Mobil 1 shear issues

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I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?
 
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It would be difficult to tell simply on your oil pressure gauge what’s going on. However, it’s doubtful Mobil 1 has premature shearing issues.

Without raising red flags:

1. Depending on your oil change intervals and your dealer re-order intervals, along with their supplier’s re-order intervals - you could be seeing the beginning of the Dexos 1 Gen 3 additives. Or, potentially on your second oil change with this, as some of it came live as early as last November.

2. Your dealer could be using something different than Mobil 1. There have been continued additive shortages in the pcmo market for the last 16-18 months. It is regionally - and marketer - dependent. The latest is Afton going down, again.

Your dealer may, or may not be aware of any changes to the formulation they’re purchasing. However, I would assume it’s PQIA in spec and/or a Dexos licensed product.

More… not good things.

1. Wrong oil was used. Only way to tell is a UoA.

2. Oil wasn’t actually changed.

3. Other issues, including mechanical, dealer, etc.


But if they’re using factory sealed - or even distributor (hopefully MOM approved) supplies oil, I would safely guess that Mobil 1 doesn’t have a premature shearing issue.
 

OVERKILL

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I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?
The oil they are using is probably heavier.
 

CKN

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I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?
As a three time Silverado owner (5.3) I can tell you these motors require very little oil pressure to function. I tow several thousand miles a year using the 0W/20. I don't worry about fluctuation in oil pressure-high or low. I would be more concerned about transmission temperatures.

Zero oil pressure would be another story!
 
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I noticed that my oil pressure gauge stays right at 20 psi hot idle after going to PP 0W-20 this last OCI. I was always using M1 AFE or EP 0W-20 and at hot idle it would be a little below the 20 psi line. I know the gauge isn’t super accurate, but there is a difference on my truck.
 
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unless your vehicle calls for Mobil 1 and was changed at a GM dealership, they should have used whatever type of oil is called for by the manufacturer...GM dealerships have been using Mobil oil products for some years now and their bulk is most likely Mobil Super Full Synthetic if your call is for a Dexos oil...

Bill
 
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I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?
Most dealers that carry M1 oils have in by the barrel.
 
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Higher oil pressure at hot idle after being serviced at a different location does not indicate an issue with your previous services/materials. A little change in the pressure gauge should not be a concern as long as it's well inside the normal range... I'm curious how much higher the oil pressure actually is for you now. Towing definitely qualifies as severe service, so just keep up with regular maintenance as needed and don't worry about it. Many friends have taken their Silverados well over 200k miles with hard use and very few issues... they just did basic maintenance and addressed those few problems as they came up. Enjoy the truck.
 
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I recently had my silverado serviced at the dealer after using Mobil 1 and ac delco filter for the past couple years. I notice my oil pressure isn’t running as low at hot idle after towing in the summer. Not sure what kind they used but I can’t imagine it would be anything other then bulk oil. Does Mobil 1 have issues with shearing or something I’m not aware of?

If I had to guess it's probably just the filter they used. I use mostly AC Delco's on mine but have used Purolator Pure One but currently using Fram Ultra. I've never experienced pressure differences between the different filters but it certainly is possible. It could be a difference in the oil they used, you'd have to check with them and see what they put in there, but any oil when it's fresh and new will be very resistant to shearing which would translate to higher pressure.
 

ZeeOSix

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If I had to guess it's probably just the filter they used. I use mostly AC Delco's on mine but have used Purolator Pure One but currently using Fram Ultra. I've never experienced pressure differences between the different filters but it certainly is possible.
If the PD oil pump isn't in relief, then the oil pressure isn't going to be effected by the oil filter. No engine puts the oil pump in relief at idle and low RPM unless the filter is completely clogged and the filter bypass valve is overwhelmed ?highly unlikely). At near redline with not fully warmed up oil, it's certainly possible to hit pump relief.

It could be a difference in the oil they used, you'd have to check with them and see what they put in there, but any oil when it's fresh and new will be very resistant to shearing which would translate to higher pressure.
Of course the viscosity (when at a constant temperature and engine RPM effects oil pressure. The HTHS viscosity is what really correlates with oil pressure. The difference in the oil is what caused the difference in the oil pressure.
 
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unless your vehicle calls for Mobil 1 and was changed at a GM dealership, they should have used whatever type of oil is called for by the manufacturer...GM dealerships have been using Mobil oil products for some years now and their bulk is most likely Mobil Super Full Synthetic if your call is for a Dexos oil...

Bill
My GMC dealer in Pompano Beach only uses AC Delco oil. They do not have Mobil oil. My Chevrolet dealer in Paramus New Jersey does have Mobil oil besides AC Delco. I get Mobil 1 0w20 when I am at that dealer.
 

ZeeOSix

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Of course the viscosity (when at a constant temperature and engine RPM effects oil pressure. The HTHS viscosity is what really correlates with oil pressure. The difference in the oil is what caused the difference in the oil pressure.
As a follow-up, here's some data that was provided by someone here (I don't recall the BITOG member) quite a while ago, and I ended up plotting the oil pressure vs the KV100 and HTHS viscosity. Look how the oil pressure is more of a direct function of the HTHS viscosity than it is of the KV100 viscosity.

1661977025439.png
 
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My GMC dealer in Pompano Beach only uses AC Delco oil. They do not have Mobil oil. My Chevrolet dealer in Paramus New Jersey does have Mobil oil besides AC Delco. I get Mobil 1 0w20 when I am at that dealer.
since about 2017, AC Delco oil is made supplied by Mobil...unknown what level of Mobil synthetic (some have speculated it is Mobil Super synthetic) unless it specifically is listed as something else...

Bill
 
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since about 2017, AC Delco oil is made supplied by Mobil...unknown what level of Mobil synthetic (some have speculated it is Mobil Super synthetic) unless it specifically is listed as something else...

Bill


Not all of it is made by Mobil anymore.
 

4WD

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does GM use any AC Delco Dexos 1 Gen2/3 oil currently???...I didn't know that

Bill
Last I knew - P66 made the normal stuff - M1 for the high end - Delvac for DMax …
BTW: I find the title misleading … not going to see minor viscosity changes on 100 psi gauges
 
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ok...round here all I see is Mobil (not Mobil 1 unless you pay the uncharge) lubricants...but that is for the Dexos 1 oil products as well as transmission and differential fluids...

thanks

Bill
 
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