Oil change frequency

I recently bought a 2011 Cadillac CTS coupe with 17K miles on it 3.6l v-6. I have put 3k miles on it and am thinking about an oil change. I looked in the owners manual for recommendations and it says change the oil at least once a year or when the computer monitoring system gives a message that your oil life is low. I’m wondering specifically how the system detects when an oil change is needed, and is a gimmick or should I change oil every 5k regardless like I have been doing for 30 years? The monitor says I have 70% oil life left which would mean about 10k per oil change (no need for synthetic according to the manual). By the way, I love the car and it’s the first car I’ve owned with XM radio (I’m hooked) and the first premium sound system, what a difference.

Personally, I’d change it now, since you can’t be sure of its history, and again every 5,000 miles. Not only will your car benefit from always having fresh fluids, but you’ll sleep better.

I agree–as I usually do–with mountainbike.
However, I want to add another thought:

That oil life monitor is supposedly accurate enough in detecting engine temperature, drive cycles, and other factors, so that it won’t put your engine in danger of sludge and other lubrication-related problems. In my opinion, that type of extended oil change interval is probably fine for people who get rid of their cars every few years–before lubrication-related issues arise.

If you are planning on keeping this car for the long term (as both mountainbike and I do), you would help to ensure the life of that engine by doing oil changes every 5k miles. Also–don’t forget to lift the hood every few weeks in order to check the level of the oil and other fluids.

If you intend to keep this car for the long term, you shouldn’t rely on others to do fluid checks, and you certainly shouldn’t wait until the next oil change to find out that you were driving with a low oil level. Aim to never allow the oil level to fall more than 1 qt below the full level.

Based on the Oil Life Monitoring (OLM) system the oil change frequency on my 2010 Cobalt and 2013 Equinox is ~9k and 7k miles respectively. I’ve decided to stick with a 5k change interval as it’s easy to remember and it’s what I’m comfortable with. Prior to this I changed the oil at 4k intervals.

Last year we had a poster with a Traverse with the 3.6 that had a sludge problem following the OLM recommended interval and not checking the oil level between changes.


Ed B.

GM OLMs are quite good, they account for the type of driving, temperatures, etc. They do not actually measure oil condition, but they record the factors that affect it. Me, I’d change it now to make sure it’s fresh and correct, then I’d follow the OLM.

And make sure you use the correct grade of oil, GM has a new requirement out for some of their engines.

I agree with @missileman and @VDC driver. GM’s oil life monitor is very good, industry best. Do a change now and then use the OLM to tell you when its time. I prefer synthetic oil changed when the OLM says so. I’ve got a GM truck I’ve owned since new that has 108K on synthetic changed that way. The motor is still very strong and uses 1/2 quart every 5000 miles or so.

Thanks for the vote of confidence @Mustangman but if the truth be known…I would still change my oil at 5K as @mountainbike suggests even if I owned a vehicle with OLM. I’m not a big fan of unproven technology.

The GM oil life monitoring system is the best out there. It’s not just a “timer.” It’s an algorithm that factors in ambient conditions, driving patterns, start/stop cycles, and measures crankshaft revolutions to determine the oil life.

Having said that, the system is dependent on 2 things. Using a quality oil filter and the proper motor oil, and keeping the oil full. For the 2012 model year and newer GM requires a synthetic blend oil called “dexos”. I keep this in stock and use it in all GM cars with an oil life monitor for 2010 and newer. I also use AC Delco oil filters. The difference in price for dexos vs. conventional oil is a buck a quart. No big deal. You still need to check it regularly and add as needed. You can easily run your engine out of oil in 10,000 miles if you never open the hood to check it.

Footnote: Some 3.6 engines had problems with premature timing gear wear, and a software update was issued to reprogram your oil life monitor to a shorter change interval. See your GM dealer and ask if your car has the latest updates.

I like the 5K system for keeping track also. My last vehicle (2000 Taraus) went over 200K with zero major engine problems using that philosophy. . I plan on keeping this car for 10 + years so I’ll schedule an oil change. Thanks for the note on the 3.6 recall, I’ll check it out.

I agree with the other posters. I would go 5000 miles regardless of what the monitor says. Just think, even if you had water in the crankcase the monitor would still go to 10.000 mile or so. if I did nothing but highway driving at moderate speeds, the higher figure would be OK.

You might want to recheck what your owner’s manual says about oil type. Your post says quote:" (no need for synthetic according to the manual)" Unquote, copied and pasted.

Our 08 GM car (traded in for a '13) with a 3.6 V6 specified synthetic per GM4718M as does our 09 GM car with a 2.2 liter four which also specifies oil per GM4718M such as Mobil 1 or equivalent. It goes on to say: Oils meeting this standard may be identified as synthetic.

That leaves the door open to use a non-synthetic or a blend if it meets the GM4718M specification but there is no wording that I see that says “no need for synthetic”. Later on, for certain by 2013 GM changed to specifying oil designated “dexos 1”. You might do well to use GM’s latest oil specification.

I use the GM oil monitor but change the oil and filter when the remaining life is below 10% or at least once per year in any instance. I believe that GM is interested in your and my satisfaction with their cars and has thoroughly tested their oil countdown program. It’s been around for several years now and I have seen no feedback to prove that it does not work well.

I looked at the owner’s manual online. It is crystal clear that oil meeting dexos specs must be used

I wonder if the shop is using such an oil?

You know, there is legislation afoot (I think maybe enacted) that requires a specific part number for every item sold for auto service. So the lube shop can’t just write 5W30. They would have to use “10-9050” as the part number for dexos. This is to ensure that the proper lubricants are being used to maintain warranties and provide proper engine protection.

No one seems to think that what’s on the invoice and what goes in the car may 2 different things.

We use the OLM in our Olds van and there are no oil leaks after 150,000 miles. GM has been selling cars with the OLM for 35 years and there has never been a class action suit that would make the shysters rich. In short, it works. Change your oil between 25% and 20% life remaining. I have absolutely no reservations about using the OLM to determine oil change frequency. The state of California even uses the OLMs to determine when state vehicle oil gets changed.

Those oil change monitors are a boon to mechanics boat payments. I"ve heard tale of a lot of engine change-outs due to owners following the recommendations of the electronic oil monitor. I’d just do what you’ve always done, 5,000 miles – provided that has worked well for you in the past. Of course if you don’t follow the manufacture’s recommendation to the “T”, you may void the warranty, if that is an issue.

“mechanics boat payments.”

That is such a ridiculous, and often incorrect, phrase

What percentage of mechanics do you suppose actually have a boat of any kind?

How did that even get started?


lol … hey, isn’t that the phrase Tom and Ray use? I think THEY started it! lol …

Here’s a good link on oil change interval common sense recommendations.


Mechanic’s boat payments started many years ago with Tom and Ray the tappet Brothers. Where have you been?


I’ve been listening to the show for many years . . . as all of you guys have!

That said, I didn’t know they started the phrase themselves

Since there are many phrases in regards to shady mechanics . . .