Do you trust "Oil Life" gauges?

We bought a used 2014 Grand Cherokee and the window sticker says an oil change in 700 more miles (out of 3k miles) but the Oil Life gauge says it has 72% oil life remaining.

Who do you trust? I would guess the used car dealership didnt use synthetic oil when they changed it, but does the 3.6 pentastar run clean enough to push the oil life three times the norm for dino oil? What is the gauge showing me? Milage count? Electrical resistance? Optical sensor?

What does the book say for oil change intervals?

I suppose thats the right answer.

oil viscosity sensor is most likely used so yes you can trust the dash

http://www.sensorsmag.com/sensors/solid-state-acoustic-wave-viscosity-sensors-the-future-oil-c-1428

Jeep is probably recommending 10K intervals (to keep maint. costs down) and the Lube shop is recommending 3K intervals (to keep money flowing in to their shop). Somewhere in the middle is the correct answer.

I sent the oil on my truck in for analysis a couple (three?) times. I changed it based on what the computer said between 9k and 10k miles. It always came back from the analysis with a recommendstion to run it 3-5k longer. I trust the oil life monitors.

I'm trusting the oil life computer in my Corvette because it takes into account multiple factors like temp and RPM. In my Tundra I go 10k or 12 months. I always hit 12 months first. My Tundra doesn't have the computer or else I would probably follow that. Come to think of it, I changed the oil in the Corvette this spring and it is around the 50% mark on the computer. Now that winter is here and track days are gone I'll probably just change the oil in the spring before my next track day.

I usually trust mine. GMs are pretty good about mapping the whole driving style (TPS, coolant temps, speeds, intervals, etc.) It doesn't sense anything about the oil at all.

Since this Jeep is new to you, I would go ahead and change it (can't hurt) since you can't be sure if or when the previous owner reset the "counter"

After that, I follow my own scientific process... I change mine anywhere between 3000 miles and when the light says to change it. If I get an afternoon free and I know there is 5000 on this oil change, I just go ahead and do it and reset the counter then.

What is this "oil life" gauge?

I've read that the BMW one is based upon gallons of fuel used. Which, if you think about it, is a pretty good distillation of all the factors.

Maybe I'll get my oil tested when I'm getting close to the next I'll change. I don't really trust the oil life computer. I get it changed at 5k miles. I run my cars pretty hard.

Keith Tanner wrote: I've read that the BMW one is based upon gallons of fuel used. Which, if you think about it, is a pretty good distillation of all the factors.

but how do they handle the loss of oil ? leak ? burn ? …. since no dip stick

clutchsmoke wrote: Maybe I'll get my oil tested when I'm getting close to the next I'll change. I don't really trust the oil life computer. I get it changed at 5k miles. I run my cars pretty hard.

GM recommends 5k for my '14 Sonic … I'll let them do the first 2 - 3 since they're free … then I'll start with the Amsoil

I trust the one in my Z28, but for some reason, I never trusted the one in my CTS-V. It was probably the exact same algorithm, but the Caddy just seemed to go an absurdly long time between oil changes.

wbjones wrote:

Keith Tanner wrote: I've read that the BMW one is based upon gallons of fuel used. Which, if you think about it, is a pretty good distillation of all the factors.

but how do they handle the loss of oil ? leak ? burn ? …. since no dip stick

There's a dip stick in MY BMW. It has an oil level sensor as well, I imagine pretty much everything does these days.

I would not trust anything without an analysis as backup. Myself I am not comfy with extended change intervals, if you read the service manual you will probably find you fall into the "heavy use" or "extreme duty category" in which extended service is not recommended. Dino oil is cheap, I just change it. I probably don't even follow my own advice as I service my own junk when it is obviously ready. At least twice a year I hope.

Keith Tanner wrote:

wbjones wrote:

Keith Tanner wrote: I've read that the BMW one is based upon gallons of fuel used. Which, if you think about it, is a pretty good distillation of all the factors.

but how do they handle the loss of oil ? leak ? burn ? …. since no dip stick

There's a dip stick in MY BMW. It has an oil level sensor as well, I imagine pretty much everything does these days.

ok .. but more and more cars are going to a oil level sensor … and we've seen how unreliable the oil pressure sensors are … who want's to bet that the oil level sensor is any better ?

http://jalopnik.com/5522543/why-the-dipstick-is-dying

Oil lever sensor may not be perfect, but it's a hell of a lot better than your run of the mill owner. Most people NEVER check their oil. They get it changed, but they don't check it between changes.

I'm glad this topic came up. The company Exploder I look after is 6,000 miles past the lube shop suggested interval and the oil change light still hasn't come on. I was beginnning to worry.

As a former Chrysler Engineer I trust the work put into the oil life sensors. They weren't gimmicks. A lit of work was put into testing the validity with a generous safety factor. Imagine the lawsuit costs if we got it wrong and engine blew up.

Trust them, we won't always need 3month/3000 miles maybe one day there will only be annual oil changes. We Engineers do improve things over the years.

Submit to the computers!

I've been trusting the one in the truck for the last 5 years. With our driving style, it's about 8-9k miles between oil changes. I use synthetic oil and good filters and check it regularly.

I'm fine with an oil life monitor as long as the oil in the engine meets the standards the engineers specified.

The biggest problem with extended drain isn't whether the oil still lubricates, its whether there is any left in the sump. Pretty mild consumption can mean a pretty empty pan after 10k.

Advan046 wrote: As a former Chrysler Engineer I trust the work put into the oil life sensors. They weren't gimmicks. A lit of work was put into testing the validity with a generous safety factor. Imagine the lawsuit costs if we got it wrong and engine blew up. Trust them, we won't always need 3month/3000 miles maybe one day there will only be annual oil changes. We Engineers do improve things over the years. Submit to the computers!

Straight from the horse's mouth. Nice.

Thanks. I'll let it ride until it gets down farther. And after looking into all of this, the cartridge style filter is top loaded. I might change my own oil if the Jeep dealer charges more than the Ford dealership did ($22).

The one in my Civic goes at about 8000 miles. It's all highway and I use synthetic, so I'd like to go longer. However it's a CVT and there are lots of hills, so it spends a ton of time at 4000+RPM. So I follow it. The Impala used dino, and would go 12-15k miles. I didn't follow that one. Changed at 7-8k.

Hyundai still tells you to change the oil every 3600 miles. I was surprised when my coworker was always taking hers in, so I looked it up. If you're in Canada, you're automatically on the severe service schedule.