Diesel MOT Nightmare

cedez

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270CDI 2004
Hi All

I do hope i am in the correct place in this forum apologies if i have posted in the wrong section.

Last year i failed the mot test at the council testing station because of the government emissions requirements for diesel cars. On my car door it shows the Plate value as 0.90 1/m drift value 0.08 1/m for my C Class 270CDI 2004 diesel estate

I was told that I need to get the engine red hot before putting it in for testing (i had only driven short journeys prior to testing unbeknown to me that i needed to thrash my pride and joy ) and put a whole bottle load from Diesel Magic additive into a half full tank from Halfords about £6.80

After this initial fail I decided to take the car to an independent garage who said he could get the car through, i left the car with him and he passed it. I had no idea how he manged to do it the readings on the council test that failed were 1st test 1.01 - 2nd 1.22 - 3rd 1.10 - 4th 1.13 -5th 1.20 - 6th 1.16 all over the required 0.9. The level required was much higher before and the car would have passed no problem untill the government decided that the tolerance should be lower than that on the door plate 0.9 The independent garage managed to pass me. (probably thrashed my car to get it red hot)

This year 6th Jan 2020 i took the car into the council testing station again as they have no vested interest in selling me any unneeded work which i love !! standard £54.50 I was prepared this time so added some Redex (should have used Diesel Magic) i drove the car into the country side and revved it to 3.5 to 4.5 thousand revs up hills dropped it into 3 gear to make it struggle /work and drove around like an idiot for over an hour trying to get my engine very hot before the Mot time slot at 10am i parked it up and turned the engine off walked away thinking i had done enough this time i arrived back an hour later and it failed again.

All readings were over 0.90 by an average of point 2 very little but enough to fail!! to my dismay he told me to use Diesel Magic and run it very hot on the motorway i drove away bought some diesel magic and drove the car up and down the motorway blasting the throttle and kick-downs for 1 and half hours feeling like an absolute idiot/moron i kept thinking i shouldn't have to do this this is wrong?

The car has been meticulously maintained as per Mercedes protocols from day one fully stamped Mercedes service history!!

After driving over 100 miles going nowhere in particular I arrived back at the testing station
for another test, re-test was free slotted in for 1.30pm same day, he came back to me and said he was gentle ! meaning he didn't really put his foot down as much as maybe he should, but it had indeed passed this time. The average reading was 0.66 1/m.

i was told in future to add diesel magic more often and try premium diesel which i will do until the next test.

I have been told that an updated super duper air filter does the trick i am waiting to find out what exactly or which air filter will be the best one to use? I am aware that the government are trying reduce emissions and trying to reduce the amount of diesels on the road over the next decade. They are the ones that encouraged us to go diesel in the first place!!

How bizarre that i am now out polluting the environment more than i normally would thrashing my car more than i would at any given time throughout the year ? how many thousand of diesel drivers will be doing the same to get their cars through this unfriendly diesel MOT.

Happy New year !!
 

JBell

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I use Archoil AR6400-D MAX on the odd occasion seems to work.

Diesels and short journeys don't make a good combination unless you do a good run every now and then
 

M80

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Millers diesel additive has good opinions.
Add it every 4th fill should be enough.

I will under dose for a couple of fills on an un treatred engine, increasing the dose as I go, and eventually overdose some later.

https://www.ebay.co.uk/itm/Millers-...155592&hash=item2a963c1184:g:5CcAAOSwYwZcUWPf

The wifes Gr cherokee, same engine as yours, belches smoke whenever I take it out as she does a 7 mile commute, only.
Interestingly though I will get better consumption than she will even with my clearing its throat.
 

d215yq

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I'm not sure thrashing it is really necessary to get it red hot. Just drive it 50 miles on a motorway or so before the test. Thrashign it won't get it any hotter...As above, removal of air filter and throwing in veg oil will get it to pass. My test centre were gentle and revved to 1,5k rpm instead of 3k rpm and it passed. Next year I didn't think they would be so put 5L of veg oil on a near empty tank. Came in at 20% of the levels from the year before...
 

js190d

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1991 w201 190d 2.5/ 2002 s210 320cdi avantgarde
Biodiesel will get it below limit , my 06 Jeep grand cherokee 3.0crd was if I remember correctly 0.21 last April.
Im not sure that the original posters 270 cdi engine would accept veg or even bio diesel as a common rail engine.

It's amazing how clean old diesels burn on bio or veg though.
 

Rory

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Your Mercedes
2005 C270CDi Avantgarde Estate. Bought 2005, sold 2022.
On my car door it shows the Plate value as 0.90 1/m drift value 0.08 1/m for my C Class 270CDI 2004 diesel estate

I'm nervous about querying this :) but does yours show the drift value on the plate? Mine doesn't.

Mine has 0.9 in a box with two squares around it, but it's not in the positon various sites say the emissions figure should be.

Previous MOT (18 months ago) the garage I use tested it at 3.0, which is the correct default value for the age of the car. Last MOT they used 1.5, which is for 2008 onwards. It only just passed that, but the engine was nothing like hot.


As for thrashing the car - I do a regular 150 mile very steady motorway trip in mine, and it's very noticeable that if I accelerate hard the next time the car slows then a wodge of smoke comes out the back, but it only does it once. Trouble is, it's hard to put these engines under much load to give them a clear out.
 
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joderest

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Fitting of an oil catch can lowered the emissions at MOT on my ML270, last year was 0.79, went down this year to 0.49. same garage, same testing machine, same tester.
On the MOT States needs to be 0.80 or under to pass, where does the 0.90 come from?
Or am I looking at incorrect thing.
 

Rory

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On the MOT States needs to be 0.80 or under to pass, where does the 0.90 come from?
Or am I looking at incorrect thing.

There's supposed to be a figure in a box on the vehicle identification plate. The MOT guidance says it's usually in the lower right hand corner of the plate, although as I noted above mine (if that's what is) is in a double box and on the left of the plate. Some cars have a separate label with the smoke figure on it.

If there's no figure shown, then the tester uses the default figures.

It seems the plate figures can vary quite a lot between different ages and models of car despite having the same engine.

Edited to add: Mine is like this, with 0.9 in the double box (above Germany).

p011_0_00_02.jpg
 

oigle

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2003 ML270 sold but not forgotten. 2022 Kia EV6 RWD LR
Fitting of an oil catch can lowered the emissions at MOT on my ML270, last year was 0.79, went down this year to 0.49. same garage, same testing machine, same tester.
On the MOT States needs to be 0.80 or under to pass, where does the 0.90 come from?
Or am I looking at incorrect thing.

Have you done an egr delete on yours? That can reduce smoke a lot.
Ian.
 

Bubble

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If the 0.9 figure on the plate were to get defaced and unreadable, it would be tested to the much higher default limit........
 

Gazwould

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The system is flawed as some diesels have low plate values and some high .

A 2009 Ford 1.8 tdci is a high 1.75 which means it's too high for that year and gets tested to a 1.50 default .

The gubberment should go after these Batman cars !

On the other hand you can have 2002 Euro 3 1.9 diesels with a plate value of just 0.60 when a 2014 A Class 1.5 Reno derv is 0.68 !!

The 2002 1.9 , 0.60 , I have a decade of smoke opacity test results and before my ownership and a year after was blowing around 2.00 , back then the default was 3.00 so an easy pass .

Then I started at some point every other tank adding 2 Stroke oil and it tested the year later 1.50 , same tester and serial number of machine .

Continuous use and it got down to 1.00.

Then the 20th of May 2018 came along with it's manufacturers smoke coefficient value vin plate value , the real culprit all along was an old thermostat , still using 2 Stroke because of it's proven record of halving my results , and it now tests at 0.34 .

Now I use in any diesel car , 2 Stroke and 2-EHN both bought in 5L quantities .

The 2-EHN is the active ingredient in all these derv Cetane / performance boosters like Millers Eco Max etc .
2-EHN does get added as part of the package to our pump fuel but not enough to the ordinary fuel , bit more in premium fuel but you'll be paying for it !!

https://en.m.wikipedia.org/wiki/Cetane_Improver
 

malcolm E53 AMG

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I think any diesel pre EU5 (mandatory DPF) is now good game for the government MoT test. It’s going to be difficult to keep these cars on the road in the long term
 

V6Matty

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The system is flawed as some diesels have low plate values and some high .

A 2009 Ford 1.8 tdci is a high 1.75 which means it's too high for that year and gets tested to a 1.50 default .

The gubberment should go after these Batman cars !

On the other hand you can have 2002 Euro 3 1.9 diesels with a plate value of just 0.60 when a 2014 A Class 1.5 Reno derv is 0.68 !!

The 2002 1.9 , 0.60 , I have a decade of smoke opacity test results and before my ownership and a year after was blowing around 2.00 , back then the default was 3.00 so an easy pass .

Then I started at some point every other tank adding 2 Stroke oil and it tested the year later 1.50 , same tester and serial number of machine .

Continuous use and it got down to 1.00.

Then the 20th of May 2018 came along with it's manufacturers smoke coefficient value vin plate value , the real culprit all along was an old thermostat , still using 2 Stroke because of it's proven record of halving my results , and it now tests at 0.34 .

Now I use in any diesel car , 2 Stroke and 2-EHN both bought in 5L quantities .

The 2-EHN is the active ingredient in all these derv Cetane / performance boosters like Millers Eco Max etc .
2-EHN does get added as part of the package to our pump fuel but not enough to the ordinary fuel , bit more in premium fuel but you'll be paying for it !!

https://en.m.wikipedia.org/wiki/Cetane_Improver
The wife’s 05 A180 just had its MOT, smoke test was .29 the car never had premium fuel, no boosters or 2 stroke, so I personally find those a bit of snake oil claims, not saying they don’t work in some cars but it’s don’t believe it should be touted as a fix all
 

00slk

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All the more reason to buy petrol cars ;)
 

Gazwould

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That's what the gubberment wants you to do to earn more VAT from the purchase , the VED and fuel duty of petrol through less mpg .


These additives reduce the diesel ignition delay by simply having fuel molecules that ignite under compression earlier and act as a catalyst , 2 Stroke oil , 2-EHN , acetone , paraffin , kerosene , petroleum , naphtha , it's not rocket science .

Petrol has the opposite issue of wanting to ignite too early .

What a cars plate value is and what it tests at can be wildly different .

Why I'm saying it works is because I have a decades worth of smoke opacity tests and the reductions corrospond with the use and then further reduction with the new thermostat .

I can make the 2002 test at 0.05 and indeed did last MOT with the removal of a fuse !!
 

Rory

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2005 C270CDi Avantgarde Estate. Bought 2005, sold 2022.
If the 0.9 figure on the plate were to get defaced and unreadable, it would be tested to the much higher default limit........

Yes. Bearing mind MOT testers aren't supposed to dismantle anything I wondered if I could just stick black tape over it!

There was talk of them being able to look up the value using car's VIN but that hasn't happened yet.
 

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