I've never gone nearly that long with anything I've owned... and, never will.

 

Please let us know what product you engineer so we can avoid. In my company Marketing defines a product, sets a price target, and does promotion. Engineering designs and builds the product to the best of their ability within time and cost constraints. Sure OLM is set to lower warranty costs but doesn't lowering warranty costs imply longevity? Or is you thinking "get the suckers past the warranty and then who cares if anyone ever buys our product again?"

 

The latter. No different than BMW giving free oil changes every 10k to 12k miles with the resulting adage don't buy a used BMW out of warranty due to minimal maintenance.

GM is all about money. Thus yes they limit warranty claims and couldn't care less about afterwards because repairs result in more money. If you think their engineers aren't overruled by management or bean counters, that's your choice.

 

Hmm, my wife has her 4th BMW X5 SUV just delivered to the local dealer, a 2025 PHEV. The prior 3 were required to come in for service after 12 months as she does not come close to 10,000 miles/year. BTW, free for the 1st 3 years. In fact her current 2021 X5 SUV has 21,000 miles total (It's going to daughter in OH!)

Your understanding of how a company succeeds and their view of customers is totally distorted!

 

Yeah. The Powertrain warranty expires at 50000 60000 miles. If all one wanted to do was guarantee no engine issue until after 50000 60000 miles, then I think one could go a lot longer between oil changes than 7,500 miles and 1 year. And 7,500 miles is the longest interval - it will sometimes indicate a change sooner than that. Perhaps, they consider 100,000 miles since they also sanction the PPP which can go as far as 100K miles.

And then you have those that argue that the oil change interval is too short and the one year thing is a "money grab" - and selling all that Mobil 1 Supercar motor oil is a GM money grab - so why not recommend more frequent changes then.

While I have no proof - I believe that the OLM, and result it produces, is designed to indicate an oil change before the additive package has deteriorated to the point of being ineffective. And I think its very likely conservative. That is, its not designed to go to the point of depletion - but rather indicates an oil change with significant margin built in. Would changing oil more often help? Well, analysis on this forum has shown, in some cases, early contamination - but later changes are not showing that. I think more frequent changes might prolong the engine life (they do eventually start to wear out) but I think its going to be noticed at much higher mileages. Like taking care of yourself in your youth will result in living to 99 years old versus 78 years old. You don't realize the benefit until you are really old.

 

We all paid a lot of money to get into the driver's seat of these cars, I would never moan about an oil change. I tend to let the dealer do it until I'm out of warranty then I do it myself at home on ramps and jack stands. This car does not lend itself well to jack stands because you have to remove a lot of the under-body panels to get to the jack stand locations. I did 31 oil changes on my C6 and 9 of them were done at a dealer, a couple were tied to other maintenance.

 

Prior to my C8 did ALL engine oil changes in my prior 5 Vettes. Frankly didn't trust the dealer to do correctly, especially my two drain plug dry sump C7s. Even though some on the C7 were "free," not worth the "risk" to me.

Big Lebowski showed how he lifted his C8 to remove the front calipers when replacing brake pads. He used the Jack at the round frame hole with Jack Stand at the oval lift slot. I used a similar approach when I removed my E-Ray rear tires. Actually, a bit of a reverse of what he did, Jack in oval lift slot and small base Jack Stand close to jack on frame.

Member Big Lebowski used this safe approach to remove front calipers charging to low dust pads.


Used similar approach to remove my rear E-Ray tires. Small base Jack Stand (with plastic pad) on frame close to Jack in oval lift slot. If I was going to change my own oil would use two jacks alternating lifting each side a few inches at a time, as I did my C7s. For the C8 put jack stands close to the jack but keep some tension on the jacks for more security and support.


For 7 years with my C7s used 6-inch-high homemade wood stanchions in rear and jack stands on the front cross member to make the car level to change oil. Also used the stanchions to install side skirts, splitter etc.
For the C8 only need to lift the rear as drain plug is in the front of the engine. I would make 8-inch-high stanchions to get the required height.


BTW I have 12-inch-high commercial stanchions I used when building my street rod but took a two step lift. Was worth it when I worked over a month under the car installing exhaust, trans cooler, wiring, fuel lines etc. BUT higher than needed for a C8 oil change. You can purchase plastic stanchions 10 inches high. For the C8 and now E-Ray, I found a great C8 Tech at a dealership that provides discounts on fluids and parts. I'll leave my oil changes to my 24-year-old street rod!

 

I've got more than 1,000,000 miles in Corvettes (8) over the past 34 years and all of them have been essentially trouble free. I follow Chevy's/GM's maintenance schedule.
Followed Porsche's schedules with four (4) Porsches.... more than 300K miles - zero problems
Had my Ferrari 11 years, 60K+ miles zero problems

 

This is how I always feel after reading "Best Oil or Oil Change Interval" threads.

 

Generally I believe the oil life monitor like I believe in the tooth fairy.......I change mine every 5k whether it needs it or not...I run 100% synthetic all the time as well....even in the wife's Accord...Internal combustion engines thrive on cleanliness...

 

So one owner just posted that he has 80,000 miles on his C8 with zero issues. Another member has 66,000 with zero issues. If you follow the OLM you'll never go more than 7500 miles or 1 year between oil changes. Maybe less. I've not heard of a single owner reporting any "sludge" issues. When I drain my oil (according to the OLM), it looks almost new. I have 29K miles on mine in 3 1/2 years.

Find something important to worry about.

 

5 years or 60,000 miles.

 

Thanks!

 

The manufacturer, GM, recommends a 7,500 mile oil change interval. If this was too long, engines would be failing during the powertrain warranty period and GM would be on the hook to pay for replacements. Since this interval is still in place, GM must not be seeing a rash of engine failures due to not changing the oil often enough and therefore everything is OK. Don't discount the fact that synthetic oils have longer lifespans and are more durable than conventional motor oil.

 

Hmm, nope GM recommends only ONE THING as when to change engine oil and filter, the OLM! NOT miles, NOT one year! Yep, miles and 12 months is what it said for my 1988 and 1993 Vettes before there was an OLM as those, AT BEST, were POOR INDICATORS but all we had.

The GM engineers who developed the OLM measured wear and other additive depletion and use that info in their complex, OLM algorithm. They monitor engine oil temps after cold starts. The OLM uses total engine revolutions, number of starts, miles etc.

IF IT JUST USED MILES AND KEPT TRACK OF CALENDER MONTHS (which some mistakenly think that is all it does: ) It would say as my 1993 Vette Owner's Manual before the OLM and why Jiffy Lub, some Dealers recommended with stickers they put on the inside upper corner of your windshield AS GM NOR JIFFY LUB OR DEALERs DON'T KNOW HOW YOU DRIVE:
So the OLM would say as my 1993 Vette Owner's Manual recommended (see Pic)
CHANGE OIL EVERY 3 MONTHS OR 3000 MILES, WHICHEVER OCCURS 1ST!

 

Have owned several corvettes over the years and always went by the oil % indicator based on time and mileage and have never had a problem. You can believe whatever you want and everyone has an opinion.

 

That's right! None of the manuals (2020-2025) say to change the oil at 7,500 miles. Like you said, they say to change the oil when the the Change Oil message appears on the DIC, but at least once a year. The bulletin at this link, dated 2024, says the OLM has been in all GM cars since 2010, and it also says that since 2013 the OLM was capped at 7,500 miles and 12 months in all GM vehicles except Volt. Volt is 2 years but unlimited mileage.
https://static.nhtsa.gov/odi/tsbs/20...02441-0001.pdf

I do not know when the OLM first appeared in any GM cars, but the technical papers by the inventors of it go back as far as 1987.
http://profiles.sae.org/shirley_e._schwartz/



For those that don't like to click on links, here is what the bulletin says about the algorithm:

"Engine revolutions – Oil life starts with a fixed
number of revolutions and will decrease with each
revolution. Cold / hot coolant temperature readings
have multipliers that reduce engine revolutions
pathway quicker depending on how far from the
normal oil temperature the vehicle is operating.
Note: If the engine coolant temperature gets above
260°F (126°C), engine overheat condition, the oil life
will go to 0%.
2. Mileage from last reset – Starting with MY 2013,
the OLM is capped at 7,500 miles (12,070 km) for
all GM powertrains except the Volt. In perfect
conditions, a vehicle would reach 7500 miles
(12,070 km) from the last reset and the oil life left
would be 0%.
Note: For the 2016-2018 MY Camaro, 2014-2018 MY
CTS and 2015-2018 MY ATS equipped with the 2.0L
LTG sold in Europe, the OLM is capped at 30,000 km /
1 year.
3. Time – This pathway is a liner function, a fixed
decrease in oil life for a given time after the oil life
is reset. The oil life will drop to 0% after 1 year
regardless of the amount of engine revolutions or
how many miles since the reset.
4. Fuel-in-Oil Dilution - Diesel engines only – The
amount of oil dilution due to diesel fuel is modeled
based on the engine's operating conditions. As
dilution increases and approaches a limit, the
remaining life will reduce towards 0%. Drive cycles
that cause more DPF regeneration and that require
more after-treatment warm-up will increase dilution
more quickly than ones with less such events."

 

^^^
Yep, don't know the year the OLM started in the Corvette. Believe it was used in some GM cars prior. BUT know it was not used in my 1988 or 1993 Vettes.

It was in my 2008 C6 BUT did not include a calendar so had to keep track of time yourself.
My two C7s, 2020 C8 and E-Ray have the calendar and keep track of time. As the fellow who worked with the GM engineers who developed the OLM posted: It can decrease it from the Max 12 months if the OLM algorithm dictates, but nothing will increase the 12 months..

Certainly better then the "Change every 3000 miles or 3 months" the 1993 Vette Owner's Manual had to "guess" might be needed as GM didn't know how you drive! Some who used Jiffy Lub or had a dealer who used those small stickers after you had an oil change. They added 3 months and 3000 miles from the odometer reading as to when to come back! That was based on using Owner's Manual recommendations for sever servcie. Many did not understand, as my 1993 Vette Owner's Manal showed, mostly <4 miles trips, stop & Go driving is Severe Service!

As I have stated knew from the mid 1950's when my Uncle, who was Service Manger at a large Chevy dealer told me:
It was NOT miles that were important it was the type:

• GOOD HIGHWAY MILES OR
• POOR CITY DRIVING MILES

 

Well we all see how well GM recommend fluid change intervals are working for the c8 transmission...so yea GM engineering is awesome sauce. They should invent a tranny life monitor...

 

If were a hotshot driver who can easily put that amount of mileage on a vehicle in a month or two running up and down the interstate that you would change your oil sooner? Conditions don't matter?