Coolant loss thoughts

[1lieutenant]

My 2021 Mercedes GLC 300 just gave a ”check coolant level” warning. Waited for the engine to cool then opened the expansion tank. There was coolant in there but it is low. I will be bringing it to the dealership tomorrow but would appreciate your thoughts on potential problems. My thoughts always seem to go to worst case scenarios such as head gasket. I did not see any apparent leaks, but the engine bay is tight.

For background, I purchased the car new. It has 27K miles.

 

[LongTime_Lurker]

Don't see any external leaks or dripping underneath?

I asked an Estonian mechanic about a slight coolant level drop over a few years and he said it was because of "long time".

 

[andyd]

Is it still under warranty? Don't sweat the small stuff. Let the service guy know.The low coolant level sensor on my528e was a simple float worked to save me from overheats a few times

 

[1lieutenant]

Yes. this is why it is going to the dealer to tomorrow.

 

[Ursatdx]

I'd top it off. If you'd be more comfortable, let the dealer top it off.
If the dealership tops it off you have a record of the low coolant level and they should
use the correct A/Freeze. Monitor the level for a while and see if the "problem" persists.
The finest cars on the planet need fluid level maintenance.

 

[TheOilWizard]

My 2021 Mercedes GLC 300 just gave a ”check coolant level” warning. Waited for the engine to cool then opened the expansion tank. There was coolant in there but it is low. I will be bringing it to the dealership tomorrow but would appreciate your thoughts on potential problems. My thoughts always seem to go to worst case scenarios such as head gasket. I did not see any apparent leaks, but the engine bay is tight.

For background, I purchased the car new. It has 27K miles.

Very unlikely to be anything serious with that low of mileage. The dealer will want to do a pressure test, but even then they may not be able to find the source of the leak if it's small enough. Even with new cars, it's been my experience that the coolant has to be topped off occasionally.

 

[Ursatdx]

Yes. this is why it is going to the dealer to tomorrow.

They will top it off and send you on your way.

 

[TheOilWizard]

They will top it off and send you on your way.

A good dealer should at least offer a pressure test for a coolant loss concern.

 

[1lieutenant]

This is what I would expect. I do want it to be documented by the dealer. Should they use an exhaust gas analyzer to evaluate for coolant?

 

[dbias]

most new cars I’ve bought have needed coolant within the first six months of ownership. Idk if they’ve all had air in the system that worked it way to the bottle or if hoses expanded due to breakin Anyway once I’ve topped them off the coolant loss ceases.
Also when I’ve added coolant it’s only been when it gets to the low mark. I’ve never had a low coolant light.

 

[1lieutenant]

Went to the dealership. They examined the car and found no evidence of a leak. Service writer stated ”likely evaporated “. Interesting.

 

[MattPersman]

Going through many many hot cold cycles through the miles and years your level will drop certainly. So a on the border of ok when new can get to low not that far down the road some are pretty sensitive as well

 

[Donald]

Went to the dealership. They examined the car and found no evidence of a leak. Service writer stated ”likely evaporated “. Interesting.

Does not matter what they wrote. They saw it was low and acknowledged.

I have seen where when coolant level was almost low and when the weather turns cold it would turn on "coolant low".

 

[HowAboutThis]

My 2021 Mercedes GLC 300 just gave a ”check coolant level” warning. Waited for the engine to cool then opened the expansion tank. There was coolant in there but it is low. I will be bringing it to the dealership tomorrow but would appreciate your thoughts on potential problems. My thoughts always seem to go to worst case scenarios such as head gasket. I did not see any apparent leaks, but the engine bay is tight.

For background, I purchased the car new. It has 27K miles.

It's normal to have to top off coolant, say, once or twice per year. If it's just normal evaporation type loss, you'll notice it's in range in August and by November when temps drop it'll be close to low. Temps affect the levels. I often top off a bit above halfway between L and H in the winter and by spring it's sitting near H when cold. Any the next winter I do the same. Probably add about a cup of coolant every year. I'm not worried as long as it doesn't increase in amount.