Hey all, im new to this forum. I've been thru all related posts for my question but couldn't find a conclusive answer. So here are my queries: Engine: ford 1.5 tdci run 40k kms. Weather: min 60F Max 115F Usage: stop and go heavy traffic and highway (50:50) Currently running ford spec 5w30 a5/b5 913c oil (mobil 3000). The official OCI is 10k kms but I've found the engine gets noisy and rough after around 7k kms. Hence i stick to the 7k kms OCI Engine consumes ~300-400 ml of oil in that period. From what I've read, A5/b5 is a resource conserving oil with lower hths. And the 913c spec mandates extra zddp in the oil. Would i be better off using a 5w30 A3/B4 oil or even an E7/E9 oil? Would the higher HTHS and lower zddp in these oils cause more wear or less? Im not bothered about about the fuel economy drop (which i assume would be marginal) What would be the best oil for my usage and climate?