M276 engine noise
Thread Starter
Joined: Nov 2016
Posts: 7,847
Likes: 3,498
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
M276 engine noise
I have a 2014 C350 Sport with about 70,000 miles. I’ve changed the spark plugs and have serviced the tranny, along with regular oil change at 5000 mile intervals using Mobil 1 0W-40. I’ve noticed a low knocking noise, somewhat irregular, from the rear of the engine on the driver’s side. Seems worse on startup, but doesn’t go away completely. Any ideas? Thanks.
Thread Starter
Joined: Nov 2016
Posts: 7,847
Likes: 3,498
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Thanks, but no. That’s not it. This isn’t rattling and it’s not in the front of the engine. Plus my engine serial number isn’t in the range affected. This noise is more of a low frequency knocking and it doesn’t go away after starting. I’m beginning to think it’s the high pressure fuel pump.
Thread Starter
Joined: Nov 2016
Posts: 7,847
Likes: 3,498
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Turned out to be my dipstick had worked it’s way out a couple of inches and I was hearing noise from the crankcase. Surprised I didn’t get an emissions code.
