
It's not an expensive replacement. All three hoses with the connectors was only $150 at the dealer. $150 and a gallon of antifreeze is smart preventative maintenance.

I replaced my hoses last year (177k miles). I had what I thought was a small leak at the connector. When I went to remove the hoses, one of the connectors pretty much crumbled in my hands. The connector had deteriorated. Once I removed everything I noticed one of the hoses was looking a little bad, so I decided to replace all three. The heat breaks down rubber and plastic and even if there's no visible damage to one of the hoses, there may be internal damage. And for $150, it was a smart move.

But, I understand. Everyone isn't like me. Gotta do what you gotta do.✌🏾
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