I just had a engine failure (locked) on Tuesday, and awaiting what happened

14 days ago I took my car for the MB dealership service in North NJ to fix the vacuum door lock, and inspect the transmission that was a bit jerky on low speed. They did a 5mls road test, but was unable to find anything. Instead they fixed the door lock, also did the recall (2018070015 and replaced the dipstick of active curve system). The dealer also recommended to;
1. Change the transfer case input shaft seal (removed lower engine panels, detached drive shaft, removed cross memeber, removed transfer case and replaced input shaft seal).
2. Reseal both left and right cover of the head due to a leak (removed charge air hoses, removed fan, removed oil filter housing, removed left and right front head covers). Cleaned and resealed head covers, CAM SOLENOIDS and oil filter housing.
Total: $3,841

When I picked the car at closing time, I noticed misfire. The service guy was gone, and I stopped and restarted the car about 3-4 times after-which the misfire was gone. Thought it needed some "learning to reset". Next day another service rep called for courtesy follow up, and I mentioned the problems, and she said she will left a note to the rep for follow up, which never happened. I then drove the car about 14 days, 140mls, running normal. Got message on the morning to add 1QT of oil (maybe because of the service they did), added the oil, and headed to work, this Tuesday driving about 40-50mls/h the engine shut off itself after 30min of driving, and had the car towed to the same MB dealership.

The engine had codes for P0368, PO343, PO392, PO347 (camshaft position), and also PO106 (manifold absolute pressure).

Yesterday the rep called, and said "Bad news, the chain is not moving, and that they have to pull out the engine, which will cost $2,145 out of my pocket, so they can investigate first what is wrong". The rep stated it could be time-chain sprocket or Balance shaft went bad, that "these M157 engines are known to have those problems". Does this sound right?

I was reading about the CAM SOLENOIDS which they cleaned that
"As part of the variable valve timing (VVT) system, the camshaft adjuster solenoid is responsible for allowing oil to adequately flow through the VVT system upon it’s engagement. The VVT system engages to deliver extra power to the vehicle when it’s traveling under added stress, such as when it is carrying a larger, heavier load, or when traveling uphill. Since the solenoid is necessary in order to allow oil to lubricate the timing chain and gears, if oil cannot reach these parts then too much friction can cause them to wear out quickly. This can lead to engine failure and expensive repairs."

Could it be he miss-installed, or damage the solenoids as they took them out? The car was running fine before, but if the sprocket is damaged, they claim a poor known design from AMG, not the lubrication that might happened.


Anyone else experienced anything similar? Will update the post when I hear more....