Low oil pressure/ Rotella 15w40

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Got my Yukon tuned yday and the guy mentioned my oil pressure was slightly low. He said I could get the pressure up by running Rotella 15w40. Has anyone done this or heard of this?
 
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HurricaneSSeason
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That's diesel oil. What is your pressure at idle once fully warmed up?
I know it's diesel oil, but I have heard of C10 guys using it in motors w flat tappet cams (if that's what they're called). My gauge usually reads 35-40 psi, but he was looking at it thru his tuning program so it was probably more accurate.
 

swathdiver

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It probably is but what does slightly low mean? Minimum oil pressure is 6 psi and mid twenties is normal. If yours is in the teens or lower I would be replacing the o-ring and maybe the pump, not the viscosity of the oil used.
 

CountryBoy19

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FWIW, I've been running 15W40 in my Buick 3800 since I bought it (72k miles) and it now has 256k miles on it. If it has killed the CATs it didn't trip any codes about CAT performance...

I've never had any troubles related to engine oil, bearings, seals etc. It doesn't leak a single drop of oil and it's 2 decades old with over 1/4M miles on it.

The reason I ran it was because dad buys it in 250 gallon totes for his business and he always gives me some...
 

SnowDrifter

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Oil pressure isn't everything. To a point, flow is better than pressure. Thicker oil just makes the pump and filter go into bypass sooner, giving you more unfiltered oil(oil filter bypass) and less flow at higher RPMs(oil pump bypass)

What is your oil pressure? How are you measuring it? My recommendation would be to find the source and fix that vs. tossing thicker oil in it, which won't fix said issue.

About the only time I am in favor of running thicker oil is in an engine end of life scenario where you need to get it through the next few thousand miles without throwing a rod or incurring a similar catastrophic failure that would increase your rebuild costs or shit on your core deposit. My 2 cents...
 

swathdiver

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Buick 3800

One of the best passenger car/racing engines ever produced!

Oil pressure isn't everything. To a point, flow is better than pressure.

The aluminum truck LS engines flow 1/3 more oil per revolution and their relief spring is 33 pounds.

As for diesels and cats, old guys aren't used to hearing that. There was a time when diesel exhausts flowed free and their oils did indeed harms cats if used in gasoline engines.
 

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