2010 W204 C250 CDI (OM651) Intake Leak

[Johnny5C]

Hi first post - be gentle!

After a particularly "spirited", uphill, overtaking manoeuvre I got the EML light up with P2279 code. I cleared it, but it comes back after a bit of driving.

After a bit of googling and waiting for the weather to improve I've just got round to taking off the boost pipes to inspect them and they don't have any visible splits that I can see. (see photo)

The pipe coming out of the turbo has a fair bit if oil around the union at the turbo end (see photo), and I would consider the pipe a "sloppy" fit. None of the pipe unions are particularly tight IMHO.

I suppose now I'm looking at the intake manifold right? Is there any other common places for a boost leak?

Sure, I could take the car to garage for a smoke test - but I'm a tight bugger, and perhaps more importantly, my wife would judge me!.

Is there a chance the leaky pipe is not visible to the eyeball? any other test methods? Washing up liquid?

There is fair amount of oil on the engine up where the plastic intake pipe (after the intercooler pipe) heads up into the engine bay to the intake. (photo attached)

I can imaging replacing the intake manifold is a right PITA - but I don't mind getting out the tools and doing the work myself, providing I have a decent DIY guide.
Does one exist? Is it a DIY job?

I got the car 6 months ago, and up to this point it drove like new, although I did have to do the DPF pressure sensor just after I bought it. Its done 190k miles and a huge stack of servicing paperwork.

(and, the small print, in the interests of putting the full picture across, I also have P2463 code pending - ive been driving around with the car in "limp mode" for a while, and I think I've clogged, or getting close to maxing out the DPF. While this was going on the pedal position sensor was putting up a code. (My OBD scanner was playing up and I assumed the EML was boost related for about 3 weeks- once I got the OBD working again I saw the pedal sensor issue and fixed it)).
Once I get the boost leak sorted I will address the DPF, either a forged regen, or a manual clean out, or both. I guess all that time with the EML on the car was unable to to a regen.

Cheers!

 

[Johnny5C]

Well, it's in tomorrow for a smoke test. Still have hope it's a simple fix, not the intake manifold.

 

[Johnny5C]

OK - i've just got it back from my local garage (not merc indy). They did a thorough smoke test and could not see any intake leaks.

Their thoughts were a potential blocked flap or actuator in the intake?

"Code read system to find fault on boost pressure and throttle body (air shutoff flap). Potentially blocked with carbon but further testing required."


The EML light is still on (with bluetooth dongle and Torque app) - P2279 - Powertrain - Air intake System Leak

with pending P2463 - Powertrain.

I can clear it, but it comes immediately back on. (is there a sure fire method to clear the codes? I'm not convinced i'm doing it right)
(Ignition pos 2, engine off, read code, clear code, start engine)

I suppose my next step is the indy to see if they can see any more info with STAR, and maybe look at the real time data?

Any thoughts or input is appreciated.

 

[Johnny5C]

Would a duff boost pressure sensor throw this code on a car with no intake leak?

The sensor (or a pair) are cheaper than a diagnosis at my indy..

 

[mersum1es]

It compares pressure readings and MAF reading according all parameters (pressure demand, injection etc.). What your pressure sesnor are reading when engine is not running? You have twin turbo, are actuators checked? Actuator arm moves, vacuum lines ok...?
Boost fault can be anything from intake to cylinder, needs overall check (like you have done), live data reading, and finally component tests at 'high end' diagnostic device, SDS preferred.

 

[Johnny5C]

OK, so I took it to my local indi for some further diagnosis. They think it's a throttle valve fault, and recommended replacing it before they can do any more intake leak testing. (it previously had a smoke test, with no leak)

So, is this a driveway DIY job? can it be accessed from underneath?
Ive done some pretty grim engine work before, but had decent guides to follow.

FYI the complete codes from Xentry are:
P012300 Position sensor 1 for throttle valve has short circuit to positive. (wiring, or a syptom of a duff TV?)
P246397 The soot content of the DPF is not OK. (The DPF is grumbling because it cannot do a regen?)
P211271 The throttle valve is jammed closed. The actuator is blocked (Jammed, so it is a mechanical issue - soot build-up?)
P227985 A leak was detected in the intake air system. There is a signal above the permissible limit.

Of course, my worry here is that I do the throttle valve myself, or pay £650+ for the indi to do it, and THEN I discover the intake manifold is cracked.
Fingers crossed the smoke test eliminated leaky intake manifold.

Ive also added some data from Xentry in the attached pic.

 

[Eddiemc11]

Hi johnny
How are u getting on with it?

 

[Spyros777]

Hello Johny, my intake manifold was leaking from the side and it was visible because it had some oil coming off of it.

Had a quite similar problem where the STAR was reading high and low boost at the same time. After some trial and error it was the turbo actuator and the inlet charge pipe. Replaced as well the intake manifold as it was time to be replaced due to the leak which was making a mess in the engine bay.

Maybe your guy can test fit a throttle valve on the spot (maybe he has one there?) just to narrow it down?

 

[Johnny5C]

I don't think it is possible to test fit a throttle valve. The indi wanted 4 hours to do the work, so I'm presuming getting it off is a 2 hour job.
In all honesty, I was hoping for some guidance from this forum on the complexity of the job, to see if I can tackle it myself.

 

[Johnny5C]

Just to follow up. I had the throttle valve replaced at £700 three weeks ago, and after the first 70mph cruise on the motorway last week the car went back into limp mode. Took it back to the indy who diagnosed a defective intake manifold. Another 1200 to spend.
Not sure how I feel about it. The car seems to be leaving an oil trail, so possibly suffering from a leaky old filter manifold leak. Is it really woth investing another 1200 into an engine that is on the way out at 191000 miles?

 

[FlorinM]

Hi @Johnny5C

Based on what you shared here on the forum, they car will need a bit more than just the 1200 for the intake manifold, you were mentioning the DPF needing some attention and the noticeable oil leaks. All that work done at an indy probably is about the value of the car.

It really depends how much you still want the car, if you are in a position to exchange it for something more reliable. In the current market in can be hard to find relatively reliable and comfortable cars under 3-4k.

Looking forward to an update from you!