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2019 C300 here, found some coolant on the floor of my garage the other day after driving the car around. Got home, popped the hood, took the plastic engine cover off, and notice the hose coming from the reservoir into the engine was leaking. Seems to be leaking around that connector that I'm pointing to here in the photo.
Didn't want to address it right then and there as the engine was really hot and wasn't sure if this system is pressurized at this point or not.
All that being said, any ideas what the fix here might be? Any parts I might need to replace? Any suggestions for anything here? Thanks a lot.
2019 C300 here, found some coolant on the floor of my garage the other day after driving the car around. Got home, popped the hood, took the plastic engine cover off, and notice the hose coming from the reservoir into the engine was leaking. Seems to be leaking around that connector that I'm pointing to here in the photo.
Didn't want to address it right then and there as the engine was really hot and wasn't sure if this system is pressurized at this point or not.
All that being said, any ideas what the fix here might be? Any parts I might need to replace? Any suggestions for anything here? Thanks a lot.
the coolant hose connector must use an O-Ring seal, right?
Buy a few spares and replace one when cold.
Each time a coolant connector is disturbed, seal must be replaced new because it rolls over itself during insertion. Use silicon lube to help.
These are the ultimate "one time use" parts like the aluminum bolts that snap at 5NM.
Last edited by CaliBenzDriver; Jun 21, 2026 at 04:29 PM.
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2019 C300 Coolant Leaking Issues
