Mercedes S Klasse Diesel Reduced Engine Power and Smoke

That sounds frustrating I had a similar issue with my S Klasse diesel a while back Engine light came on, it felt like I was towing a boat and fuel consumption went through the roof It was indeed the diesel filter In my case it was completely clogged up I tried some DPF cleaning additives but they didn't really do much It's like trying to unclog a drain with a toothpick You mentioned smoke Have you noticed what color it is Is it black white or blueish

Thanks for the quick response The smoke is blackish I haven't tried any additives yet but it sounds like they might not be a magic bullet Did you end up needing a complete filter replacement How much did that cost roughly

Black smoke is usually a sign of unburnt fuel which points even more towards a DPF issue Additives are like a band-aid on a broken leg in this case Yes I had to get the filter replaced eventually Honestly after all the messing about with additives I wish I'd just gone straight to the workshop and saved myself the time and hassle They have the proper diagnostic tools to confirm it's the DPF and can advise on the best course of action cleaning versus replacement

Okay that's really helpful I appreciate you sharing your experience Sounds like a trip to the workshop is unavoidable I'll get it checked out and probably end up with a filter replacement as you did I took it to the mechanic and you were spot on It was the DPF Needed a full filter replacement Cost me about 1550€ but at least it's running smoothly again Thanks again for your help