Having not used the Forum after the last lot of advice which solved my MB problems, I am back!! I have a Hymer motorhome which has a custom body (A Class) manufactured in 1996 and powered by the excellent 2.9 5 cylinder OM602 diesel engine. For the last 4 years I have wandered Europe and spend the winter months down near Malaga trying to avoid the UK winter. Apart from a failed alternator pulley bearing The Beast has performed without any issues. However, I read the glad tidings that VOSA/DVLA are tightening up the MOT regs and it concerns me that this might well impact me. When I first bought the MH 5 years ago it was running on mineral oil, but successive services at my local MB main dealer have changed the oil type to Fully Synthetic. A previous post I read mentioned that the thinner synthetic oil would likely find the opportunity to seep out if possible and I have noticed that The Beast pushes out a little blue smoke when idling. I run The Beast at 4.6 tonnes and normally pull a Smart car on a trailer, and performance is very good, BUT if I am going up a steep incline in very low gear (its automatic of the tree trunk variety sticking up through the floor!!) I get black smoke if it is hot. Question: I have never seen MB put any form of diagnostic unit/laptop any where near the vehicle, so is there a way of checking that my fuel flow etc are optimum, or is my 602 a bit early for all the fancy electronic monitoring?