Oil dilution issue on GLC 300de (OM654 hybrid diesel) – engine broken!
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Newbie
Joined: Aug 2025
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GLC 300 DE
Oil dilution issue on GLC 300de (OM654 hybrid diesel) – engine broken!
Hi everyone,
I own a 2021 GLC 300de (OM654) with 89,000 km, about 34,000 km in EV mode. We mostly drive short city trips, so the diesel engine rarely warms up fully.
Recently the car lost power, showed vibrations, and needed two injectors replaced. The issue remains and the garage now suggests a complete engine replacement. The mechanic also noticed the engine oil looks abnormal, so we’re having it analyzed.
From my research, this could be severe diesel fuel dilution in the oil.
Has anyone else with a GLC 300de (X253 or X254) experienced similar problems?
Thanks in advance for your insights!
I own a 2021 GLC 300de (OM654) with 89,000 km, about 34,000 km in EV mode. We mostly drive short city trips, so the diesel engine rarely warms up fully.
Recently the car lost power, showed vibrations, and needed two injectors replaced. The issue remains and the garage now suggests a complete engine replacement. The mechanic also noticed the engine oil looks abnormal, so we’re having it analyzed.
From my research, this could be severe diesel fuel dilution in the oil.
Has anyone else with a GLC 300de (X253 or X254) experienced similar problems?
Thanks in advance for your insights!
Senior Member
Joined: Apr 2023
Posts: 470
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2014 S63 2010 ML350 Bluetec 2009 SL550
You do NOT want a diesel for this use case. They NEED to get warmed up and really benefit from a few hours of regular highway use weekly.
Gas motors will tolerate what you are doing much better than a diesel.
Gas motors will tolerate what you are doing much better than a diesel.
Thread Starter
Newbie
Joined: Aug 2025
Posts: 3
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GLC 300 DE
Indeed, this is what I realize now - however, the Mercedes dealer never mentioned such use case restriction nor the purchase order...
On the contrary, I believe that we used the car for what it is supposed to do: 30 km electric autonomy = perfect for short trips in the city
MBWorld Fanatic!
Joined: Apr 2016
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From: Ireland
GLC 300d 4matic
Thks for the feedback -
Indeed, this is what I realize now - however, the Mercedes dealer never mentioned such use case restriction nor the purchase order...
On the contrary, I believe that we used the car for what it is supposed to do: 30 km electric autonomy = perfect for short trips in the city
Indeed, this is what I realize now - however, the Mercedes dealer never mentioned such use case restriction nor the purchase order...
On the contrary, I believe that we used the car for what it is supposed to do: 30 km electric autonomy = perfect for short trips in the city
