MOT Basic Emission Test

Baldytyke88

Does this test result tell me anything about my engine? It's passed with an opacity of 0.70 the RPM was 715 and 3686

It states that the fast pass limit is 0.90 and the default is 1.50

My 2l Vivaro has done 82k miles, is 0.70 a good result, and I assume a lower result means a cleaner and less worn engine?

Goudy

It means it's burning it's fuel efficiently enough for the government but how efficiently depends on the manufacturers specification.

It only needed the Fast Test to pass. If it had failed that they would have performed 6 more tests and taken an average of the best three, which may or may not pass. So you can see, there's a fair bit of leeway between what is correct for your vehicle and the test level set by some suits in a government office somewhere.

You could get an old cluncker to pass if you can balance the air and whatever it's using for fuel properly.

If it was mine I would take it as it appears to be fuelling well. The pistons are compressing and burning a precise amount of air and fuel. With it being only at 82k, the engine (piston, bores, bearing and crank) should be in fine fettle for a diesel engine.

On the other hand a brand new engine could fail miserably if it had a split in a £3 intercooler hose as that just throws the fuel air balance right off. So take that data from the test with a pinch of salt.

Baldytyke88

https://forums.moneysavingexpert.com/discussion/comment/82024268#Comment_82024268

When I reverse into my drive, because it's enclosed, the exhaust smell is always there. But my engine oil is still clean after a few thousand miles, so I'm hoping all is ok.

Mildly_Miffed

Smoke opacity is soot. On any diesel more recent than the late '00s, Euro5 or 6, it really ought to be near as dammit zero, certainly <1.0 - that's the whole job of the DPF.

Look on the VIN plate, and there'll be a figure in a box. That's the manufacturer's limit for YOUR VAN. Sounds like it's 0.9. 1.5 is the default if the vehicle-specific figure can't be found.

From memory, with old-school diesels pre-DPF, it used to be about 2.5 to 3.0 as the default.

James2k

https://forums.moneysavingexpert.com/discussion/comment/82024297#Comment_82024297

If it's a diesel, your oil won't be clean within seconds of starting after an oil change