zblowfish

Hi Everybody,

I've been a frequent reader on these forums and have owned my E350 for 6 years now, currently 176k miles. One of the main points I researched prior to ownership were the balance shaft issues with the M272 engines (early). Prior to purchasing the car, I ensured the engine was a late model engine and built after those impacted that so many have had issues with. Didn't expect to have any "catastrophic" issues, but I do understand my car has 176k miles on it. My hope (wish...) has always been to take it to 300k, but a little worried about that at this point.

Anyway, enter today. My car has had intermittent CE light issues which clears after a few starts, scanner indicated the P2004 P0024 codes. I took my car into a new mechanic (my previous mechanic has retired). Resulted in worst case scenario, an intake manifold replacement due to flap being stuck open & new magnets all around (4 replaced), along with my Variable B service. Quite costly for a car at this age.

After the new mechanic performed the above service I drove it home (warm) without issue. The next day on my first cold start, the car misfired on multiple cylinders which has never happened to me before. Threw dozens of codes. I limped it back to them & they indicated it was a coil pack issue and replaced 2 coil packs. I was surprised that would happen the first cold start after this service...

The mechanic is now saying my car is throwing two new codes P0016 and P0017 (he indicated they are "hard codes" which I'm not sure what that is) after replacing the coilpacks/intake manifold/magnets which have never fired for me before. They believe it's due to a stretched timing chain due to the open flap on the intake manifold and oil getting inside the intake manifold over time and just due to the age of the vehicle at 176k miles. To me, I'm just surprised that none of these codes have fired before all of this service, and I was thinking most of these types of timing failures are due to the balance shaft sprocket issues from early gen engines.

Long story short, I'm planning to take the car home & look into the camshaft position centers myself. Does this (a car with 176k miles facing timing chain stretch) seem like the culprit to you all given this is just now firing after the service? Engine has always been serviced with Mercedes full synthetic oil at 10k interval, but it has been burning a bit more oil since the intake manifold issues discussed above.

Thank you!

nguyenphananh

you should find another mechanic. He is incompetent, and scamming you. All the misfired and codes happened after replacing the manifold were caused by the manifold gaskets were misaligned, folded during installation process, which cause vacuum leaked!!. For all the people who replaced the manifold themselves (including me) knew this very well!!. Due to the tight and difficult to reach location, the gaskets always felt off, and misplaced!!. He will have to remove the manifold and reinstall... all the issues will go away!!. Nothing wrong with your coild packs or timing chain!!. He is ripping you off....

cetialpha5

Ditto on the above. There's many threads on here about how hard it is to get the intake manifold gaskets to line up. When it's properly lined up, you won't see the gasket sticking out. Also there's lots of things to connect and disconnect when changing the intake. Like you need to lube the fuel injector O rings. Hope he got new ones and not reused the old ones. That can also lead to misfires. I had the intake changed on my car before and didn't have any issues. Actually I had one but we were able to find it right away, he missed one connector. Maybe he didn't hook up the camshaft position sensors afterwards. Also did he change the oil separator and the oil breather cover? Those tend to leak, the oil separator goes bad and oil gets into the intake which gums up the intake flaps. I think the breather on the right doesn't really go, just the one on the left and that one is reverse threaded so you turn it the opposite direction to tighten/loosen. You should check the other 3 plugs for leaks. I'm not really sure you need to change the hoses but they might be coated with oil from the oil separator going bad.

https://www.fcpeuro.com/products/mer...kit-oem-515810

zblowfish

Thank you both.

I got my car back today, and I have a strong feeling it's going to return to the shop. I agree it's super frustrating as this is one of the most reputable (and similarly expensive) shops in the area, they just turned over their lead Mercedes mechanic/owner and I am losing any trust that they still know what they are doing. CE light came on the way home, it's showing a P0024 code now. I've already paid them for ALL of these repairs and I'm almost to the point of going to a separate mechanic to check their work. Only thing holding me from doing that is cost of an extra person in the mix.

I would like to test the vacuum leak theory. I opened up the hood shortly after starting it cold and I could hear a hiss coming from the front side of the engine (intermittent, would hiss for 2 seconds, 1 second off, repeat). I am not familiar with how a vacuum leak sounds but have heard of methods around using brake cleaner/etc. to test.

zblowfish

Let it cool down for a bit, here is what I am thinking may be a vacuum leak. Doesn't sound like belt noise to me (but may be misunderstood):