W204 250 CDI - banging sound after the excessive tightening of fasteners on the plastic sump

[Talentrews]

Greetings to everyone,
I own a 2010 W204 250 CDI (OM651) equipped with a plastic oil sump. I recently had an oil leak from the sump gasket, therefore I attempted to tighten the sump nuts; however, I did not use a torque wrench, likely resulting in overtightening.


Following the tightening, the leak ceased; nevertheless, the engine now produces a pronounced knocking or ticking noise that accelerates with the rpm. The oil level is enough; nevertheless, I am concerned that I may have compressed the gasket, perhaps causing fragments to dislodge and obstruct the oil collection. Perhaps the sump is distorted or improperly positioned? Alternatively, it may be a coincidence that the engine failed simultaneously.

The garage I visited reported that a component had detached and penetrated the engine. The engine is likely irreparably damaged and requires replacement. I had only drove it a short distance, about two minutes to the garage.

It is necessary to elevate the engine in order to extract the sump, hence I am uncertain about the appropriate course of action. Ought I to relinquish my efforts? Alternatively, get a lift and attempt to replace the sump and gasket.

[Talentrews]

https://www.youtube.com/watch?v=5EGx-bIdIK8

[Bedelon]

That seems rather unfavourable; nonetheless, I find it difficult to accept that only tightening the sump bolts could result in such an outcome, regardless of the degree of tightness applied. I am not fond of coincidences; yet, it seems to be one to me. However, without a detailed examination and precise identification of the noise's source, it might be attributed to other factors.

[Lemmand]

Could you have disrupted anything else?
Is it possible that the air filter is loose and vibrating?
As said without being present? However, it does not resemble a banging engine.

[Micobe]

It does not seem metallic to me either.

[Liveek]

Resembles the sound of plastic being struck, reverberating like to a drumhead.

[Adv3nture]

Regrettably, the only definitive method to ascertain the situation is to remove the sump.

[Micobe]

If, and only if, the engine is consuming itself, there will be metallic particles present in the oil. Potentially observable to the naked eye, unequivocally ascertainable with oil analysis.

Enquiring about the proximity of the sump to moving mechanical components. Proximate enough that excessive tightening has caused them to make contact?

[Talentrews]

Thank you for all the responses. I was also astonished that the engine could be so simply damaged.


I was apprehensive about doing it, but I will ascertain the source of the noise. I may get a lift and remove the sump, since I have nothing to lose.

It is possible that the sump has deformed, causing an object to make contact with it. I would have expected the garage to discern the source of the noise.

This is its appearance:

[Talentrews]

[Micobe]

If that is occurring, it should be feasible to discern with your fingertips the location of the impact inside the sump, provided you can sufficiently reach the sump.
Only proceed if the sounds is not metallic. Should it be metallic, the likelihood of engine damage is significantly increased. Moreover, it is likely that nothing is impacting the plastic sump.