Adding coolant
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From: Cary, NC
2024 AMG EQE SUV , 2021 E63S Wagon - gone, 2018 E63S Sedan - gone
Adding coolant
I find once a year that I need to top off the coolant tank on my E63S. I've seen no leaks or seepage so I wonder if this is just a bit of evaporation or pressure release. Anyone else experience this?
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Joined: Apr 2004
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From: Idaho
'19 E63S
just the other day the coolant light came on on mine the first time ever, right after coming back from a shop for a different issue (one thinks they'd have paid attention to a low level) . . . However, I have never noticed any indication of a leak of any sort so I just figured its just normal consumption, not any reason for concern. I'm @ 55,000 ish
Last edited by sixfive; Mar 22, 2023 at 05:49 PM.
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From: New Orleans Area
2015 E400 Sedan
coolant supposed to be closed system ie never gain nor lose any.
Only way could lose in proper system is Pressure gets too high and cap vents some steam which will have some liquid in it.
This would take a lot of time to lose a pint or so of liquid in steam form.
May I suggest a pressure test of system and Importantly pressure test cap.
You pump up to pressure of cap on car and see if it holds for couple of hours.
FOr cap you pump up to check relief pressure is OK and then let it shut and hold a pressure for coupe of hours.
If all OK then my guess is system generates too much pressure and you vent it as steam.
Signs would be greasy messy around pressure cap from steam venting.
Coolant pressure sensor would let you know this but alas never seen that done.
Or worse case small cracks in block, head or head gasket and coolant is burned off in combustion.
Can pass compression tests here unless engine is HOT when testing.
Only way could lose in proper system is Pressure gets too high and cap vents some steam which will have some liquid in it.
This would take a lot of time to lose a pint or so of liquid in steam form.
May I suggest a pressure test of system and Importantly pressure test cap.
You pump up to pressure of cap on car and see if it holds for couple of hours.
FOr cap you pump up to check relief pressure is OK and then let it shut and hold a pressure for coupe of hours.
If all OK then my guess is system generates too much pressure and you vent it as steam.
Signs would be greasy messy around pressure cap from steam venting.
Coolant pressure sensor would let you know this but alas never seen that done.
Or worse case small cracks in block, head or head gasket and coolant is burned off in combustion.
Can pass compression tests here unless engine is HOT when testing.
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MBWorld Fanatic!
Joined: Feb 2007
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From: Cary, NC
2024 AMG EQE SUV , 2021 E63S Wagon - gone, 2018 E63S Sedan - gone
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From: Toronto, ON, Canada
2020 AMG E63S Wagon, 2021 Subaru Outback Limited XT
Whether it was coincidence or not, I had the low coolant warning come on at around 27K miles, a few days after a track day in mid-October 2021. This was a wet day on a short track (Driver Development Track at Canadian Tire Motorsports Park), so speeds were not terribly high and neither was the stress on the engine. The engine certainly did not overheat during the session. Unfortunately I never checked/worried about the coolant prior to the light coming on.
I'm still under warranty, so I took it to the dealer. They pressure tested the system, reported "no fault found" and topped up the coolant. I'm now at 35K miles, and (now that I'm checking regularly...) I haven't seen any further loss of coolant.
Ivan MacKenzie.
I'm still under warranty, so I took it to the dealer. They pressure tested the system, reported "no fault found" and topped up the coolant. I'm now at 35K miles, and (now that I'm checking regularly...) I haven't seen any further loss of coolant.
Ivan MacKenzie.
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c450
Old comment but I’d like to say something anyway.
Whether it was coincidence or not, I had the low coolant warning come on at around 27K miles, a few days after a track day in mid-October 2021. This was a wet day on a short track (Driver Development Track at Canadian Tire Motorsports Park), so speeds were not terribly high and neither was the stress on the engine. The engine certainly did not overheat during the session. Unfortunately I never checked/worried about the coolant prior to the light coming on.
I'm still under warranty, so I took it to the dealer. They pressure tested the system, reported "no fault found" and topped up the coolant. I'm now at 35K miles, and (now that I'm checking regularly...) I haven't seen any further loss of coolant.
Ivan MacKenzie.
I'm still under warranty, so I took it to the dealer. They pressure tested the system, reported "no fault found" and topped up the coolant. I'm now at 35K miles, and (now that I'm checking regularly...) I haven't seen any further loss of coolant.
Ivan MacKenzie.
