MOT time - old diesel engine and fuel

Channel Hopper

Channel Hopper

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The car in the yard needs an MOT (again), but I haven't used her for a number of weeks/months and even though I've drained most of the fuel out of the tank, I know what is left has been languishing in there since 2013.

The detail on the MOT conditions state 'drive straight to the station' but being a diesel she is going to need warming up for a few miles to clear out the exhaust/particulates in order to do OK in the emissions test.

How literally is the 'drive straight' part in the suggestions and could I get away with a ten mile run ?
 
Tricky. How observant are the local bobbies, especially the ones in cars with ANPR? What about static ANPR cameras? Can you head out and then come back so you're only off route for a couple of miles. In fact, how far away is the MOT station?
 
Any country roads nearby which could be driven round at night?


Just to make sure everything is ok.
 
Over this way in Bucks a few of our villages now have little fixed ANPR cameras.
 
Is it SORN at the moment and how far is the MOT station?

Fast idle it before setting off, to bring the engine up to temperature and then drive in as low a gear as possible to keep the revs up.
 
Captain Jack said:
Is it SORN at the moment and how far is the MOT station?

Fast idle it before setting off, to bring the engine up to temperature and then drive in as low a gear as possible to keep the revs up.
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MOT station is the other end of the high street (about 800 metres away).

Car is taxed (and insured) so no need to SORN, just the MOT is out of date.

Just thinking out aloud, but should she fail on nothing except the emissions (air filter, fuel filter, and clean oil in the sump all done recently), how does one fix it without going for a long run ?
 
The garage should know, if not explain it to them, they will leave it running, or take it out for a run, to ensure the engine is running at peak performance.
 
I wouldn't normally say such a thing (Being the original goody three shoes), but quite frankly I think that, provided you can prove to plod that the MoT is booked, you should go for as long a drive as you think you need, earlier that same day.

Even if stopped, your dilemma falls well within the scope for discretion any worthwhile Copper can exercise.

A risk worth taking.
 
Mickha said:
The garage should know, if not explain it to them, they will leave it running, or take it out for a run, to ensure the engine is running at peak performance.
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Not this garage, despite being good to me with the motorbikes, they have no spare staff at the moment to take a car out for a spin before the test. They have been run off their feet in the past month
 
Even if stopped, your dilemma falls well within the scope for discretion any worthwhile Copper can exercise.

Besides, the car had been stored at your mother/father/sister's/mate's house, so you were driving it directly to the MOT from Birmingham :)
 
At our garage , if you explain your predicament, and it didnt go through the smoke test, the mot tester will drive it round the block to get it hot, or even retry the smoke test at the end of the MOT.
 
If it still fails miserably get some diesel additive and put that neat in the tank without too much fuel, this should clear the injector sprays too and any gum in the fuel lines etc.
 
Thanks, though I am somewhat concerned I have to rely on 'discretion' of local plod rather than legislation within UK law.
 
Stick some forte cleaner directly into the fuel filter cap if you can... Best way. Or as PDP says if that fails.
 
Captain Jack said:
Stick some forte cleaner directly into the fuel filter cap if you can... Best way. Or as PDP says if that fails.
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I was thinking of forte diesel injector cleaner aswell!! We use lots of forte gear, expensive but its the best.
 
Never heard of it, but the bottle looks suspiciously like the Red-Ex of olde.
 
Why should having the car standing for a while make the injectors not work properly? The way I see it "taking the car for a run" to "get it warmed up properly" is just an act of desperation for something that is already broken; A bit like putting a hi-gain LNB on a dish that is too small. And diesel is oil so it's not like old petrol that loses its spirit content if it is in the tank for too long.
 
In order to give the best particulate emission result, it's important to warm a diesel engine up properly. Advantage can also be taken on this run to do an "Italian" tune-up (rev hard in low gears) to clear any of the particulates that have settled in the exhaust system.

There's also the possibility that the vehicle might have winter diesel in it, Winter diesel has anti-waxing agents added whilst summer diesel has anti-foaming agaents added. Winter dieseel already in the car probably won't give any trouble but the other way round could concievably be problematic in extremis.

No desperation in warming the car up if a busy garage doesn't have the time to do it properly. Leaving it idling is definitely not the best way.
 
Huevos said:
Why should having the car standing for a while make the injectors not work properly? The way I see it "taking the car for a run" to "get it warmed up properly" is just an act of desperation for something that is already broke.
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In the UK there are stringent tests for emissions on diesel vehicles, there is little point in having the car fail a test just because it's been left standing for a while.


Huevos said:
And diesel is oil so it's not like old petrol that loses its spirit content if it is in the tank for too long.
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Diesel does go off. Google pseudomonas and cladisporium resinae, which can appear after a while if the conditions are right
 
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