M1 Experiment in Tahoe V8

[Indydriver]

My 2007 Tahoe 5.3 specs 5W-30. It sits outside in Indiana winters so I ran M1 0W-30 this winter. It burned a quart of oil during a 7000 mile OCI (20% left on OLM). The truck had 110,000 miles on it at time of OC and has no apparent leaks. I decided to try something stouter within the M1 family.

When comparing specs provided by XOM, there is a huge variation in Phos and Zinc among the 30 wt oils. To refresh everyone's memory, here's how BITOG describes the function of these additives:

"Phosphorus
Used as an anti-wear, anti-oxidant, extreme pressure, and corrosion inhibitor additive. Concentration levels vary greatly depending on oil brand.
Zinc
Another anti-wear, anti-oxidant, and corrosion inhibitor additive also commonly found in bearing alloys. Concentration levels vary greatly depending on oil brand."

XOM claims the following Phos/Zinc content: 0W-30 = 650/750; 5W-30 = 800/900 (+23%/20%); 5W-30HM & 10W-30HM = 1000/1100 (+53%/46%).

That's a big swing in "anti-wear, anti-oxidant and corrosion inhibitor additive". I note that the HM loadings are the same as M1's vaunted 0W-40 product. Surely, a 50% increase in these important additives has an impact over the course of an OCI.

I chose 10W-30HM as my replacement oil which also has significantly higher viscosity than the other 30 wts at 40C and in the 150C HTHS test. It seems to me that this oil should be much "tougher" than AFE at least in terms of consumption. We shall see. Comments?

 

[JHZR2]

The viscosity may affect consumption, the zinc not... the downside of the higher zinc/phos is that if you're still consuming, you're killing emission equipment that much faster...

 

[KL31]

Was SN oil even around in 2007? The car would have been designed to be used with higher zddp SM oil. Interested to see your results on oil consumption.

 

[SteveSRT8]

We use Maxlife to great effect here on older GM V8's, generally well after 150k miles or so.

I would expect this to reduce your consumption, may take a little time if the engine is carboned up a bit...

 

[bigt61]

"I chose 10W-30HM as my replacement oil" - Probably worth the experiment, but 1 quart in 7k miles is very acceptable IMO.

 

[Indydriver]

Thanks for the feedback. Good comments.

 

[Carbon12]

With the 0W30 or the 5w30 HM synthetics have you noticed any increase in noise from piston slap on cold start up? I've been considering M1HM for my 2003 Sierra with a 5.3L but not if it makes it any noisier.

BTW, M1HM oil is now SN so Zn and P should be on par with regular M1. Using the HM 5w30 in my high mileage Cruze with good uoa results and very quiet at startup and at idle

 

[JHZR2]

Originally Posted By: KL31
Was SN oil even around in 2007? The car would have been designed to be used with higher zddp SM oil. Interested to see your results on oil consumption.



Please define "designed" to use higherZDDP SM oil... What exactly does that mean? Do you have some objective evidence that catalytic converters had higher loading to account for accelerated degradation when consuming higher ZDDP oils?

 

[GMBoy]

The BAD news is the that Mobil 1 High mileage has been reformulated and now does not have the high phos/zinc/zddp levels. It has been reduced to the same as the other M1 oils (800/900). Check their latest specsheet:

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf



Side note - 1 qt of oil used in 7,000 miles on a 100k+ mile motor is not bad.

 

[steve20]

I wouldn't want to be running M1-HM 10-30 on a cold Indiana winter morning.............

 

[yvon_la]

Aside from its anoyingly high (add name here. The oil is insane. Any synthetic from Mobil is . I use delvac le 5w30 -7 f not plugged ever . Turn the key once then I tried starting .it started right up 6 second of valve noise then boom all noise gone . Wow. My brother as a versa and someone is playing piano in there(beurk)if this oil wasn't so full of additive ? And was tested it would likely pass more standard .but then it wouldn't sell because people like aditi e even tho the oil doesn't need it

 

[Indydriver]

Originally Posted By: steve20
I wouldn't want to be running M1-HM 10-30 on a cold Indiana winter morning.............

Neither would I. Like I said, changed from 0W-30. I put enough miles on this truck that it gets 3 OCs per year so, plenty of opportunity to adjust seasonally.

 

[alarmguy]

Sounds like you have a plan, one other option that many overlook, since you are now into the 10/30 camp you can look into the 10/30 HEDO Diesel/Gas rated oils from Rotella, Mobile, Valvoline, Delo. They are called "Diesel" on the label but if you look at the API on the back it will be certified SM or SN for gas use as well.
I havent check the zinc content in that weight but it would be easy for anyone to do. I use a 15/50 and I think you have to be careful in the 10/30 range and avoid an "SN" not sure.

 

[alarmguy]

Today is your lucky day, someone just posted this VOA on what I was talking about above.

Rotella VOA 10/30 Click here

 

[Kuato]

A good experiment; subscribed to see what happens. I'll bet that the consumption goes down somewhat. It may not be applicable today since formulations change, but I experienced a bit more consumption with M1 0w30 in an experiment I did a few years ago.

 

[Nickdfresh]

Originally Posted By: bigt61
...1 quart in 7k miles is very acceptable IMO.


This. I wouldn't even worry about that but if you continued to use M1 0W-30 AFE consumption may have trended down after the initial OCI...