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post #1 of 7 (permalink) Old 05-19-03, 09:33 PM Thread Starter
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5W30 or 10W20??

On the oil cap in my AU XR6, it says to use 5W oil. However, when I take it in for service, I've noticed (on the invoice) that they put 10W oil in?? Would there be any difference in engine performance or should I insist on them using 5W oil???
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post #2 of 7 (permalink) Old 05-19-03, 10:50 PM
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As the saying goes Oils Aint Oils!

The oil numbers mean viscosity cold / viscosity hot

Meaning a 5w oil will move faster and protect agaisnt wear faster than a 10w oil, and then as it gets hotter it gets thicker so as you mentioned a 5/30 oil will be thinner at cold, and thicker at hot (stick to the engine bits more) and the 10/20 will be thicker at start, and thinner at hot so not sticking to bits so much.

I would go with the 5/30 if I were you, not a 10/20 (not that I have heard of a 10/20 oil)


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post #3 of 7 (permalink) Old 05-19-03, 11:38 PM
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You can get 0W20 I think the 4.6 Mustangs run it and probably the Falcon 5.4s also.

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post #4 of 7 (permalink) Old 05-20-03, 12:44 AM
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I would have thought a 5W-30 or a 10W-20 would not be good for Australian Conditions.

That kind of oil would be great for somewhere cold and where there is snow but think about how it would protect come summer months.

The Mobil 1 I use is 5W-50 and I think offers the best all round protection.

The first thing I would be doing is consulting the service manual

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post #5 of 7 (permalink) Old 05-20-03, 12:54 AM
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i was under the impression that they first came out with a 5W/30 rating and then ford upgraded the requirement to 10W

that was my understanding anyway

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post #6 of 7 (permalink) Old 05-20-03, 02:50 AM
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Yeah, that's right. I reckon a 5W oil is too thin for Australian conditions, unless you live at Mawson :)

I wouldn't even use a 10W oil, but then again that depends on the mileage of the motor.

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post #7 of 7 (permalink) Old 05-20-03, 03:32 AM
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These engines now run tighter clearances and are designed to run thinner oil to maintain oil volume especially at cold temps where most the wear is..But really it doesn't matter too much so long as there is quality oil in there and changed often...imo

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