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SuperRed

Fed up with diesels.

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Had diesels now for a good number of years and had DPF issues with several of them. Last Monday the engine management light came on. Booked the car in to have it looked at by an Indy Mercedes company. The error was the DPF was 110% full and it had 14 failed regenerations. I advised them that on the Saturday we drove 125 miles non stop mainly on motorway and the reverse journey on the Sunday, then on Monday the EML came on so I am struggling to understand why the DPF had not regenerated. They had no answer. £200 later, I was driving home. Very frustrated. I have had the car just 2 years and my driving distances etc has not changed one bit, so I am thinking the car has some other issue but I was told the only issue in the fault log was the DPF over full and the failed regenerations. :angry:

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1 minute ago, onewheelonmywagon said:

Sounds like you need a second opinion.

You may well be right. I will see how it gets on and if the error shows again I may well have to take it to a main dealer (stealer).

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Sounds like you are complaining about the wrong thing.

Its Mercedes cars, you should be complaining about, not diesels in general.

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2 minutes ago, daveat92 said:

Sounds like you are complaining about the wrong thing.

Its Mercedes cars, you should be complaining about, not diesels in general.

Maybe, but I have had issues with Nissan and BMW DPFs as well.

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£200 is a bargain!  Did they renew the DPF or clean it?

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4 minutes ago, SuperRed said:

Maybe, but I have had issues with Nissan and BMW DPFs as well.

I have a diesel and don't even know what a DPF is !

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All from new

Citroen Picasso Grand diesel old shape

Ditto new model

Ford Galaxy

Now two years with Seat Alhambra.

All diesels.

Total mileage 120000 miles to date.

No DPF problems.

My neighbour jet washed his £50000 Mercedes and washed the paint off!!

Turned out it was damaged at the factory and repaired.

Perhaps Mercedes are being run by accountants again?

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3 minutes ago, SuperRed said:

Maybe, but I have had issues with Nissan and BMW DPFs as well.

 

So what is your vehicle usage pattern? Many journeys that don't result in 20 minutes of quite sustained driving above 45 mph, after due time to get well warmed up?

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I am surprised you got a Merc DPF replaced for £200. You haven't mentioned the age and mileage of the Merc. To have failed 14 times it must have been faulty for a long time - quite likely before the last service, so why didn't the service reveal that code?  Was the service carried out by a Merc workshop, and did the service include a diagnostic check because a Mercedes service should have. I had my Volvo serviced by an inde' for a couple of years and they messed up and it cost me a heap of money and never got sorted properly, so I went back to the Volvo workshop where they diagnosed differently to the inde' It wasn't a complicated matter but the inde' had got it all wrong. I found there wasn't that much difference in the service cost either because the inde' charged a lower rate but booked more time.

Edited by Ern

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Tug is a Merc 350 Coupe Diesel and touch wood no issues... Great Tug. My auld 2.7d Jag now that was a different story ... 

 

GAS ...

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What did they do for £200?
 

Could be a faulty sensor in the regeneration system, this is usually why a regen won’t perform even if you’ve done a long trip

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33 minutes ago, Ern said:

I am surprised you got a Merc DPF replaced for £200. You haven't mentioned the age and mileage of the Merc. To have failed 14 times it must have been faulty for a long time - quite likely before the last service, so why didn't the service reveal that code?  Was the service carried out by a Merc workshop, and did the service include a diagnostic check because a Mercedes service should have. I had my Volvo serviced by an inde' for a couple of years and they messed up and it cost me a heap of money and never got sorted properly, so I went back to the Volvo workshop where they diagnosed differently to the inde' It wasn't a complicated matter but the inde' had got it all wrong. I found there wasn't that much difference in the service cost either because the indie charged a lower rate but booked more time.

The DPF wasn't replaced. There was a charge for the investigation to find the issue and a charge for the forced regeneration. The last service was June and was done by the Main Dealer. The car is 2015 with 41K. Don't know if a diagnostic check was done on the service.

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14 minutes ago, FrankBullet said:

What did they do for £200?
 

Could be a faulty sensor in the regeneration system, this is usually why a regen won’t perform even if you’ve done a long trip

THIS.... I have a C250CDI with 60k miles and 6 years old now. Does a mixture of runs including short runs. Only time I had a DPF related sensor fail was when the exhaust back pressure sensor was faulty which was preventing the DPF regen as it didn’t know the current values. £50 and new sensor later not had a problem, that was a year ago. Mercedes and Volvo are both known to have rock solid DPF filters in the mechanical sense, and are better than the rest. The problem is nearly always a sensor downstream of the EGR failing. For £200 that would be around £90 for a diagnostic fault reading on STAR machine and then about £100 for a forced regen which would take 40-60 mins plugged into STAR. 

1 minute ago, SuperRed said:

The DPF wasn't replaced. There was a charge for the investigation to find the issue and a charge for the forced regeneration. The last service was June and was done by the Main Dealer. The car is 2015 with 41K. Don't know if a diagnostic check was done on the service.

Haha you got there first by 2 seconds 

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16 minutes ago, FrankBullet said:

What did they do for £200?
 

Could be a faulty sensor in the regeneration system, this is usually why a regen won’t perform even if you’ve done a long trip

They did mention about changing the DPF differential pressure switch but it was not showing as a fault so it was my choice.

 

My understanding is that it tried to regenerate but failed 14 times.

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With that info in mind and with how cheap and easy the exhaust back pressure sensor is to replace I would try it. If the error code on star is P0471 get it changed! Are they using STAR or is it a general diagnostic tool? If not STAR then shooting in the dark really!

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47 minutes ago, Pembssurfer said:

With that info in mind and with how cheap and easy the exhaust back pressure sensor is to replace I would try it. If the error code on star is P0471 get it changed! Are they using STAR or is it a general diagnostic tool? If not STAR then shooting in the dark really!

I don't actually know what they are using but they advertise as having full main dealer services so assume it would be the Star.

 

It's the second time I have used them and they do seem OK. Their reviews seem pretty good too. I was talking to an elderly gentleman in the waiting area who has been using them since they started up, (14 years ago I think he said) with many of the staff coming from a main dealer that had just closed down. He travels about an hour each way to use them and is very happy with the service he gets.

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2 hours ago, Pembssurfer said:

THIS.... I have a C250CDI with 60k miles and 6 years old now. Does a mixture of runs including short runs. Only time I had a DPF related sensor fail was when the exhaust back pressure sensor was faulty which was preventing the DPF regen as it didn’t know the current values. £50 and new sensor later not had a problem, that was a year ago. Mercedes and Volvo are both known to have rock solid DPF filters in the mechanical sense, and are better than the rest. The problem is nearly always a sensor downstream of the EGR failing. For £200 that would be around £90 for a diagnostic fault reading on STAR machine and then about £100 for a forced regen which would take 40-60 mins plugged into STAR. 

Haha you got there first by 2 seconds 

 

But isn't all this regen problem the result of the 2015 intro of Euro 6 diesels (tougher limits) with many cars not producing enough heat to perform the regen?

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2 hours ago, SamD said:

 

But isn't all this regen problem the result of the 2015 intro of Euro 6 diesels (tougher limits) with many cars not producing enough heat to perform the regen?

 

Automatics seem to suffer from not getting hot as they usually rev under 2000 rpm .

 

 

Dave

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Would running at under 2000 rpm really cause the temperature of the exhaust into the DPF to be any cooler than running above 2000 rpm? The power needed would be exactly the same, so the fuel burnt much the same, but running at higher revs will cause a greater air pumping most probably lowering the exhaust temperatures.  I feel running that power at a higher torque could well mean a higher exhaust temperature, than would be the case reving too much.

 

The use of DPFs well preceded the adoption of Euro 6, few engines could meet the Jan 2011 Euro 5 without it, so the switch came generally from Euro 4 to 5. not 5 to 6.

 

I many cases IMO the DPF was not physically tight enough after the exhaust from the engine so wasting some of the heat leaving the turbo. What now appears to be the case is very tight packaging of the turbo and DPF aft of the cylinder head to try and retain all the heat it can, as opposed to some earlier designs where the DPF was retrospectively introduced some way under the vehicle where space in an established design could be found, now it is designed to be where it should be.

 

IMO, if going the diesel route your usage needs to ensure there are frequent runs of the right characteristic  where the cleaning of it can take place.

Long enough to get to its initiation temperature, then sustained long enough and "loaded" enough for the full burn to be undertaken.

If you watch the fuel consumption you can sometimes note the drop indicating a burn has been initiated, then it is better to keep going in both duration and loading till it is completely done.

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When a regen is in progress extra fuel is dumped into the exhaust to heat up the DPF, my Range Rover elevates the temperature from the normal 180 - 220 deg C to 650 deg C + The soot level falls from the 20 - 25g down to 3g over about 5 or so minutes.

 

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1 hour ago, JTQ said:

Would running at under 2000 rpm really cause the temperature of the exhaust into the DPF to be any cooler than running above 2000 rpm? The power needed would be exactly the same, so the fuel burnt much the same, but running at higher revs will cause a greater air pumping most probably lowering the exhaust temperatures.  I feel running that power at a higher torque could well mean a higher exhaust temperature, than would be the case reving too much.

 

The use of DPFs well preceded the adoption of Euro 6, few engines could meet the Jan 2011 Euro 5 without it, so the switch came generally from Euro 4 to 5. not 5 to 6.

 

I many cases IMO the DPF was not physically tight enough after the exhaust from the engine so wasting some of the heat leaving the turbo. What now appears to be the case is very tight packaging of the turbo and DPF aft of the cylinder head to try and retain all the heat it can, as opposed to some earlier designs where the DPF was retrospectively introduced some way under the vehicle where space in an established design could be found, now it is designed to be where it should be.

 

IMO, if going the diesel route your usage needs to ensure there are frequent runs of the right characteristic  where the cleaning of it can take place.

Long enough to get to its initiation temperature, then sustained long enough and "loaded" enough for the full burn to be undertaken.

If you watch the fuel consumption you can sometimes note the drop indicating a burn has been initiated, then it is better to keep going in both duration and loading till it is completely done.

 

In the well documented case of JLR vehicles is is certainly Euro 5 to 6 not earlier when to meet those standards, there were layout issues affecting the proximity of the heat source to the engine.  These affected MY 2016 onwards.

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Then buy a petrol while you still can.

Pretty soon we'll all be on electric or hydrogen if the weirdy beardies get their way.

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15 minutes ago, SamD said:

 

In the well documented case of JLR vehicles is is certainly Euro 5 to 6 not earlier when to meet those standards, there were layout issues affecting the proximity of the heat source to the engine.  These affected MY 2016 onwards.

 

Except their Discovery 4 adopted it for the introduction of the three litre Euro 5 diesel engine MY 2011.

 

They had to introduce an Adblue system to achieve Euro 6, [MY2016] but that was for the stricter NOx control they could not meet via EGRs, not the particulate control the DPF addresses.

 

 

 

 

 

Edited by JTQ

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It would be interesting to know what fuel the op is using. Supermarket or branded.

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