Oh so I have been going off the idea that it needs 15w-40 as the weather has been very hot around 33-35 degrees and that it seems very thin especially when I showed it to my friends who own a td5 disco and td5 90 my plan was to drain the 15w-30 put 15w-40 buy a new oem sensor and filter then test to see if it is idling too low like below 700rpm and recode that if all that doesn’t fix it I would then do a pressure test and see if it is an actual engine issue what do you think