GM Calls 3000-Mile Oil Change a "Myth"

[Gary Allan]

Most of you base your belief based on "acceptable wear" ...acceptable to you. You don't base it on a rational of "acceptable service life". It would be impractical to be running WWII era trucks and cars even if they had been maintained with ZERO wear.

Using a OML would probably NOT decrease the value nor the "serviceability" of a car to any degree that the added maintenance of 3k/3m costs over 10 or 15 years of ownership. That is, until the thing has more value as scrap then it does retail.

 

[Bror Jace]

I'm with Dominic and the others ... it's a glorified idiot light.

I wonder if the GM OLM algorithym in Grand Ams takes into account the glycol from the intake manifold gasket leak most of those cars will develop?

--- Bror Jace

 

[novadude]

quote:

---

I wonder if the GM OLM algorithym in Grand Ams takes into account the glycol from the intake manifold gasket leak most of those cars will develop?

---

The OCI indicator on our Grand Am goes 6k or more before tripping the light. I have deemed it worthless.

... and STOP mentioning those **** gaskets... I keep trying to forget that this is a problem, since our '99 has 70k miles on the original gaskets, and I am NOT looking forward to replaceing them.

 

[brad_d]

I have never owned a vehicle with an oil life monitor, so I don't really have much personal stake in this. However:

Many here are tossing these things off as "glorified idiot lights." Well, perhaps they are. If so, ANY mileage/time algorithm is nothing more than an UNglorified idiot light (without the light, even). Are you folks arguing that that this "idiot non-light" is somehow better?

jthorner's point was very well made, yet it seems to have been ignored. I'd love to hear someone really respond to it.

 

[jthorner]

quote:

---

Novadude said: The OCI indicator on our Grand Am goes 6k or more before tripping the light. I have deemed it worthless.

---

OK Novadude, what is the basis for your deeming the indicator worthless? Is it anything more than old wives tales, or do you have data to back up your gut instincts?

John

 

[Robert R. Wilson]

If all one wants go by is hours of run time, the odometer has an hours readout. With the engine off press and hold for several seconds the trip reset button and the hours will appear.

bw

 

[Lubricious]

quote:

---

Originally posted by MikeW:
One of the reasons the 3 month / 3K mile OCI sounds like a myth to me is that, outside of those that have a direct financial stake in keeping it alive NO ONE authoritiative seems to support it.

It's gotten drilled into the heads of drivers over the years, so it stays alive. There have been too may authoritative sources that say its stupid. Whenever someone does any kind of real test on the subject, it shows that oil, even basic dino, can go much longer than 3K. The one that comes immediately to mind is the Consumer Reports NYC taxi test. The cars showed no increased wear on dino out to 6000 mile OCIs vs 3000. And that was just one consumer oriented test.

Does anyone have anything from source that is in a position to REALLY know, that does not have a direct financial stake, that supports blanket 3K oil changes. I haven't seen it.

There isn't even an argument here. It's long dead.

---

That Consumer Reports NYC Taxi Test is very much disputed, but not until it fooled many people into trusting it.

 

[gudmund]

have been changing oil with a hour meter for over 15 years now and will keep doing it. average 42mph and had been changing it every 200hrs-8200/8400miles. 96metro with 240+thou on it and still not using oil(dino re-refined half of it's life than new dino) now it's a 98 suzuki swift changing it every 250hrs or 10000miles(filter every 5000) with mobil1. 42mph average along with 42mpg average and still complaining about the price of gas!!!!

 

[Audi Junkie]

quote:

---

100 hours of on time accumulated 15 minutes at a time in sub-zero temperatures is not anything like 100 hours of on time accumulated four hours at a time in mild weather

---

Over time, the long runs and short runs should even out, as far as millions of vehicles go. I personally think it is great to have a computer keeping track of all parameters affecting engine oil and reporting an estimate of service due, even if it is in the form of an idiot light. I wish I had a "monitor" but the way I'd use it is to fill with top-quality oil and change it as soon as the oil life indicator came on. I am satisfied with my 6 month oci, safe and effective, economical as well.

 

[Baveux]

jthorner , first I would like to say that I was a firm believer in the OLM. That system have everything to make it a real good tool. Its plainly logic, but....

I changed the oil in December. I put dino 5w30.95% of the milleage is Highway, no stop and go traffic,

We had a not to harsh winter but some very cold morning.The car was plugged a few hours before going to work.

There is no way to say on a Century how much % is left before the OLM goes off.

I was starting to get suspicious at around 9000 klm (5500 miles) I decided to take a Valium

and to wait a little more.At close to 11000 km around 7000 miles I decided to dump the oil and to send it for an oil analysis.

The result is not catastrophic but the 5w30 became a 5w20 and the lead was getting high too.

i haven't reset the olm and I'm waiting to see how long I would have run a 5w20 in my engine.

For the Montana you have to look at the analysis done in November. I followed the OLM,and I end up with the TBN at 1.07, thoil was close to turn to a W20.

So the system is very close to the truth sometime ( Montana) and way off some other time ( Century) So the oil beeing so cheap I decided to go with 5000 miles with the commuter (century) and 3000miles with the grocery getter.I'll let you know when the system will go off in the Century

[ April 02, 2004, 11:37 PM: Message edited by: Baveux ]

 

[jthorner]

Baveux: I've looked at your UOA postings and am missing something. What did the OLM indicator say in each case? Did you change the oil?

I would like to understand your data, but I have not been able to. Your help in doing so would be appreciated.

Thanks,
John

 

[Dominic]

It's just another idiot light

 

[MikeW]

Disputed by who? Jiffy Lube? The ran the cars tore down the engines, and miced the critical parts. They saw no difference in wear between cars that went with 3K and 6K OCIs.

quote:

---

Originally posted by Lubricious:

quote:

---

Originally posted by MikeW:
One of the reasons the 3 month / 3K mile OCI sounds like a myth to me is that, outside of those that have a direct financial stake in keeping it alive NO ONE authoritiative seems to support it.

It's gotten drilled into the heads of drivers over the years, so it stays alive. There have been too may authoritative sources that say its stupid. Whenever someone does any kind of real test on the subject, it shows that oil, even basic dino, can go much longer than 3K. The one that comes immediately to mind is the Consumer Reports NYC taxi test. The cars showed no increased wear on dino out to 6000 mile OCIs vs 3000. And that was just one consumer oriented test.

Does anyone have anything from source that is in a position to REALLY know, that does not have a direct financial stake, that supports blanket 3K oil changes. I haven't seen it.

There isn't even an argument here. It's long dead.

---

That Consumer Reports NYC Taxi Test is very much disputed, but not until it fooled many people into trusting it.

---

 

[Thomas Pyrek]

quote:

---

Originally posted by Lubricious:

---

That Consumer Reports NYC Taxi Test is very much disputed, but not until it fooled many people into trusting it. [/QUOTE]


Consumer reports seems to have a knack of tricking uneducated people into some silly things. I notice it a lot whenever they do something audio.


Just shows, people need to ask "why" alot more.

 

[jthorner]

To the many critics of the CR taxi test all I have to say is:

Do and publish a better one!

John

 

[ekpolk]

The whole OLM thing is really pretty sad. Not because it's allegedly a gimmick, which can be debated (just read above...), but because other systems that really DO monitor oil condition, not just add up factors in a computer, are available. Undoubtedly, the GM OLM is the cheapest available system. I used to fly in the Marines, and many of our engines and helicopter transmissions, had relatively simple devices known as "chip detectors" installed in them. They look sort of like spark plugs and have two magnetic prongs on the end of them, spaced closely together. The concept is very simple: when there's too much ferrous wear metal, it is attracted to the prongs, accumulates, and when it bridges the gap it completes the circuit. In the cockpit, you get a "chip light". I have a tough time believing that it's impossible to adapt similar technology to cars.

 

[Bror Jace]

Guys, we had at least one thread on the CR taxicab study. If you want to argue/debate it, please do a search and resurrect that thread.

That way, those of use who've already said our piece don't have to re-type it.

--- Bror Jace

 

[TooSlick]

I find my "Oil Change Interval/OCI Formula" works pretty well in predicting drains intervals under various conditions:

OCI = (C*)(ave mpg)(sump in qts)(Cubic Inches/Hp)

Or in the case of diesels .. (Cubic Inches/Torque in ft-lbs)


C* is an emperically derived constant and I'd typically use a C* of 40 for a good quality petroleum oil, a C* of 80 for Mobil 1 and a C* of 120 for an ultra premium, extended drain synthetic.

This formula takes into account the main parameters that determine drain intervals, ie the total # of gallons of fuel burned, the sump size, and the "power density" of the engine. You'll note we are multiplying by the inverse of the power density, which is typically expressed in terms of Hp/Cubic Inch.

 

[davidfarming]

For about $7.00 for oil and $5.00 for a good oil filter, I will always change my oil every 3 months. A car is not going to tell me when to change oil.

 

[novadude]

quote:

---

OK Novadude, what is the basis for your deeming the indicator worthless? Is it anything more than old wives tales, or do you have data to back up your gut instincts?

John

---

I have UOA's showing 5W-30 dino that has sheared to 20wt after ~3500 miles... no OCI light. I also have a ~4700 mile UOA on 10W-30 dino showing significant TBN depletion.. again, no OCI light.

I'm sure you can use the OCI light and go 150k on your engine. My problem is, I want it to run LIKE NEW after 150k.