[MSS]

Originally Posted by bl52krz

My car failed the mot on emissions this year,March. Just to concentrate on diesel, I was advised to change my engine oil to a C3 derivative to help with emissions.I was also advised to use the ‘better quality’ diesel fuel for the re-test. I filled up with C3 oil as suggested, and also put around 10 gallons of BP ‘best quality’ diesel in the tank.
I cleaned the egr out. Not much gunk in it. My car passed the mot test. I continued using BPs finest for the next two fill ups. My conclusions were:- Same mpg. The engine did seem to pick up revs easier. The last two fill ups were from Asda, the terrible junk diesel.The mpg was the same. It picked up revs just as easy as when on BPs super duper diesel. My only conclusion from this is:- that the Magnatec C3 fully synthetic 5w40 oil was what made the difference in the faster pick up. It is also recommended for the diesel in place of 10w40. It achieved the same test results as the 10w40..

Could it also be that the premium fuel cleaned the injectors etc. and this is benefiting the follow-on refills with non-premium fuel?