I suggest you start a new thread of your own.Hi, hope you an help. Have an oil change issue. I have recently changed the oil to Mobil1 05/40. Now the engine runs rough as a dog and has a slight vibration. hope you can shed some light on the matter.
Thanks 2004 93 t arc Petrol....
I agree on the flow issue... 80-90% of wear happens at start up. So, I was using 0w-40. However, I had increased consumption with it. If you check the actual viscosity measurements, it's on the low side for a 40 weight. I switched to Rotella 5W-40 and I was much happier. Rotella has a higher viscosity even though it's also rated as a 40 weight. Also, the guys with pressure gauges report better pressure with it. Cold starts seem unaffected, but science tells me I get slightly slower flow with a 5W vs. a 0W. M1 meets the shear specs, but I have seen some argument that it still breaks down more than desired after some wear. Some guys reported low pressure after a hot run.Thanks for the info. I figured the differences in oil weren't too extreme, but if there are significant benefits to a certain oil type/regimen, I'll do it.
Rotella T6 5W-40 is quite a bit cheaper, and my local stores don't seem to stock M1 5W-40. 0W-40 is readily available, so I might give that a try.
Based on this thread I was under the impression that Mobil 1 products didnt provide enough oil pressure at the same weights, and there was some talk of shearing issues. Honestly I don't know squat about the science that goes into these products or the accuracy of tests. I don't have a tuned engine so I think I should be fine as long as I'm in the ballpark. The one quality I'm most concerned about is whatever flows well during cold starts and lubricates parts effectively in the shortest amount of time, while still maintaining proper protection once the engine is warm.