Quote:
Originally Posted by vorsprung durch technik
I put Mobile One 0w 40 in the Cortina Mk5 in 87 and hated the stuff.It made the 2.0 pinto engine sound course/rough.Cost a fortune i remember.Was only in there a day or so,i hated it, before i dropped it out and probably refilled with Castrol GTX 20w 50 to restore it's normal smoothness.
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Mobil One was 5W/50 in 1987. If memory serves, it changed to 0W/40 in the late nineties. So the same viscosity as your 20W/50 at operating temperature (or at 100 deg. Celsius to be correct)
Quote:
Originally Posted by Isimmo
I must admit, when I read 0w40 I winced slightly. It's a bit thin, certainly for the B2's/Ur and B4 20vT 5 pots... But if it works for you, fair play...  |
What did you wince at? I'll guess it was the '0W'. WHY? The 'W' stands for winter. The '0' relates to the viscosity at 0deg. Celsius. The lower the first number, the thinner the oil when its cold. That means it gets to the top of the engine quicker on cold starts, which is a (very) good thing and flows more freely at low temps. The higher the second number, the thicker (or less thin would be more accurate) it is at 100deg. Celsius, but no oil gets thicker when it gets hot - and to work properly it needs to be hot. So
0W/40, 5W/40, 10W/40 oils are all exactly the same viscosity at operating temperature
and are ALL thinner than the '0' viscosity!
Quote:
Originally Posted by vorsprung durch technik
5w 40 is good but no lower on the lower end. As for Semi synthetic or Fully synthetic it depends how much you love your car. Fully synthetic stays in grade for a long long time under all conditions hence why it's more expensive than a semi synth which is a mix of mineral oil therefore breaking down far quicker than a full Synth. |
Why would you not go lower than 5W? A lot of people seem to be frightened by the '0' but your oil only gets thinner as it gets hot.....
Quote:
Originally Posted by Isimmo
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I contacted Opie Oils some time ago about using Mobil One 0W/40 to get their view. Answer: Mobil One 0W/40 is suitable for your engines. (Bear in mind of course that Opie are not promoting Mobil One any more than any of the other oils they sell.
Please, don't get me wrong. I'm not advocating that anybody should use any particular oil. Far from it - use what you are happy with. Just trying to point out that any XW/40 oil is the same as any other XW/40 oil as far as viscosity is concerned at operating temperature and the thinner it is when its cold, the better. What's more important is the additives that the more expensive oils have. Price, brand loyalty, advertising spiel and 'pub talk' are probably the main reasons for the oil of choice for most.