I know there's been lots of discussion on oils but I'm not finding much about this, specifically.

I've looked at viscosity charts and it seems 5-30 or 10-30 is not heavy enough for temps approaching, at or above 100 degrees.

Any body using 10-40?

My engine is a '96 1797 jdm, b18c.
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Anybody?

 

what's the manufacturer recommended spec? (pretty sure it's 5W-30)

what is your reasoning for needing something different? (results/recommendation from Blackstone lab oil analysis would be a good one)

the link below is a good read.
https://ricksfreeautorepairadvice.co...pecifications/

I have found a lot of internet search results on the topic, even from oil manufacturers and other relatively legitimate sources still have misinformation, oversimplification or just lazy copy-from-Wikipedia type explanations. not helpful...

 

Why is it, all the viscosity charts show 30, 5-30 and 10-30 not reaching 100 degrees? I've looked up several of them. They don't.

How can any manufacturer specify a grade for everywhere?

 

Did you read the linked article? read it. it points out that most of those charts are showing the temp range used for the testing procedure. that's why they are misleading/confusing important info is left out to "dumb it down" i guess. also, safe to assume 100°C so 212°F (near normal operating temp) since that is the standard temp for cSt measurements.

all three, SAE 30, 5W-30 and 10W-30 should have the same viscosity (within the specified range...) at operating temp. Drive from Alaska to Arizona; your engine temp (therefore your oil temp) should be the same ...if your radiator is functioning properly

ambient temperatures effects on engine oil really only come into play at startup and for the first 10-15 minutes of operation until you reach normal operating temp.

 

Yeah, I get your point. You don't think, even with my brand new oil and water pumps....and 1 year old radiator, that diving on a 100 degree day will raise the engine temp any higher than spec.

New 12 inch fans too, but 100 degree day means 110-115 on the highway surface. I spun a center main bearing that way once... different car tho.

 

I'm going to try some 20W-50 in my car at the next oil change and see how it does in the hot months. I've been happy with 10W-30 in the cool months.

 

Hondamark and the article referred to made one specific thought come to mind. The Honda/Acuras are built with tight tolerances. That would make it possible that higher grade, thicker oil...might not circulate thru those tight tolerances as well.

That's what made me decide NOT to use higher grade oil.