I agree 100% with 4ePajero. That oil you are using is the wrong multi grade for your engine. If it take that long to stop the tappets making noises, how many other moving parts are deprived of that golden product that is supposed to lubricate them cause serious wear.
I still suggest Delo400 multigrade (15W - 40). 10 liter of expensive oil is much cheaper than re-building an engine. I still want to see the oil that will remove sludge, and prevent it from building up, in a quicker and better way than Delo400.
Don't you think it is worth trying? Never heard of a person using Delo400 complaining about the results. What is the chance that they all use the wrong oil?
A POST BY A CONCERNED CLUB MEMBER AND PART OF THE FAMILY OFF PROUD PAJERO OWNERS.
Let us know of the results.
Waldo Fourie
PS. This past weekend a colleaque of mine bought 5liter Delo400 from Midas for R185 incl. VAT