: Engine oil life % - Who uses it?



infin1ty
02-12-05, 02:40 PM
From those who use it, at what % of remaining oil life level do users of this guide change their oil? Also, does anyone have any insight into the algorithm that it uses?

blunted
02-12-05, 03:57 PM
I always go by the oil life reading, it was carefully designed and serves its purpose quite well by taking into effect the different driving conditions you are experiencing. I usually make an appointment to get it changed when it falls under 20%.

JimD
02-12-05, 03:59 PM
I use it for every oil change and sometimes run another 500 - 800 miles (one or two tanks of gas) after it counts down to zero.

BBob will have to list the variables and I plan to capture his response this time!! What I do remember from his posts on the subject is that engine temp. and run time at normal operating temp. is one of the major variables.

danbuc
02-12-05, 05:10 PM
I usually chnage it at around 20-15%, but sometimes I'll run it down to 0% if I have too.

Ranger
02-12-05, 06:13 PM
I change mine after the "Change Oil" message comes on (10%). Bbob has explained the algorithm several times. As well as I can remember, as previously mentioned it takes into account engine temp, outside air temp, run time, rpm, miles and I'm sure, several other things.

SHERIFF
02-12-05, 09:04 PM
I sure hope you guys are right about this oil change monitor. I have been 3,000 miles since the last oil change in the bronze DTS and it still reads 66% of oil life left. :banghead:

dkozloski
02-12-05, 09:56 PM
You can bet that if anything the engine oil life monitor is very conservative.

Ranger
02-12-05, 10:00 PM
I sure hope you guys are right about this oil change monitor. I have been 3,000 miles since the last oil change in the bronze DTS and it still reads 66% of oil life left. :banghead:
Sherrif,
I was a 3K guy til I found Caddyinfo and this forum. Since I do mostly highway driving I reach the cap of 7500 miles, and I am comfortable woth it.

growe3
02-13-05, 04:05 PM
I was skeptical at first, but it seems to work fine. I change at the first convenient time after the oil life monitor pops up. I get about 4,000 – 5,000 miles per oil change.

When I had the engine open to repair the head gaskets (at 125,000 miles) there was no appreciable buildup in any of the oiled areas.

My 93 STS has 168,000 miles on it, with no lifter or other unusual engine noises.

-George

dkozloski
02-13-05, 08:49 PM
In answer to your question of who uses the % of life function. Any Cadillac owner who has intelligence enough to dress themselves.

caddydaddy
02-14-05, 11:08 AM
The people who use it are the ones who don't want to get ripped off by the QuickyLube places that adhere to the 3k miles gimmic! I usually change mine when it gets under 20% which is usually more than 6,000 miles or so by then.

dkozloski
02-14-05, 11:30 AM
Nearly all of the contamination in the oil has to pass the rings to get there. Cadillac has a more than excellent handle on that problem. The PCV system removes the fuel vapors and moisture. What's left behind is black carbon particles, some acids, and miscelaneous combustion by products. Depending on how hard the engine is driven and how hot it gets some amount of the oil is oxidized and/or converted to something else that may or may not be harmful. Synthetic lubricants resist this nicely. As a reference point. I bought a Sears Roebuck lawn mower in 1975. I ran it every summer for nearly thirty years. I never changed the oil and I never had to add any. It's nothing to brag about but what works, works. I took it to the landfill and put it in the area we call the "country store" where you trade your junk for someone elses. As far as I know it's still going. I am the facilities and ground equipment manager for a regional airline. We found that the equipment manages just fine with oil changes every six months, "dino" oil in the summer and synthetic in the winter. Pleated paper air filters contribute more to engine longevity that anything else I know of.

lowscola
02-15-05, 10:37 AM
I use it and start to think about a change when it gets < 25%. I also use mobile 1 which helps me put my mind at ease...

Dooman
02-15-05, 10:49 AM
I change it when it says to.. just to shut up my Wife! Pretty difficult to push that reset button I guess?? "Car needs an oil change.. Car needs an oil change" Geeze.. once a day would be a much nicer reminder..

turbojimmy
02-15-05, 11:22 AM
I bought a Sears Roebuck lawn mower in 1975. I ran it every summer for nearly thirty years. I never changed the oil and I never had to add any. It's nothing to brag about but what works, works.

That's pretty funny. I have a 40-year old Craftsman snow thrower. I've had it for 5 years, my dad owned it before me. The oil drain plugs are rounded off so they won't come out. Neither my dad nor I can remember when the oil was changed last. In the 5 years I've had it, the level has never decreased so I've never added any new oil to it. It's pretty black, but if it ain't broke....

I haven't had the pleasure of driving my Caddy long enough to change the oil. It says 99% right now. I'm going to change it anyway because the filter has probably caught a bunch of mud.

Jim

BeelzeBob
02-15-05, 02:00 PM
From those who use it, at what % of remaining oil life level do users of this guide change their oil? Also, does anyone have any insight into the algorithm that it uses?


You might want to reference the following post http://www.cadillacforums.com/forums/showthread.php?t=16002&highlight=engine+oil+life+monitor as there is a detailed explaination of how the oil life monitor works.

Use the search feature in the forum tool bar above and type "oil life monitor" into the drop down search box and read my additions to the various posts.

JohnnyO
02-15-05, 03:44 PM
I do it every 6 months on mom's car regardless, the OLM is usually around 30%. Dad's car a little less, but it gets driven more.
Mobil 1 in both and I save the leftover to put in the snowblower once a year. :D
Overkill I know, but that's me.

oldgamer
02-15-05, 04:54 PM
...I haven't had the pleasure of driving my Caddy long enough to change the oil. It says 99% right now...

We talk about engine oil, not transmission oil here.



Talking about oil change... and other things...

I noticed that can be in two different categories: some of them change oil religiously after 3K no matter what. They never use regular gas, just a premium. They often use synthetic oil. They change plugs and wires “just in case” right after the car purchase. They go only with Delco batteries. They spent huge deal of money on they cars. I believe they do that because of luck of knowledge. Other category change oil when indicator tells them to do that. Only one variable I believe indicator missing: the time. Indicator can’t say when oil was changed.

turbojimmy
02-15-05, 05:28 PM
We talk about engine oil, not transmission oil here.




The trans says 100%, the engine oil says 99%. I was referring to the oil filter being clogged with mud. The oil was changed after the flood but not the filter.

Jim

BeelzeBob
02-15-05, 11:56 PM
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The oil life indicator takes time into account. Just because it cannot tell when the oil was physically changed does not mean time isn't taken into account. The oil life monitor starts counting down when it is reset...the assumption is that it will be reset when the oil is changed so the time interval will start over when it is reset. There is just no reliable way to automatically reset the oil life indicator when the oil is changed. Open for ideas on how to "tell" the system the drain plug was removed and fresh oil was put into the sump.....LOL.

JohnnyO
02-16-05, 08:25 AM
I was referring to the oil filter being clogged with mud. The oil was changed after the flood but not the filter.
Ooooookay. :jawdrop:

Actually as long as the filter was on tight it should be alright but I'd change it just to be safe. I off-road my truck(s) and the filter catches mud between the lip and the gasket and I've never seen it get past. And I get UOA's too.

turbojimmy
02-16-05, 08:38 AM
Ooooookay. :jawdrop:

Actually as long as the filter was on tight it should be alright but I'd change it just to be safe. I off-road my truck(s) and the filter catches mud between the lip and the gasket and I've never seen it get past. And I get UOA's too.

Maybe not mud, but perhaps silt. Muddy water had to have entered the crankcase through the dipstick tube and whatever breathers there are. If it's the same water that filled the inside of the car, it leaves behind a fine silt when it drains. On the inside of the body panels (like the bumper cover) you can see the water lines like the rings on a cut tree as the water receded.

Water is heavier than oil and would thus sink to the bottom of the pan. Perhaps the silt wouldn't be left behind because everything is coated with oil? I didn't see what came out of the crankcase, but the oil was changed before it was run. Now that it's run a bit (20 miles), the oil still looks okay. I guess in theory all of the water should have drained out with the first oil change so the filter may not be that bad. I'm obviously going to change it anyway. Maybe I'll hack it open and see what it looks like. Or maybe what I don't know won't hurt me....

In any event, I do plan to use the Engine Oil Life % on this car. It's a nice feature so why not use it?

I change the oil in the GN every 3,000 miles but only because that equates to once a year.

Jim

oldgamer
02-16-05, 09:50 AM
The oil life indicator takes time into account. Just because it cannot tell when the oil was physically changed does not mean time isn't taken into account. The oil life monitor starts counting down when it is reset...the assumption is that it will be reset when the oil is changed so the time interval will start over when it is reset. There is just no reliable way to automatically reset the oil life indicator when the oil is changed. Open for ideas on how to "tell" the system the drain plug was removed and fresh oil was put into the sump.....LOL.

When I say oil life indicator doesn't take time into account I meant whole time, not just engine running time. Resseting oil life time allows to indicator start counting from scratch. I didn't say that it should some how sense the phisical oil change. What I try to say is that oil should be change after some time no matter what, let say every 8-12 month. After reset button was pressed, indicator can count actual time. I don't remember for sure, I guess the manual says that despite oil indicator shows oil should be changed after certain time. That's why I belive oil indicator takes into account only actual engine running time, not all time. In reality much more often oil changed because of milege, not because it's just too old. In my case, I drive car mostly on weekends and making barely couple thousands miles per year.