Thread: 30w oil
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Old 02-14-2019, 01:49 PM   #20
ryanheacox
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Default Re: 30w oil

Quote:
Originally Posted by Allanw View Post
Wear happens with cold, thick oil.


At no point in normal operation will a 0W-40 get thinner than the SAE40 - they are both the same viscosity when hot, which is when they are the thinnest.
This makes sense to me but I remember reading in the owners manual for my Jeep that 5w-30 is only recommended for sustained temps below freezing AND that using 5w-30 in higher temps would lead to an increase in oil consumption compared to the 10w-30 recommended for above freezing use.

If they both flow like SAE 30 when hot (which they should), why would oil consumption change?
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