[rockhoundrob1]

New here (Well, new to this portion of the forum).

Just got a 2014 XTS 6 cyl. 61,000 miles.
I know the guy before me took the car in for oil changes. His Cadillac place I assume used synthetic oil. It has 38% oil life left.
I plan to change it when it drops to 15-20%. I use Phillips 66 synthetic blend (5w-30), but I have no idea whether it's 10%, 30% or 50% synthetic- or whatever.

My question is, does the car know whether I use 100% synthetic oil or conventional? If not, how does it decide how much life is left?
FYI, when I drive to work - it's about 80% highway driving 70 miles daily - 5 days a week. So surely I can get around 7,000 -8,000 mile between oil changes.

Any recommendations?

 

[Mr Earl]

Here are some oils that meet the dexos1 spec. Apparently it does not have to be full synthetic. The oil life is calculated by an algorithm that includes engine revolutions, engine RPM history, temperature, etc. to asses how worn out the oil is. I don't think it cares what oil, as long as it is dexos1 spec.

SIDEBAR:

Partial List of Motor Oils with the dexos Icon and Trademark

CarQuest Synthetic

Castrol Edge Professional

Mobil 1

Mobil 1 Extended Performance

Pennzoil Synthetic Blend

Pennzoil Platinum Full Synthetic

Quaker State Synthetic Blend

Quaker State Ultimate Durability Full Synthetic

http://www.hendonpub.com/police_fleet_manager/articles/2012/1112/dexos1_motor_oil_required

Mr Earl

 

[Submariner409]

The OLM algorithms are developed using the recommended engine oil for the particular car year/model/engine. Time, revs, operating temp, air temp, speed, load, coolant temp, dozens of other conditions.

This is from the Cadillac Forums Technical Archive articles on the Northstar System - it's about the late 1990s - 2000s OLM but you get the idea. Don't sweat the oil type - drive the car. The OLM has huge safety factors built in.

https://www.cadillacforums.com/cadillac-tech.html#oillife

Almost every automotive engine oil on earth met the DEXOS-1 spec before it was ever published - it's a minimum oil performance specification, not an oil formulation by GM. To get the "approved" label GM forces oil companies to pay a licensing fee. Scam, big time.

Get into the Shell (SOPUS - Shell Oil Products, U.S.) white papers. Royal Dutch Shell produces Shell, Pennzoil, Quaker State, other engine oils.

 

[Cutlass]

It does not know what oil is in it nor does it measure the oil quality in any way. It doesn’t know if you are using full syn, old school conventional, veggie oil, or if an angry ex-girlfriend dump her water bottle out in the engine. It’s just a decent, engineering calculation.
Ultimately it’s up to you make sure the oil in there is good.

 

[jghiller]

I personally since the days of the 2nd GEN CTS have always used full synthetic and back in 2008, Mobil1 5W-30 was recommended and it was even displayed on the oil fill cap. I never wait for the OLM to tell me when its time to change the oil. I do not ever let the percentage go below 30% but thats me. It doesnt cost much to make sure your oil is always well maintained. The algorithms for the OLM as described above are likely affected by the quality of oil used. As long as you make sure the brand you choose is FULL synthetic, you will be OK. Confirm that it has the DEXOS1 spec on the label. And I always choose a Top Tier gasoline in my XTS, if possible.

 

[rockhoundrob1]

OK thanks guys! Will make sure to look for the DEXOS1 !!

 

[hojokalet]

I prefer to use Mobil 1 oil in all my cars. I change the oil when the indicator is roughly 5%. At 100K miles the car does not burn oil between oil changes. Mostly highway driving. Note that synthetic oils tend to be a bit thinner than the blend or regular oils and may have higher oil consumption and/or gaskets may leak a bit more as a result. They will protect your car's engine better for startup and when at operating temperature.