Hi All

I have a high mileage,460k, w212 e250cdi that i use for a chauffeur service in Australia.

A few months ago driving home, i felt a lil bump from the engine resulting with lose of power eml and limp mode, could drive home but had to manually change gears.

Previously had the boost hose split with exact same symptoms and so thought it was that and could restart car and not load it enough to trigger limp mode.

That didn't work so took it to mech, scanned it and returned maf code and gearbox code.

Cleaned maf, no result, changed maf, not oem but vemio, no result.

Ill cut the story short and say that we're basically throwing darts, replaced maf, other intake sensor, egr valve/cooler, 1 intercooler hose, intake manifold and this week pcv cover.

Car idles fine with no noticeable different sounds though i did notice a different smell after the long drive in limp, dpf level was low at scan and new maf was recalibrated.

Basically have changed all know air leak problems the om651 can have and mech says all data is within specs when driven.

so if anyone has any idea of something left field that could be causing this leak or a similar solved scenario i would greatly appreciate the suggestions.

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you're looking for an air leak on a half million mile diesel.
You've replaced many parts including the PCV cover only.
How are the compression test and cylinder inspection?

I don't suppose you want to invest a lot more parts before retiring this vehicle.... What happens if you feed it better oil viscosity?
Low mileage GDI engine respond remarkably well to it.

 

What's the current fault code?

 

Well other factors are hindering updating the car at the moment, but having changed most of the common components it would make sense to try and fix the car and run it for a few months before retiring her.
compression was and cylinder test were fine, though 1 injector had to be replaced after being removed.

 

p227906

 

I suppose that you retrieve the fault code with a generic scanner, it's not quite common for om651

The most common situations for untraceable leaks are sheered bolt from intake manifold or even on exhaust manifold

 

Well intake was replaced with no effect

have previously replaced the temp senser on exhaust manifold but how would it E.M create a air leak code?

 

Sometimes, because of bolt loose, the EM can be bent and a space will appear at the back side.

If you can find a Xentry system, you can start an automated leak test from where throttle, EGR, MAF will be actuated in such a way as you may understand from where the leak is built

Also, sometimes at the air filter case, ECU on air filter cover or even the air filter can produce leakage

 

but would a smoke test show a leak at the EM?

Mech has 3 different scanners, not sure if xentry though.

Reg filter case etc thats before the Maf so should affect air reading!!!

 

Car was running like new before the air leak occurred.
i alternate oils between 5/30 and 5/40 through the seasons.

 

Over the EM should be enough smoke to be noticed if is bent.

Indeed, Air filter case, ECU sealing, is after the MAF and could affect the air readings

 

I believe theyre before the MAF.

 

Sorry, before....but calibration of MAF is related with the pressure sensor downstream of air filter, and this is related with the tightness of the air filter case. Sometimes ( rare and hard to do it...) the connector from sensor downstream of air filter can be misplaced with another one nearby.

 

Quick update,

Mech rang and is 95% sure that the turbos are the cause for the air leak!!

From what i could understand at the time, as the mech was quite excited so don't quote me, but they smoke tested the actual turbo and said there was smoke leaking into the engine when technically it shouldn't due to this particular failure.

Sorry bout the ****e description, but the mech also mentioned he has never seen this "scenario" before but is going to video the problem and the solution and i will upload hopefully end of next week.

Cheers