# What's in my coolant tank? (pics) Please help!



## maddog814 (12 mo ago)

Hello ... I have a 2013 Cruze with 1.8L engine, 175k miles. I noticed recently that the temp gauge was not getting to operating temp, so I checked the coolant level and found this.



















I initially thought this was oil, but I'm not sure. It is more BLACK than it is BROWN. I wiped the funnel on a towel and wiped the oil dipstick on the same towel so you can see the colors side by side. Below is funnel from coolant tank on LEFT and oil dipstick on RIGHT.










The first thing I tried was to do a quick flush the coolant (did 4 cycles of distilled water driving 15-20 min between cycles) and replace with new coolant, hoping this would clear it up. Now I've driven for a few days and it has reappeared. The oil does not look frothy when I checked it.

I have never changed the transmission fluid on this vehicle. Is it possible there is a leak where transmission fluid is getting into the cooling system? Any help is appreciated, I don't know where to start. Thanks for reading.


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## JLL (Sep 12, 2017)

Transmission fluid has no way of getting into the coolant. That most likely engine oil. Or your cooling system has been severely neglected. It's very possible for the oil to enter the cooling system without coolant entering the oil galleries.


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## maddog814 (12 mo ago)

JLL said:


> Transmission fluid has no way of getting into the coolant. That most likely engine oil. Or your cooling system has been severely neglected. It's very possible for the oil to enter the cooling system without coolant entering the oil galleries.


If the radiator has an internal leak, couldn't that cause transmission fluid and coolant to mix?


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## JLL (Sep 12, 2017)

maddog814 said:


> If the radiator has an internal leak, couldn't that cause transmission fluid and coolant to mix?


Most earlier Cruze's have a separate transmission cooler. I guess your's could be an acception.


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## atikovi (Dec 27, 2011)

JLL said:


> Most earlier Cruze's have a separate transmission cooler. I guess your's could be an acception.


Then what are those 2 fittings on the right for?









I would check if the radiator doesn't have the internal cooler. If it does, replace it ASAP and flush the transmission a few times before it blows.


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## JLL (Sep 12, 2017)

atikovi said:


> Then what are those 2 fittings on the right for?
> 
> 
> 
> ...


Those fittings are for a model with an internal transmission cooler. Some Gen 1 Cruzes have internal coolers others have external coolers. Most early model (11-14) Cruzes I've seen anyway have an external cooler sandwiched between the radiator and condenser. Most of the 15's and 16's have internal transmission coolers. As you pointed out the only way for the OP to know is to open the hood and look.


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## maddog814 (12 mo ago)

atikovi said:


> Then what are those 2 fittings on the right for?
> 
> 
> 
> ...


I believe the transmission cooler is inside the radiator. So replace the radiator and flush the transmission fluid?


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## Maqcro1 (Apr 29, 2019)

maddog814 said:


> I believe the transmission cooler is inside the radiator. So replace the radiator and flush the transmission fluid?


don’t forget about the oil cooler which is known to leak. Especially the 1.8l engine.


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