Originally Posted By: aquariuscsm
If Nissan VQs are anything like VGs,they`ll love the thicker oils. I read on my350z.com that the VGs do in fact respond better to thicker oils vs thinner ones. 40 weights seem to be a popular choice (0W40,5W40,10W40,and 15W40).
To an extent, going back to Dino killed the slight ticking noise I would experience, the MC5k is a CST 10.6, the synthetics I used were lower. The X forums recommended Mobil 1 as this has corrected a lot of noises they experienced. Mobil 1's cst is 11.3.
I've tried PP, QS HP and Valv Synpower with the same results(noise). QS was fine until about 1-1.5k in to the OCI and the noise would come back. I'm now over 2.5k on MC5k and no noise.
Wife's Grand AM GT did not like QS HP. Car sounded different, and at first I thought it was a faulty filter so I swapped the Delco to a PPO and same noises. This OCI I put in 0w30 Mobil 1 AFE and you can barely hear the car running.
Thicker oils can help, but if you switch to a heavier weight of oil you just need to be cautious. Throwing in a 40w in a Versa engine may or may not have issues dependent on engine design. Secondly the heavier you go, the less fuel economy you get(albeit very minor, but in some cars its a noticeable difference).
I also believe the formulation of the oil(additives etc) determine the role they play in an engine. Certain oils work better in certain engines. Some play nice with all oils and others do not.