C400 Loss of Compression?
MBWorld Fanatic!
Joined: Feb 2016
Posts: 1,577
Likes: 264
From: Portland, OR
C450, GLC43
OK, I take it back. You may want to talk to a lawyer if you haven't already. I doubt it will get you far since CPO isn't covered by most Lemon Laws, but each has different buyer protections so... who knows?
You should try contacting MB Customer Care again. I never found them to be helpful but others on this forum have. You may get lucky.
You should try contacting MB Customer Care again. I never found them to be helpful but others on this forum have. You may get lucky.
Thread Starter
Junior Member
Joined: Aug 2017
Posts: 25
Likes: 1
From: Freeland, MI
2011 ML550, 2015 C400
Went to the dealer yesterday and requested they not touch it until I got there. The tech found no oil on the dipstick, put a quart in it, still nothing on the dipstick. Had them extract all the oil and about 6 quarts came out, so there was roughly 5 quarts in the car at the time it was shut down. Not terribly low, capacity is 6.9 quarts, but my concern is that it appears the leak is coming from the camshaft area on the new cylinder head. The dealer is still investigating, but I'm trying to decide what, if anything, I should demand replaced due to oil starvation. Dropping 2+ quarts in roughly 70 miles of driving seems pretty severe and something had to be starved.
Thread Starter
Junior Member
Joined: Aug 2017
Posts: 25
Likes: 1
From: Freeland, MI
2011 ML550, 2015 C400
Dealer diagnosed it as a "blown out freeze plug" in the new cylinder head. I noticed several new plastic covers and turbo heat shields that were never put back on when the car was twice returned without them. So far so good, as the original complaint of the car shaking at idle is no longer present, it's not leaking boost, and doesn't appear to have an oil leak, either.
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,999
Likes: 1,352
From: Cincinnati
2010 E350 4Matic
Thank you for taking us on this journey with you. This really reflects poorly on Mercedes in so many ways to the point that I as a life long Mercedes fanboy am telling myself as much as I like these cars I would be foolish to buy another one. I am glad that you had CPO coverage and I hope Mercedes lost their *** in the expense of the repair. This is 2019 it's not like this is new technology.
Last edited by MBNUT1; Nov 16, 2019 at 04:50 PM.
