About to change oil on 59 plate 1.6 hdi 90. 76,000 on clock and running reasonably well. Tend to get a noise similar to when you labour an engine when under 1500 revs in 4th and 5th with load on engine. Disappears on overrun or when doing 1800 revs and over. DavidIreland always recommends Total quartz ineo 5w30 C2 and I tend to stick to what he suggests. However a new oil has been manufactured by Total. TOTAL QUARTZ INEO FIRST 0W30. Citroen Peugeot use it on new cars as they come off the line and also recommend it for refill. Being thinner oil would it help reduce labouring noise, would a remap up to 120 help, is there a common cause for this or is it me being tight on the fuel by driving under 1500 revs in high gears? More noticeable when more than one in car. Open to suggestions.