Low Coolant Light
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Junior Member
Joined: Jun 2025
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GLC 300
Low Coolant Light
2018 Mercedes GLC 300 w/ approx. 85000 miles. I've had it for 4 months or so and today the low coolant light came on. It happened a few weeks ago, but it was super cold out and sat outside all day long. This a.m. it happened while it was in my garage and now I'm worried about having to spend another crap-load of money on it after dropping $2300 on it 2 weeks ago. At this point, I don't know what to hope for........a small leak, a loose hose, a faulty sensor? Lord.
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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
My coolant reservoir cap was improperly tightened and I lost coolant. The dealer warranted it Just In Case it was defective.
No recurrence. Good luck.
No recurrence. Good luck.
Member
Joined: Aug 2021
Posts: 95
Likes: 26
2017 C300
To be clear, you're topping off the coolant each time the light comes on?
What was the $2.3k used toward? If it was an Service A/B, I would imagine they saw some coolant leakage in the engine bay?
What was the $2.3k used toward? If it was an Service A/B, I would imagine they saw some coolant leakage in the engine bay?
Last edited by DYC300; Dec 30, 2025 at 05:08 PM.
Thread Starter
Junior Member
Joined: Jun 2025
Posts: 17
Likes: 3
GLC 300
The money was only for the diagnostic fee, and changing of the piece above the windshield (and fee for calling out another company to complete it).
Member
Joined: Aug 2021
Posts: 95
Likes: 26
2017 C300
Just thinking out loud here...I think there are three possibilities:
1) The coolant was not topped off at the dealership and you just need to top it off yourself.
2) The coolant level was topped off, but the level sensor is faulty.
3) There is a leak in the coolant system.
Can you check your coolant level right now and confirm that it is indeed low? If you're able to top off your coolant today and observe for a few weeks that you'll figure out if there is a leak.
1) The coolant was not topped off at the dealership and you just need to top it off yourself.
2) The coolant level was topped off, but the level sensor is faulty.
3) There is a leak in the coolant system.
Can you check your coolant level right now and confirm that it is indeed low? If you're able to top off your coolant today and observe for a few weeks that you'll figure out if there is a leak.
