I have around 6800 miles on my '08 so far. The oil life monitor is reading around 50% life left. I drive about 1500 mi/mo with about 70% highway/30% suburban stop-and-go traffic. I have owned many GM cars with oil life monitor and use it religiously to not have to change oil any more often than necessary. However, at this rate, I may not need to change the oil until around 13,000 miles, which makes me a little uncomfortable. Anyone else seeing this?
I don't recall my '03 CTS being this long between oil changes, even though it also used synthetic oil. With the same driving patterns, I seem to recall getting around 7500-8000 miles between changes.
Anyway, just curious. I'm keeping a normal check of fluids including oil, and so far everything is looking normal.
from what I can gather the gm spec for synthetic oil in the new v6 - gm4718m - has tougher standards than the old one - gm6094m.
maybe the longer oil life for the 2008 is based on using the better oil.
rg
I have never worried about oil life since synthetics came out. I believe even the early stuff could do 10,000 miles with no excess wear and today, I would feel comfortable with 15,000 miles of mixed driving.
But.
As to the filter............
Bottom line: if you are not going to keep the car beyond 50,000 miles, or so, I would go with the oil life monitor.
If you are going to, or might, keep it for 100,000 miles or more, I would establish an interval.
I personally am going to change oil and filter when the Oil Life Monitor reaches 50%.
That's just an arbitrary decision.
I DID change oil for the first time @ 1400 miles.
Just an old habit concerning breakin.
I have never lost an engine in 55 years of driving. Why would I change?
While we are on the subject of maintenance, how about the rear differential lubricant? I didn't see anything on this in the manual. The only RWD vehicles I have owned in recent years were GMC pickups and in each I changed the original lubricant at about 1,000 miles and it always had quite a bit of metal "shavings" on the magnetic drain plug along with a sheen to the lubricant. The rear ends on the pickups tend to get very hot during early break-in which is one of the reasons for varying the speed and avoiding high speed driving. Obviously these are different units (the pickups are a much larger assembly with an Eaton "Gov lock" instead of the traditional limited slip unit) from different makers but I am curious if anyone else has changed the rear axle lube and if these have a drain plug or require case removal like the older GM passenger car units.
Back on topic, my plan is to do a oil and filter change at around 1000 miles. In recent vehicles I have used the OLM system but I generally change at around the 50% mark without resetting and then change again when it approaches zero life remaining. The exception has been my 2006 pickup because at around 7,000 miles (using the recommended conventional 15W40 oil) it generally still shows over 60% life remaining and that seems like pretty high mileage on conventional oil; especially since diesels also have EGR now.
I have a 3 year lease so I'm going by the OLM. however I did change the filter element at 4k miles just in case there was any debris from mfg and break-in. didn't see any but I feel better nonetheless and changing the filter is real easy. topped off the oil at 4k and again at 8k, with the total added being one quart.
If I owned the car I would consider maybe 8-10k mile intervals, and probably do the first one at 1-2k. even if you don't keep the car for 100k+ miles it is a selling point that you took good care of the motor.
rg
At the dealership when I brought it in, they told me it should be changed every 5-6k, however their reasoning is that the DIC tells you oil LIFE but not oil LEVEL...so, to be sure, you should check your oil level and if its fine, then you can hold off on your oil change, otherwise, you can add a bottle of mobil 1 or something to make sure your oil level is fine
If anyone is interseting in doing their own oil changes, see the attached link. I did the first one at 5K and will end up somewhere around 7500 miles between changes - same as my 2005 CTS.
