2018 Yukon XL 4x4 38k miles leaking coolant

[Msuforeman]

I moved my wife's Yukon last night and there was a large puddle of coolant under it. The reservoir was down about 3/4 gallon. I filled it back up and ran it as well as let it idle parked for 20 mins and no drips anywhere. Y'all have a clue what's going on?

Thanks!!

 

[Big Mama]

Loose reservoir cap? Did you get a recent oil change from a ****** lube place?

 

[Msuforeman]

Loose reservoir cap? Did you get a recent oil change from a ****** lube place?

It was tight when I checked it and I do my own oil changes.

 

[Big Mama]

Thought so. Any cracks in the reservoir? Sounds like it had to be under a good bit of pressure to loose that much. Have you been under it yet to trace the leak? Near driver or passenger side? Front or firewall? Heater all the way on and off?

 

[Msuforeman]

Thought so. Any cracks in the reservoir? Sounds like it had to be under a good bit of pressure to loose that much. Have you been under it yet to trace the leak? Near driver or passenger side? Front or firewall? Heater all the way on and off?

I used a paper towel to wipe around the bottom but it was dry. Yes I have been under it and can't find where it originates from. I topped it off the other night and it hasn't leaked again. Very weird.

 

[Big Mama]

Chalk it up I guess though I hate doing that. She didn’t notice any lights from heat or low reservoir?

 

[OR VietVet]

Do you have the means to pressure test the system?

 

[Msuforeman]

Chalk it up I guess though I hate doing that. She didn’t notice any lights from heat or low reservoir?

Nope--No lights.

 

[Msuforeman]

Do you have the means to pressure test the system?

I do not. I guess I will just watch it and then take it to the dealer if it happens again.

 

[OR VietVet]

You can get universal pressure testers at ebay for around $50. Lots of attachments.

 

[Fless]

You can get universal pressure testers at ebay for around $50. Lots of attachments.

You can also "rent" them for net no cost (when you return them) from many parts places like Advance Auto. Loaner tools.

 

[Doubeleive]

go take it for a "spirited drive" about 5 miles of good fast highway speeds and then park it on a level surface and put some clean cardboard under it (cover the entire engine/radiator area) and then check it in the morning. any spots on the cardboard in the morning will point you to the source.

 

[G00se]

I have the same issue. Every 500-750 miles, I notice my engine temps creep past 210 and know it's time to fill the coolant reservoir again. Let us know how the it goes.

 

[Aggie76]

Just had my 2015 in for another issue and they noticed the low reservoir and then found a tiny bit of fluid under drivers side top of radiator that they said would leak when under pressure and warm. They replaced the radiator and thermostat under warranty under PI1513F per the service invoice I have. The tech said they are finding quite a few with it. I had not noticed any drips on garage floor or the smell of coolant.

 

[Christian80]

I moved my wife's Yukon last night and there was a large puddle of coolant under it. The reservoir was down about 3/4 gallon. I filled it back up and ran it as well as let it idle parked for 20 mins and no drips anywhere. Y'all have a clue what's going on?

Thanks!!

Coolant reservoir develops cracks as it is made from bad plastics. I am already replacing the second one. They have a revised part which I am installing, when I replaced it the first time they did not so I went with what they had. The cracks are very fine and it leaks slow enough that it evaporates before you can see it usually only when it's very hot and under pressure. If it starts leaking more all of a sudden you will find the tank empty and you will see coolant under the reservoir or even under the SUV.

 

[Msuforeman]

Coolant reservoir develops cracks as it is made from bad plastics. I am already replacing the second one. They have a revised part which I am installing, when I replaced it the first time they did not so I went with what they had. The cracks are very fine and it leaks slow enough that it evaporates before you can see it usually only when it's very hot and under pressure. If it starts leaking more all of a sudden you will find the tank empty and you will see coolant under the reservoir or even under the SUV.

This was a puddle that was 30" in diameter.

 

[Christian80]

Just had my 2015 in for another issue and they noticed the low reservoir and then found a tiny bit of fluid under drivers side top of radiator that they said would leak when under pressure and warm. They replaced the radiator and thermostat under warranty under PI1513F per the service invoice I have. The tech said they are finding quite a few with it. I had not noticed any drips on garage floor or the smell of coolant.

I thought that bulletin applyes to tru ks only, do you have a truck or SUV?

 

[Christian80]

This was a puddle that was 30" in diameter.

It might be the radiator leak then, there are some issues with them although I thought only with Sierra and Silverado. Check hoses and clamps too.

 

[G00se]

Coolant reservoir develops cracks as it is made from bad plastics. I am already replacing the second one. They have a revised part which I am installing, when I replaced it the first time they did not so I went with what they had. The cracks are very fine and it leaks slow enough that it evaporates before you can see it usually only when it's very hot and under pressure. If it starts leaking more all of a sudden you will find the tank empty and you will see coolant under the reservoir or even under the SUV.

Can you post the part number or link to this revised part? Your description fits what seems to be happening with mine. Thanks in advance.

 

[Christian80]

Can you post the part number or link to this revised part? Your description fits what seems to be happening with mine. Thanks in advance.

84368362 new part.
22856231 old part.