GLC300 cooling systems
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From: S. Ca.
2015 C300, 2015 F-350 Platinum, 1969 Mach 1 428cj, 2007 Roadking
GLC300 cooling systems
Do the primary and secondary cooling systems use the same fluid? The two systems in our 2016 appear to have different colored fluids.
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From: King George County, VA USA
2017 GLC 300 4matic, 2021 BMW R1200GS
Thread Starter
Senior Member
Joined: Feb 2015
Posts: 393
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From: S. Ca.
2015 C300, 2015 F-350 Platinum, 1969 Mach 1 428cj, 2007 Roadking
There is an expansion bottle towards the front of the engine bay that contains the radiator coolant. There is another expansion bottle towards the rear of the engine bay with the same type of cap. Is this coolant for the turbo or some other type of fluid with a different purpose?
Thread Starter
Senior Member
Joined: Feb 2015
Posts: 393
Likes: 25
From: S. Ca.
2015 C300, 2015 F-350 Platinum, 1969 Mach 1 428cj, 2007 Roadking
Thread Starter
Senior Member
Joined: Feb 2015
Posts: 393
Likes: 25
From: S. Ca.
2015 C300, 2015 F-350 Platinum, 1969 Mach 1 428cj, 2007 Roadking
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From: Thornhill, ON
2018 GLC 43 & 2014 SLK 350, gone 2016 E63 Wagon
My 2018 GLC43 only has one reservoir for engine coolant (similar to what is seen at the front left of your picture). I suspect the other reservoir is for brake fluid? My engine does not have the same cap at the back of the engine that is shown in your picture. Is the cap that you show connected to a pressure type container similar to the engine coolant container shown in your picture or just a reservoir?
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Joined: Sep 2006
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From: Pennsylvania
2019 GLC 63, 2020 C43 coupe
It's the expansion tank for the low temperature cooling circuit, or as some others have said, the coolant for the intercoolers and probably the transmission as well. The cap even has a little radiator on it like the other cap from the high temp circuit. Pretty much every modern turbocharged Mercedes has two separate cooling systems.
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Joined: Sep 2006
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From: Pennsylvania
2019 GLC 63, 2020 C43 coupe
My 2018 GLC43 only has one reservoir for engine coolant (similar to what is seen at the front left of your picture). I suspect the other reservoir is for brake fluid? My engine does not have the same cap at the back of the engine that is shown in your picture. Is the cap that you show connected to a pressure type container similar to the engine coolant container shown in your picture or just a reservoir?
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
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GLC
It's the expansion tank for the low temperature cooling circuit, or as some others have said, the coolant for the intercoolers and probably the transmission as well. The cap even has a little radiator on it like the other cap from the high temp circuit. Pretty much every modern turbocharged Mercedes has two separate cooling systems.
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2022 GLC 300 4 MATIC
That's a good explanation. I have a 24 GLC and yes they do have a split cooling system. Pretty sure most modern 4-cylinder turbo engines are designed that way now. Looking at the fluids it appears that mine has the exact same type at least by color, not sure how it's diluted if at all.
Only oe cap and expansion tank.
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2017 Mercedes GLC300
Curious about this on my 2017 GLC300
If the smaller expansion tank for the intercooler is empty with the car off should it be filled with the same coolant as the larger engine cooling reservoir?
Also, is there an indicator for max fill on the smaller expansion tank?
Getting a P0128 code from the OBD2, could the low level of coolant in the smaller expansion tank be the culprit? Or would that only relate to the engine cooling system?
Also, is there an indicator for max fill on the smaller expansion tank?
Getting a P0128 code from the OBD2, could the low level of coolant in the smaller expansion tank be the culprit? Or would that only relate to the engine cooling system?
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Joined: Sep 2006
Posts: 233
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From: Pennsylvania
2019 GLC 63, 2020 C43 coupe
If the smaller expansion tank for the intercooler is empty with the car off should it be filled with the same coolant as the larger engine cooling reservoir?
Also, is there an indicator for max fill on the smaller expansion tank?
Getting a P0128 code from the OBD2, could the low level of coolant in the smaller expansion tank be the culprit? Or would that only relate to the engine cooling system?
Also, is there an indicator for max fill on the smaller expansion tank?
Getting a P0128 code from the OBD2, could the low level of coolant in the smaller expansion tank be the culprit? Or would that only relate to the engine cooling system?
When you take off the cap to the smaller reservoir, there should be a plastic "T" or "X" that you can see sticking up straight in. Fill coolant to the top of the plastic. Approximately 1" below the cap.
Yes.
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From: Pennsylvania
2019 GLC 63, 2020 C43 coupe
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From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
I first noticed it while off-roading on a steep descent. Warning light.
I didn't even know what the correct fill level was. It's not a mark on the tank - it's a peg-like protrusion from the bottom of the tank.
Now I know how to check when the engine's cold.
