Passing the Emissions part of the MOT test (1 Viewer)

Jim

Ringleader
Jul 19, 2007
36,195
128,633
Sutton on Sea, UK
Funster No
1
MH
Adria Panel Van.
Exp
Since 1988
Someone has asked me about what to do with an older van that has failed the emissions part of the MOT.

What might have caused it and what should they do before re-test to try and pass before they buy a new engine! Over to you..:)
 

Steve

LIFE MEMBER
May 8, 2013
1,613
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Compton Berkshire
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C class
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on and off for 40 years
First it really needs to be serviced, oil flush and changed, air filter, fuel filter if you can a good dose of injector cleaner with not much fuel in the tank. A good Hard run ( always a debatable issue) if then runs nice with not smoke take it for test. If thinks are still bad then there are a few more things to try before the spanners come out.
 

Kevan

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Jan 18, 2014
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van conversion
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30 years caravan/motorhome
Agree, a good run, using the gears, blow the cobwebs out. try a diesel additive to clean the bores etc, most garage's sell it or a motor factors.

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GWAYGWAY

Free Member
Sep 6, 2014
4,213
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Dover
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Hymer ML I 580
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4 years
Exhaust recirculation system gets blocked with black sooty oily GUNGE it is waful goo and really mucks up the whole engine , Blocked or dirty Filter, for the air intake and the turbo are all likely to cause it to fail as the engine is getting oily air to breath which is not helping to having a clean exhaust emission. An ITALIAN TUNE UP is one of the best ways of clearing the system. A merciless thrash in lower gear up hills with a load make the temperature rise in the exhaust and burn off a load of the mess. It needs a really good thrash though to do it. Most motorhomes are babied far too much so they do block up. A good lashing of injector cleaner ( good one) will help the situation at the same time.
 
Aug 18, 2014
23,539
131,311
Lorca,Murcia,Spain
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32,898
MH
Transit PVC
Exp
16 years since restarting
@Jim hasn't said whether petrol or diesel though ?
If it is a diesel then basicallywhat all the others have said.
Mine passed here this a.m with a 0,86(y)
 

Bailey58

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Jun 23, 2010
8,785
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Norfolk and Toftir.
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Sold
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July 2010 (ex tugger)
My local garage gives my old Espace a good wellie down the bypass before it's MOT, passed with flying colours, passed again this year.

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Peter JohnsCross MH

Funster
Deceased RIP
Jan 5, 2008
9,617
6,194
East Sussex
Funster No
1,134
MH
Autotrail
Exp
1995
Dunno this was years ago on very old landrovers, but I doubt if a weak solution being used for ten minutes would harm as the 90% diesel content would still lubricate.

Running a diesel on a high petrol content in the event of a missfill would

Peter

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andy63

Free Member
Jan 19, 2014
4,672
15,017
south shields
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None
Exp
since 1990
what to do with an older van that has failed the emissions part of the MOT.

Older vehicles were just subject to a smoke test... I assume it's just the same now as they didnt produce emission criteria for old vehicles to meet...
As has been said... a service changing oil and filters including air... and make sure the engine is warmed up just prior...
If it still fails then the garages usually recommend a fuel treatment like the forte before bringing it back..
If that doesn't sort it its a trip to the fuel injection shop to have the injector's serviced and pump set.
Andy
 

laird of Dunstan

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Feb 15, 2015
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lincolnshire
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Rapido 9000DFH
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ex caravanner
Try using some rapeseed oil ,I used to run my old pajero on a rapeseed /diesel mix ,never had issues with emissions test ,did get the odd drunk thinking I was a chip shop on wheels
 

PeteH

Free Member
Nov 22, 2007
6,853
9,029
East Riding of Yorkshire
Funster No
900
MH
Rapido, 999M.
Exp
18+yrs plus 25+Towing
I suspect that anything which reduces un-burnt hydrocarbons, will be of Help. Good maintenance is key, Taking it in good and hot, and all those things suggested will help. but nothing will help an old "Dog" short of an engine re-build.:(
 
Oct 7, 2015
736
3,576
newark
Funster No
39,285
MH
Swift escape 624
Exp
1999
We always used to
Remove the air filter then drain the fuel filter and fill it with injection cleaner then run it for a few miles, an oil change helps
 

GWAYGWAY

Free Member
Sep 6, 2014
4,213
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Dover
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33,216
MH
Hymer ML I 580
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4 years
I understood that putting any amount of petrol in a modern diesel would cause severe damage to oil seals etc???
It is not the seals that suffer it is the very close tolerances in the high pressure pump that use the diesel for lubrication, petrol and paraffin break down the lubricity and can seize the HP pump, solid. They are just a bit pricey.
It was one of the problems trying to make light aircraft diesel engines that use Jet A1 ( rough kerosene) as fuel the pumps needed to be lubricated and it was a difficult job.

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TheBig1

LIFE MEMBER
Nov 27, 2011
17,509
42,755
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
to summarise. an oil and filter service and a can of forte followed by an italian tuneup the present for mot with the engine nice and warmed up.

all i would add is after the forte, next fill up and at least every forth use one of the premium diesels v-power ultimate etc. it has added detergents to keep the engine clean
 

Flamenca

LIFE MEMBER
Jun 21, 2013
1,266
804
Europe
Funster No
26,598
MH
Hymer 564
Exp
Since 2010
Last year I added 500ml Wynn's Professional Formula Diesel Clean 3 Extreme Cleaner and gave it an 'Italian tuneup' and it passed the MOT smoke test (my 23 year old does not require full emissions test). This year I intend to add 1 litre of Dipetane in an attempt to make the exhaust even cleaner.
 

stcyr

Free Member
Apr 11, 2011
1,765
1,160
Normandie
Funster No
16,005
MH
A class
Exp
On & off, since 1966 - fulltime since 2005
<----- 1991 - no problems with emissions...

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