Questionable OCI indicator on GM trucks

[Jim Allen]

Originally Posted By: The Critic
Originally Posted By: Jim Allen
If you install oil better than the calibration oil then you have some built in leeway. If you install lesser oil, you go in the opposite direction.


Depending on the specific circumstances, all oils will be the same. All oils will pick up contaminants (blow-by and fuel dilution) at the same rate. Also, all oils likely contain about the same amount of anti-wear additive as well, due to the API and ILSAC regulations. Therefore, the only real differences between most synthetic oils and conventional oils are the slight improvement in oxidation resistance with synthetic and the added detergency in certain brands, which may or may not be useful. Therefore, based on those assumptions, oil life is going to be the same.


I think you may be minimizing the differences in oxidation resistance but there are so many aspects that muddy the waters, you are probably correct in most cases. The only way to know would be to run some significant tests. Another point that I didn't consider is that, from what I see, GM is using some pretty decent oils for FF these days, thus narrowing any possible gaps.

 

[webfors]

How many quarts does she take for a full oil change? If it's 6-7 quarts I wouldn't worry much about using dino.

If you're using M1 you are adding an extra buffer so why not follow the OLM?

 

[901Memphis]

Grab some Pennzoil Platinum / PU/ M1 Truck and SUV, whatever your favorite synthetic is, follow the OLM, and you will still have plenty of life left when it runs out, change it and sleep well knowing your engine will stay factory clean if its there now.

 

[Corvette Owner]

THIS is exactly why you run a UOA ! Follow a lot of people's advice and do an UOA at 10,000 miles than 15,000 (if it looks good at 10,000) and answer this question for yourself.

That said, I believe in OLMs, especially GM's. AND as said before, using synthetic gives you an additional "buffer".

 

[Durango]

Originally Posted By: paulswagelock
My 2010 Tahoe has the oil life indicator. Based on my driving conditions, it regularly call for a 15,000 mile OCI. I am all for extended intervals, but 15,000 miles on dino oil? So far I have completely disregarded it and changed every 6000-7000 instead (Mobil 1).

Does anyone think this thing should be followed? I am sure there is a complicated algorithm running in there, but 15,000?



paulswaglock,

In my Impala is use the OLM myself so in your case I'd just fit the largest oil fileter on it that prcatibal and then start using an extended synthetic like the toehrs have said.

If you go that route I'd then change it out annualy every December-January.

It not unusual these days to have a car/truck to have such an oil change schedule. Take BMW for instance.... They have annual oil changes every year as standard. A fried of mine does this on his BMW and the dealership won't change it until a certain amount of miles passes on the odometer. They use only synthetic oil.