Tjmcstay

Hello everyone,
i have a c450 that recently threw a nasty CEL accompanied by misfires in cylinders 4,5, and 6. Took it to a local shop, closest one i could find and trust and they’re telling me the motor is blown. They found those three cylinders soaked in oil with a borescope but didnt mess with it beyond that. Considering it only has 55,000 miles on it im really skeptical (or im in denial)
Was last taken for service in July at an mb dealer.

Anyone have any experience with something like this? Any recommendations? Really praying its not blown, only owned it for about a year now.

thanks for any help!

waisoserious

Is your car modded? What Mods do you have?

Tjmcstay

Just the rv 3.1 tune from amr. Its been about a year since. Had plans for downpipes but never got around to it. Literally just dropped a pretty penny on a tcu tune from amr as well. Arrived in the mail 2 days after it blew 😑😑😑

spoke to amr about it and their amg tech has suspicions on a defective pcv or defective oil sump system

CarHopper

The shop said it was blown. What other advice are you looking for here? If you're skeptical have it towed to another shop for a second opinion.

Have plenty of whiskey nearby for when the denial wears off -- that's the best advice I can give.

waisoserious

It sounds like whatever the problem is, you only have the option of seeing the dealer.

chassis

What does blown mean? Does it have compression? Can the engine be started?

Oil in the cylinder can come from:

- crankcase (failed rings, piston or cylinder wall)
- cylinder head (failed valve guides)
- oil gallery (failed cylinder head gasket).

If the diagnosis is correct, that three cylinders on the same bank have oil in them, it sounds like a gross failure of the cylinder head gasket. What would cause that? How does a failed PCV or sump cause the same symptom on three cylinders of the same bank?

Tjmcstay

Not too many details from the shop besides the oil in cylinders and plugs. Attached notes.
But she still starts, runs without stalling. Just feels like im sitting inside an earthquake lol.

This is exactly where im at. Its really odd that its all the same bank which makes me think its a gasket. Really curious though what caused it.
A month or two ago i got a check oil message, so I checked it and it seemed low so I topped it off with a quart. From what i know these engines eat oil, so chalked it up to that and was fine after. But itd be a stretch imo for one quart over to blow like that. Hopefully taking it to a euro shop next week. Wish me luck

mau108

Based on 3 cylinders having oil in them and misfiring it doesn't sound like a blown engine. Again like others have said you need to take it to a proper shop to get it diagnosed (this is why I tuned my car with a local shop that will back their product and have the proper techs to diagnose the car). Also I don't buy what AMR is stating either. Typical move the blame away from them move.

chassis

@Tjmcstay What are your DIY skills? The service writeup is unacceptably vague. "Soaked"? With what? Oil or gasoline or coolant?

Do you smell gasoline?
Do you smell oil?
Do you see visual oil leaks?
Do you see visual coolant leaks?
Are you losing coolant? Check the reservoir.
Are you losing oil? Do you have a dipstick or are you able to measure oil level with the MFD?
Do you have smoke, mist or vapor coming from the tailpipe? If yes, what does it smell like?

The word "blown" is not specific enough. Blown could be from failed pistons/rings/cylinder wall, head gasket or valve/valve guides.

Have you measured compression on the driver's bank?

CarHopper

I know amr is a sensitive subject on this forum but as soon as I saw the OP was tuned by them along with their response to this I just sighed and felt for him. Waiting to see what a competent shop says about the OP's engine.

waisoserious

Just take it back to AMR and ask their """""AMG Tech"""""

Tjmcstay

Got results back from the shop, sigh. Cracked piston ring. Got the option of walking away, a used engine w 45k miles, or a brand new one. Tempted to go with used one but not sure if i want to be underwater slightly with no car or deep underwater with a car. Ill take that whiskey now

C43HeartBoost

I am not sure on the availability of OEM pistons, but if the cylinder wall is not too badly scored, a light honing and a new piston should be sufficient. If not, I vote for a used short block - as you do not need a full long block if the only damage was a cracked ring.

What price were you quoted for the used engine?

Tjmcstay

The damage is pretty bad, unfortunately i think itd be more than a light honing.





They’re quoting me out the door taxes and all at 13,800

C43HeartBoost

Did they give you a breakdown of parts versus labor?

mo11

Wow! A few $ K’s more and you can get a c63 engine...

waisoserious

Any feedback on what would cause a cracked piston ring?

CarHopper

Maybe AMRs AMG mechanic and top tier customer service can chime in.

hc_416

he is really tuned by AMR? Also what are tbe mods to the car? Running e30 etc?

CarHopper

According to post 3. Says was going to down pipe and just got tcu tune so this being a complete guess I would assume this car only has the 3.1 amr tune.

And according to other threads this isnt the first time one of these cars lost a motor with an amr tune on it.

Unfortunately its essentially impossible to point the finger directly at any one thing with a failure like this. According to one "AMG technician" out there it could have been a bad PCV valve. If I had to guess it was the result of high boost, high heat, and insufficient cooling.

hc_416

Is saying that blow by is the reason the engine blew...... doesnt even make sense lol was there any damage on the top of the pistons at all?

CarHopper

I'd love to see what the top of the piston looks like. Also, did they just scope 1 cylinder? Or look at the others as well?

chassis

Possibilities:

- excessive combustion pressure
- misfire/detonation
- excessive temperature
- fatigue caused by repeated exposure to the above

C43HeartBoost

My vote is #2 exacerbated by #4.

Tjmcstay

nah, nothing like that. Im sure they would give me the info if i asked but made the decision today to cut my losses and sell it, numbers just didnt work out unfortunately.