Thinner oils wear more the engine at startup Proof

OVERKILL

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Originally Posted By: Pontual
Hear how quickier the engine turns with 5w30, as opposed to 15w40, specially for the initial 10 seconds. It gives a lot of spin while the pressure builds up. Even the tick-rattle of valve train is way more pronounced with the thinner oil. Sound test comparison:) https://www.youtube.com/watch?v=mKHwq1b3004 Start
You do realize an oil pump is positive displacement and when not on the relief, is moving essentially the same amount of oil per rotation whether it is 5w-30 or 15w-40 right?
 
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An engine spins the same at start up regardless of oil weight. A thicker oil would only put a larger load on the engine, but would only be noticeable at colder temps.
 

CT8

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Originally Posted By: OVERKILL
Originally Posted By: Pontual
Hear how quickier the engine turns with 5w30, as opposed to 15w40, specially for the initial 10 seconds. It gives a lot of spin while the pressure builds up. Even the tick-rattle of valve train is way more pronounced with the thinner oil. Sound test comparison:) https://www.youtube.com/watch?v=mKHwq1b3004 Start
You do realize an oil pump is positive displacement and when not on the relief, is moving essentially the same amount of oil per rotation whether it is 5w-30 or 15w-40 right?
Until the oils gets to the temperature where the heavier oil fails to move from the pan to the pump.
 
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Originally Posted By: OVERKILL
You do realize an oil pump is positive displacement and when not on the relief, is moving essentially the same amount of oil per rotation whether it is 5w-30 or 15w-40 right?
^^This
 
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Holden recommends the 5w-30 grade for the old Build 3800 V6 in everyday driving in Austrlia but in the snow or extreme cold it recommends the 15w-40 grade. Is the Holden / GM recommendation flawed ? There is some truth to the OPs claim thinner oils do were more in certain conditions and climate. A sound test to evaluate wear could be the ??
 
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Originally Posted By: gregk24
Sorry, your logic is flawed.
Nah, the logic is fine. The premise is the problem. smile
 
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Originally Posted By: virginoil
Holden recommends the 5w-30 grade for the old Build 3800 V6 in everyday driving in Austrlia but in the snow or extreme cold it recommends the 15w-40 grade. Is the Holden / GM recommendation flawed ? There is some truth the OPs claim thinner oils do were more in certain conditions and climate.
I personally think they are flawed. I have never seen a weight recommendation go up if the temperature gets colder. The 3800 here isn't spec'd for that plus I'm sure they'd see much colder temps further north.
 

OVERKILL

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Originally Posted By: CT8
Originally Posted By: OVERKILL
Originally Posted By: Pontual
Hear how quickier the engine turns with 5w30, as opposed to 15w40, specially for the initial 10 seconds. It gives a lot of spin while the pressure builds up. Even the tick-rattle of valve train is way more pronounced with the thinner oil. Sound test comparison:) https://www.youtube.com/watch?v=mKHwq1b3004 Start
You do realize an oil pump is positive displacement and when not on the relief, is moving essentially the same amount of oil per rotation whether it is 5w-30 or 15w-40 right?
Until the oils gets to the temperature where the heavier oil fails to move from the pan to the pump.
That's kind of funny coming from a guy in California, LOL! When's the last time you saw -30C? wink Yes, while running straight 40 (or even a 15w-40) in Winterpeg when it is -40C might result in the oil failing to pump, this is generally not a concern for most people. The "fail to pump" point for a 15w-40 is still quite cold given that the MRV for a 15W is performed at -25C:
 
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Originally Posted By: virginoil
Holden recommends the 5w-30 grade for the old Build 3800 V6 in everyday driving in Austrlia but in the snow or extreme cold it recommends the 15w-40 grade. Is the Holden / GM recommendation flawed ? There is some truth to the OPs claim thinner oils do were more in certain conditions and climate. A sound test to evaluate wear could be the ??
That sounds backwards to me. 15w40 dino was the most common oil in Germany for decades and the engines would be a real bugger to start in real cold weather. Many wouldn't even turn over. Synthetics and the move to 10wXX took care of that problem for the most part.
 
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So a guy comes in with some evidence he collected showing a thinner oil (5w30) makes less noise at startup than a thicker oil (15w40) and that he thinks it causes less oil, and everyone is telling him he is wrong? This is just the sort of thing that some folks have been demanding for some time. duh well done, BITOG. [insert discussion here about ambient temperature]
 
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Originally Posted By: Kuato
So a guy comes in with some evidence he collected showing a thinner oil (5w30) makes less noise at startup than a thicker oil (15w40) and that he thinks it causes less oil, and everyone is telling him he is wrong? This is just the sort of thing that some folks have been demanding for some time. duh well done, BITOG. [insert discussion here about ambient temperature]
Reread what you said. It makes zero sense. Also look at the title.. While it appears English isn't the OPs first language, I'd hope one can decipher it enough to know he's talking about wear. Engine speed is also mentioned in his first post.
 
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