Deleting my DPF on my 08 CDI
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Junior Member
Joined: Sep 2017
Posts: 34
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08 e320 Bluetec 200k miles
Deleting my DPF on my 08 CDI
Hey guys, my 08 E320CDI DPF is completely plugged and there's no easy way to clean it. I removed the whole exhaust system and tried but its completely plugged. The car runs great with no exhaust (although a little louder than normal). My question in general is has anyone ran their car without a DPF for any length of time and if so, any issues? There is no emissions in my area so no worries there. I get a couple of codes warning of unplausible differential pressure on the DPF but its not causing it to enter limp mode. It doesn't appear that the ECM is overly concerned with the DPF being gone. I'm thinking about having a pipe fabricated to replace the DPF instead of spending $1k to buy a new one on a car that's 16 years old. Any thoughts?
Junior Member
Joined: Nov 2024
Posts: 16
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From: Vienna
2013 CLS 350CDI; 2015 E 250CDI
I can say that I have seen cars that operated for years nicely without DPFs. There are "DPF off" procedures required on the software side also, it is not enough to simply remove the filter physically. Same is true for the EGR.
You need to find someone in your area who can program the filter out. In terms of the hardware, you can simply help yourself and brake the ceramic filling of the DPF out with a crowbar. The result should be the pipe you need
In case you decide to stick with the DPF, then instead of cleaning / replacing the DPF, I would recommend to first find the reason why the DPF is plugged. In most cases it is a leaking turbo that fills up the DPF.
Once the root cause was found and eliminated, you can replace the DPF.
You need to find someone in your area who can program the filter out. In terms of the hardware, you can simply help yourself and brake the ceramic filling of the DPF out with a crowbar. The result should be the pipe you need
In case you decide to stick with the DPF, then instead of cleaning / replacing the DPF, I would recommend to first find the reason why the DPF is plugged. In most cases it is a leaking turbo that fills up the DPF.
Once the root cause was found and eliminated, you can replace the DPF.
Thread Starter
Junior Member
Joined: Sep 2017
Posts: 34
Likes: 6
08 e320 Bluetec 200k miles
Thanks for the reply turbomint.
I've been running the car without exhaust for 5 days now and no real issues. It's not even that loud. I get a code indicating that the DeltaP is unrealistic (which I agree with) but its not causing any issues. I've been having a high back pressure code for a long time...and still do. I replaced it with a china sensor and its still showing 18psi with the sensor laying on top of the engine. I ordered a OEM one today. That's a good thought on breaking the media out of the DPF. I can't get to it on the inlet side because the pipe is long and curved. I CAN get to it from the outlet side. Will it break out from that end?
Regarding root cause - I suspect you are correct on the oil in the turbo. It's using a lot of oil. I replaced the Crankcase vent valve assembly 18 months ago and thought I had it solved but it seems to be back. I think I replaced it with a knockoff part also - can't remember. But... I gotta do something because its using a bunch of oil.
Regarding software updates on the ECM, I know what your saying... I had to do that on my truck but this vintage of Mercedes Bluetex doesn't seem to mind much. Of course there are things I may not know about that would create the need for this. Do you know what specific issues I will run into if I run it with no software modifications (other than codes)?
I've been running the car without exhaust for 5 days now and no real issues. It's not even that loud. I get a code indicating that the DeltaP is unrealistic (which I agree with) but its not causing any issues. I've been having a high back pressure code for a long time...and still do. I replaced it with a china sensor and its still showing 18psi with the sensor laying on top of the engine. I ordered a OEM one today. That's a good thought on breaking the media out of the DPF. I can't get to it on the inlet side because the pipe is long and curved. I CAN get to it from the outlet side. Will it break out from that end?
Regarding root cause - I suspect you are correct on the oil in the turbo. It's using a lot of oil. I replaced the Crankcase vent valve assembly 18 months ago and thought I had it solved but it seems to be back. I think I replaced it with a knockoff part also - can't remember. But... I gotta do something because its using a bunch of oil.
Regarding software updates on the ECM, I know what your saying... I had to do that on my truck but this vintage of Mercedes Bluetex doesn't seem to mind much. Of course there are things I may not know about that would create the need for this. Do you know what specific issues I will run into if I run it with no software modifications (other than codes)?
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Joined: Jan 2009
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From: V E G A S
1922 Ford Model T / no OBD
I had DPF deleted on 2014 Bluetec, in years when MB could not deliver replacement parts.
Car even with hollow DPF would pass annual NV sniff test on rolls, but white car had constant accumulation of soot on the rear, when I could not tell how much was on my lungs. I had ECU reprogrammed and showing DPF as "n/a" but NV did not plug OBD for smog test.
Taking advantage of Bluetec Settlement, I reversed the process and have clean car/clean lungs again.
I strongly advise to drive modern diesels with monitoring system like ScanGauge3. This way you can see the problem developing.
New DPF from forum sponsor sell in the range of $1000, what is far cry from $3000 I was quoted by MB.
Car even with hollow DPF would pass annual NV sniff test on rolls, but white car had constant accumulation of soot on the rear, when I could not tell how much was on my lungs. I had ECU reprogrammed and showing DPF as "n/a" but NV did not plug OBD for smog test.
Taking advantage of Bluetec Settlement, I reversed the process and have clean car/clean lungs again.
I strongly advise to drive modern diesels with monitoring system like ScanGauge3. This way you can see the problem developing.
New DPF from forum sponsor sell in the range of $1000, what is far cry from $3000 I was quoted by MB.
Junior Member
Joined: Nov 2024
Posts: 16
Likes: 6
From: Vienna
2013 CLS 350CDI; 2015 E 250CDI
Unfortunately the software DPF off doesn't cure the soot
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
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From: V E G A S
1922 Ford Model T / no OBD
To make it clear, I drove with DPF delete for about 3 years, recording each fill up on fuelly.
There is no recordable difference in mpg between periods of driving with DPF or hollow DPF.
I also could not notice any difference in the power, or throttle response.
The only difference was soot.
There is no recordable difference in mpg between periods of driving with DPF or hollow DPF.
I also could not notice any difference in the power, or throttle response.
The only difference was soot.
Newbie
Joined: Jan 2022
Posts: 6
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08 E320
Same car but with the bluetec
Reading between the lines: If MD is fine running without an exhaust, that makes it sound like I could just disconnect the sensors to solve my DPF problems.
Right now I am getting P242f at startup => drive some => limp mode => + codes P244b and P0299
The car (named Big Don, long story) has 170K miles and some other issues. Engine runs great. I don't want to spend too much money on it; I just want to drive it as far as it will go.
Reading between the lines: If MD is fine running without an exhaust, that makes it sound like I could just disconnect the sensors to solve my DPF problems.
Right now I am getting P242f at startup => drive some => limp mode => + codes P244b and P0299
The car (named Big Don, long story) has 170K miles and some other issues. Engine runs great. I don't want to spend too much money on it; I just want to drive it as far as it will go.
Last edited by wp-mb; Aug 6, 2025 at 04:46 PM. Reason: more
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MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
Same car but with the bluetec
Reading between the lines: If MD is fine running without an exhaust, that makes it sound like I could just disconnect the sensors to solve my DPF problems.
Right now I am getting P242f at startup => drive some => limp mode => + codes P244b and P0299
The car (named Big Don, long story) has 170K miles and some other issues. Engine runs great. I don't want to spend too much money on it; I just want to drive it as far as it will go.
Reading between the lines: If MD is fine running without an exhaust, that makes it sound like I could just disconnect the sensors to solve my DPF problems.
Right now I am getting P242f at startup => drive some => limp mode => + codes P244b and P0299
The car (named Big Don, long story) has 170K miles and some other issues. Engine runs great. I don't want to spend too much money on it; I just want to drive it as far as it will go.
Disconnecting the sensors will not prevent DPF from clogging, so even if your engine runs great now, it will not last.
As for Bluetec, they also have SCR aka DEF system, who is independent from DPF. When I had DPF delete, the SCR was still working, what made reversing the process much easier.
What is your DPF load showing now?
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MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,152
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From: Colorado
G550
Not sure where you are located, but in the U.S. tampering with any emissions control component is illegal. And if you're in a location where vehicles require emissions testing, a missing DPF will flag a failure. DPF equipped vehicles are supposed to have regeneration cycles that burn off the particulates to keep the DPF clear. If you install another DPF, you should have the system checked for proper operation.
