10w30 vs 5w30

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Originally Posted By: gfh77665
Ssshhhh! Don't tell anyone, but I am running (almost free) straight 40wt. PYB in my Chevy truck this summer. MPG's, starting ease, oil pressure, RPM's, everything still the same. Remember...Quiet please!

By all means, BE QUIET! If your owners manual reads to use 5W20 and you use a different weight, you will have the BITOG 5W20 POLICE on you like white on rice!
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Its a late 90's Chevy truck, excellent condition, only 85K miles. I drive up & down I-10 everyday 80 mile round trip. It calls for 5-30 or 10-30, but the PYB 40 has worked perfect so far. Truck doesn't know the difference. I am going a 7000 mile OCI.
 
Originally Posted By: gfh77665
Its a late 90's Chevy truck, excellent condition, only 85K miles. I drive up & down I-10 everyday 80 mile round trip. It calls for 5-30 or 10-30, but the PYB 40 has worked perfect so far. Truck doesn't know the difference. I am going a 7000 mile OCI.

The truck might not know but we all now know! Keep your eyes in the rearview mirror for the BITOG POLICE!
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Originally Posted By: Merkava_4
The BITOG POLICE would flip their lid if they knew I was doing 2K OCI's.
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OMG! Are you trying to give the BITOG POLICE cardiac arrest?
 
Originally Posted By: gfh77665
Ssshhhh! Don't tell anyone, but I am running (almost free) straight 40wt. PYB in my Chevy truck this summer. MPG's, starting ease, oil pressure, RPM's, everything still the same. Remember...Quiet please!


I have Spock ears... I heard ( : < )

The part in red is impossible. A 40 grade is thicker at all temps than 5W30 or 5W20, so oil pressure will be higher at any given oil temp. It's worse with a straight grade oil. If you aren't seeing it on your gauge, it's an OE dampened gauge or one of those "idiot-lights-with-a-needle" so that it doesn't show the difference. My statement is based on physics but I have verified it with accurate gauges on two trucks. With one (diesel), when I went from 15W40 to 10W30 HDEO, there was a 4-5 psi drop in oil pressure at the same oil temp. In another (gas) truck, going from 5W20 to 10W30 there was a 5-8 psi increase.

I'm not saying that 5 psi one way or another is hugely significant on a warmed up engine, just that the difference is there whether your gauge is indicating it or not.

In Texas, you can get away with a straight grade oil more than most.

For the benefit of others, one of the disadvantages of running a heavier-than-spec'ed oil is that you will put your oil filter closer to bypass with the increased pressure of a cold start. That means you really need to feather-foot while the engine is cold because if you don't you will be blowing unfiltered oil past the bypass until it worms up and thins out. This is another thing I have verified with one of my trucks. I know the bypass cracking spec for the oil filter I use and I have a differential pressure gauge set on my engine so I can read the pressure on both sides of the filter.

I am currently running 10W30 in an engine designed for 5W20... an experiment. The cracking DP for the bypass valve in the filter I use is 8psi and I bump up against that even on a 70F start when the engine flares upon start (EFI). I have to drive really easy until the oil reaches about 150F (yes, I can also read oil temp) before I can engage in spirited driving. Even with the oil at 190F+, when I bump up against the rev limiter at 5500 rpm, I am bumping up against the bypass DP as well. I have just finished datalogging with the 10W30 and will be changing the oil back to 5W20 and doing it all over again to see wassup. Will also be testing the new DP of some popular oil filters just for grins.

And there is another price to pay for thicker-than-recommended oil and for single grade oil that doesn't flow well cold. "Cold" is relative. To the oil industry, anything under 100F is "cold" and if you look at the viscometrics of a straight 40 grade at, say, 70F, it's running at 486 cSt (40c scale, about 32 cSt on the 100c scale) which puts it thicker than 60 grade motor oil and at the upper end of 140 grade gear oil. That's at a relatively warm 70F start. I shudder to think of a 40 F start. A multigrade oil does much better.



This was a borderline hijack but I thought it was relevant to the discussion.
 
Originally Posted By: gfh77665
Its a late 90's Chevy truck, excellent condition, only 85K miles. I drive up & down I-10 everyday 80 mile round trip. It calls for 5-30 or 10-30, but the PYB 40 has worked perfect so far. Truck doesn't know the difference. I am going a 7000 mile OCI.


Are you in El Paso?
 
Originally Posted By: gfh77665
10-30 typically is a bit thicker at high temps, and is a bit more shear stable. Again, the "5" won't benefit any in this application.


This is not always true, M1 5w30 is thicker at temp than the 10w30 is. At least last time I saw the specs it was.
 
Good stuff as always Jim. So partial bypass at start up may not be as rare as we've been told when using thicker oils? Am I getting that right?
 
Originally Posted By: KCJeep
Good stuff as always Jim. So partial bypass at start up may not be as rare as we've been told when using thicker oils? Am I getting that right?


It depends, KC. My truck running one grade thicker than specs can reach the bypass threshold on a cold start, even with a fresh filter. Extrapolate to an engine using oil one two grades thicker, and a multigrade with a 100 VI... can't imagine it NOT bypassing on a cold start (again cold is relative).

I was probably the guy telling you about bypass events (it's my "thing" now), saying they are "rare." That was based on what I was told by several oil filter engineers and on my own experience/testing but I have tried to caveat that by saying, "With the correct oil viscosity." Running oil thicker than spec'ed or single grade, tosses that out the window.

I expected to see lot's more bypass events on my truck (running more than one grade over spec) but I have to have caution in the way I operate it to prevent them. Within a few days, I'll have 5W20 in it again and can see how it works with the right viscosity. My first test filter will be the Ford-spec'ed FL820s.
 
Originally Posted By: larryn
10w30 vs 5w30 when towing in hot weather 95/100F , oil will be changed after 5000 to 6000 mile 6 week trip.oil is quaker state UD.truck is an 09, 6L 1500 silverado.trailer is approx. 6800#.


yes, I mean no, I mean it depends, err...

Check the 100 degree viscosities to answer that question
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A 0w30 might be the best choice... all depends on the product and it's specs.
 
Of the 3 M1 xW30 grades, looks like 5W30 is thinnest at starting temperature (at least in So Cal), but it's thickest at operating temperature.
 
Originally Posted By: jimmy87
Originally Posted By: gfh77665
Its a late 90's Chevy truck, excellent condition, only 85K miles. I drive up & down I-10 everyday 80 mile round trip. It calls for 5-30 or 10-30, but the PYB 40 has worked perfect so far. Truck doesn't know the difference. I am going a 7000 mile OCI.


Are you in El Paso?


Opposite corner of the State. Near Beaumont TX.
 
Originally Posted By: Jim Allen
Originally Posted By: gfh77665
Ssshhhh! Don't tell anyone, but I am running (almost free) straight 40wt. PYB in my Chevy truck this summer. MPG's, starting ease, oil pressure, RPM's, everything still the same. Remember...Quiet please!


I have Spock ears... I heard ( : < )

The part in red is impossible. A 40 grade is thicker at all temps than 5W30 or 5W20, so oil pressure will be higher at any given oil temp. It's worse with a straight grade oil. If you aren't seeing it on your gauge, it's an OE dampened gauge or one of those "idiot-lights-with-a-needle" so that it doesn't show the difference.


I am not sure about the ears reference, but, as far as I can tell, any pressure difference is beyond the sensitivity of the stock gauge. I think it reads pretty well, as it responds quickly during acceleration, etc. So, if it is too small to register, for all intents and purposes, I say “no change” in pressure. I would note I was watching for it, too. I was a bit hesitant to experiment at first, but am glad now that I did. My truck starts, runs, sounds and performs the same as it always did with 5-30 or 10-30.
 
Originally Posted By: Blue_Angel
Mobil 1 @ 100C, 40C, VI, 150C (Canada):

SN SN SN
0W-30 5W-30 10W-30
10.9 11 10.1
62.9 61.7 63.2
166 172 146
3 3.1 3



Where exactly are we finding M1 0w-30 in Canada?
 
Originally Posted By: Jim Allen

I have Spock ears... I heard ( : < )


I grew up with Star Trek in the '60s... "You were so worried about his Vulcan eyes that you forgot about his Vulcan ears!" Referring to Spock's super sensitive hearing. I forget not everyone is as gray as I am.

Originally Posted By: gfh77665

I am not sure about the ears reference, but, as far as I can tell, any pressure difference is beyond the sensitivity of the stock gauge. I think it reads pretty well, as it responds quickly during acceleration, etc. So, if it is too small to register, for all intents and purposes, I say “no change” in pressure. I would note I was watching for it, too. I was a bit hesitant to experiment at first, but am glad now that I did. My truck starts, runs, sounds and performs the same as it always did with 5-30 or 10-30.



As to the rest, I reserve judgement because essentially you are asking me to believe the sky is green. The oil phenomenon I described is universal physics. I wouldn't think the truck runs any differently but you can bet your oil filter is in bypass a lot more... which is not something to be glad about IMO. Especially since there is no benefit to running an oil that thick if not dictated by circumstances.

I'm all for free, so I understand why you are using it. I might be tempted too. I'm only gnawing on this because you are trying to make it sound optimal... and it's far from it.
 
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If you have been running the 40WT for a few oil changes a UOA would be interesting. I would expect to see high levels of wear metals.
 
Originally Posted By: Jim Allen

essentially you are asking me to believe the sky is green..... oil that thick if not dictated by circumstances.

I'm only gnawing on this because you are trying to make it sound optimal... and it's far from it.


I am offering a anecdotal commentary of an experience of mine, nothing more. I do want to say "for the record" I am definitley not advocating 40 for the masses. I have no reason to. In TX, with 100 degree temps and 100% highway (minimal cold starts) the 40 is working well for me.

Yes, in an analytical sense, it is thicker and causing higher oil pressure. In a real world sense, no perceptible difference. It not "optimal", but it is definitly OK. I will not use it in the winter, nor in a newer car like my 06' Honda.

The sky is blue, my truck is running well, and I know who Spock is.
 
Originally Posted By: gfh77665
Originally Posted By: Jim Allen

essentially you are asking me to believe the sky is green..... oil that thick if not dictated by circumstances.

I'm only gnawing on this because you are trying to make it sound optimal... and it's far from it.


I am offering a anecdotal commentary of an experience of mine, nothing more. I do want to say "for the record" I am definitley not advocating 40 for the masses. I have no reason to. In TX, with 100 degree temps and 100% highway (minimal cold starts) the 40 is working well for me.

Yes, in an analytical sense, it is thicker and causing higher oil pressure. In a real world sense, no perceptible difference. It not "optimal", but it is definitly OK. I will not use it in the winter, nor in a newer car like my 06' Honda.

The sky is blue, my truck is running well, and I know who Spock is.

But, your Honda can go as many OCIs on the same filter as you want.
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