Coolant leak by oil cap
MBWorld Fanatic!
Joined: Jul 2017
Posts: 1,004
Likes: 148
From: Richmond, VA Metro Area
2005 C230 Sport Sedan-6 Speed Manual
This thread may help.
It is difficult to see detail in your video. You may want to take some still photos of the area and see whether one of the sharper-eyed users of this forum sees a source of the leak. You may want to dry everything off. Then start the engine and see if you can spot the location of the leak.
The thread I linked has information on the plastic coolant pipes that are a common source of leaks on the M271 engine. I've had to replace all three of the pipes on my car.
This is a guess, but the first place I would check is the area where the top coolant hose meets the water pump.
Good luck.
It is difficult to see detail in your video. You may want to take some still photos of the area and see whether one of the sharper-eyed users of this forum sees a source of the leak. You may want to dry everything off. Then start the engine and see if you can spot the location of the leak.
The thread I linked has information on the plastic coolant pipes that are a common source of leaks on the M271 engine. I've had to replace all three of the pipes on my car.
This is a guess, but the first place I would check is the area where the top coolant hose meets the water pump.
Good luck.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 3,275
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From: BC, Canada
2003 C230K Coupe Orion Blue
MBWorld Fanatic!
Joined: Jul 2017
Posts: 1,004
Likes: 148
From: Richmond, VA Metro Area
2005 C230 Sport Sedan-6 Speed Manual
I agree. I ignored Slammer's advice and ended up changing my pipes one at a time. It will be less total work if you change all three at the same time.
The pipe that is between the back of the engine and the firewall is the most difficult one to reach.
While you have the cooling system open, I recommend that you consider replacing the thermostat. I, and several other owners, had a problem with the thermostat opening to soon. This caused the engine to run at a low temperature which triggered a Check Engine Light. You can read about the issue here.
The pipe that is between the back of the engine and the firewall is the most difficult one to reach.
While you have the cooling system open, I recommend that you consider replacing the thermostat. I, and several other owners, had a problem with the thermostat opening to soon. This caused the engine to run at a low temperature which triggered a Check Engine Light. You can read about the issue here.
Junior Member
Joined: Feb 2026
Posts: 22
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From: Kentucky
2004 C230K 2 door coupe 1.8l m271 6 speed manual
