Any truth to 5w-20 and cooling?

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453
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northeast
My brother just purchased a 09 Acura TSX 2.4 liter 201 HP. When he asked about the oil being 5w-20, he said he was told that they use that becuse not only of the small allowances, but they have found that it helps to assist in keeping the engine running cooler??? anyone hear of this before? or was his leg being pulled? thanks
 
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25,046
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ON, Canada eh?
It's 5w20 month at BITOG... Bob tell him what he has won! You will hear from some that say a 20wt is better, and some will say a 50wt is better... It's a mixed bag. I have tried both and have not noticed a difference.
 

JHZR2

Staff member
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New Jersey
"small allowances" You mean tolerances? That has been discussed in detail here, the tolerances are likely no different than a civic from 10 years ago that was specced to run 10w-30. I'd also venture to guess that in other parts of the world, other grades are specified to be used in that engine at various temperature ranges. It is because we have designed and enabled such good 20wt oils, that we can use them with confidence. The cooling aspect may have some truth to it, but is for the most part irrelevant to why they use this oil. The real reason is because people have been tricked into thinking that they NEED 200 hp. As a result, they have vehicles that are thirstier - direct contrast to CAFE and being "green", mandating higher fuel economy, etc. One way to benefit fuel economy and eek out each last bit possible is to run a lighter oil, which can yield a few percentage points of economy. SInce as mentioned before, we have designed and specced 20wt oils to be so good, they typically can take the application without issue.
 
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Ontario, Canada
 Originally Posted By: FZ1
Thinner oil runs cooler. Synthetic oil runs cooler. They shot him straight.
Which is why Honda spec's a 5w30 for the performance version right?
 
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CA
 Originally Posted By: OVERK1LL
 Originally Posted By: FZ1
Thinner oil runs cooler. Synthetic oil runs cooler. They shot him straight.
Which is why Honda spec's a 5w30 for the performance version right?
 
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Billings, MT
 Originally Posted By: tonycarguy
If lighter weights are better for cooling, why do motorcycles (aircooled) run 40 or 50 wt, and racing apps run 50 or 60 wt?
Because they get stupid hot, which really thins the oil out.
 
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KC
 Originally Posted By: OVERK1LL
 Originally Posted By: FZ1
Thinner oil runs cooler. Synthetic oil runs cooler. They shot him straight.
Which is why Honda spec's a 5w30 for the performance version right?
chronic fuel dilution?
 
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