time between oil changes

[kenmac]

How does this oil life system on the vehicle know when the oil is used up ?(adds in the oil are used up, oil loaded with contaminates etc,) How does this meter know if I use regular oil that's good for 3000 mi vs synthetic that is good for 25000 mi ?

 

[kenmac]

I would love to see a comparision between an oil analysis and the vehicles computer oil life meter though.





I would love to see this info. also. Mabe someone here has compared oil meter vs analysis. Would be good to see how close they are

 

[slowrev]

We also have a responsibility to the planet and that is to get the maximum usage out of our non renewable resources.



Another good reason to go synthetic

One question I have never gotten an answer for is:
How much more efficient on oil useage is synthetic anyway ? How much oil / energy does it take to make 1 QT of synthetic vs one quart of dino oil ?

 

[kenmac]

One question I have never gotten an answer for is:
How much more efficient on oil useage is synthetic anyway ? How much oil / energy does it take to make 1 QT of synthetic vs one quart of dino oil ?

Don't know. I guess you would have to ask the folkes that make both. I have read that they have to do alot (add this take out that )to dino just to get it usable as a motor oil. I would bet that as much dino that is used that the synthetic would come out on top.

 

[DieselPower]

I am always thinking of how to the long-haul over the road truckers manage to change oil at regular mileage intervals.... One trip crosscountry might be 3500 miles. Do they change oils at 3000 miles?

Bob

No. Change intervals on over the road tractor engine go from 10,000 miles and up. With UOA I have seen modern engines in the 13-14 litere range get as much as 100,000 miles on a oil change. The norm is 10K with some people running 15-20K. Those that do analysis get the maximum life out of their oil and maximum protection for their engine.

Don't forget these engines have somewhere between 40 and 68 quart oil capacity's. 40 for most and with a Luberfiner filter system they can have a total of as much as 68 quarts.

To the original poster. If your vehicle has a oil life monitor and you want to stick with dino oil you can safely go by the OLM's change intervals. One thing to remember is that these monitors are based on using a bare minimum API clasified oil. If you use higher quality oils they can go even farther. If you switch to synthetic, the best way to get max oil life is to start using a UOA program. Best for the oil, best for the engine and best for the enviroment.

 

[deerefan]

thanks for the replies....how the oil life system monitors the oil breakdown remains a mystery to me. I'll try the synthetic and see how the monitor reacts. Like a previous poster said, i think it monitors your driving habits and evaluates it to monitor your oil. I guess i'm being a little old fashioned still changing oil at 3k miles on these new vehicles. Who does used oil analysis? i'm in baton rouge if anyone knows of a place here.

 

[DieselPower]

The oil life monitor doesn't actually "test" the oil. It uses a computer program to calculate how you have been driving. It takes into account hard acceleration, speed, temp, amount of fuel used and many other reading's. Crunch's all the numbers and calculates how much life it has taken out of the service life of the oil. The harder you drive the sooner it will tell you to change the oil. Long highway trips under little load and it will calculate much longer drain intervals.

This one is probably the best descriptions about the GM OLM and is from GM. http://www.gmgoodwrench.com/_res/pdf/OLS1.pdf

Description of the system. GM's Oil-Life System Improves Timing of Oil Change

For UOA's there are numerous companies that do it. Just do a google or yahoo search for a list. Here is the company I have been using for years.

WearCheck - Condition Monitoring through Oil Analysis

 

[KICK]

What DP said about Big rigs is true. oil changes and maintnence intervals in fleets can be determined thru oil analysis, keep in mind they use those rigs to make money and changing the oil too early hits their bottom line in downtime and excess costs per mile.

I work in a large municipal bus fleet, that type of service is murder on the oil and engine and we recently implemented a 3000 mile Oil change interval, from a 6000 mile interval that we used for years ,mainly due to the fact that with the addition of EGR to these engines, we were getting so much sludge buildup that we had many premature failures of our engines due to lubrication problems.

so the length of time between changes is really determined more by type of service, fuel used, hours etc... than an arbitrary number like miles.

city bus averages maybe 8 miles in an hour, has about 50% idle time with a bunch of full throttle accelerations in between while a over the road truck may average 50 or more miles per hour at a nice steady speed. a bus would run more hours to go 3000 miles than that OTR truck will run to go 15000.

thats why picking a mileage isn't really the best way to do it.

I have a 93 GMC pickup that I bought new and it has 245,000 miles on it.
I used Mobil1 the whole time I've owned that truck and changed the oil and filter at a 10k mile interval. I picked that number of miles between changes because I thought it was reasonable and easily remembered. I know the oil would last longer if I wanted to go thu the hassle of doing oil analysis but I just never thought it was worth it for myself. If I ran a fleet I would definitely do it the more technical way.

I guess the whole thing comes down to what your comfortable with, but you should be able to go more than 3 k between changes using dino oil and way more than 5k using synthetic.

 

[cp1969]

I am always thinking of how to the long-haul over the road truckers manage to change oil at regular mileage intervals.... One trip crosscountry might be 3500 miles. Do they change oils at 3000 miles?

More like 15,000 to 30,000 depending on type of operation. Local hauling with PTO time, 15K. Long haul, 30K not unusual, with bypass filter, even with dino oil. Few fleets run synthetic--seems like Rotella and Chevron have most of the market.

3,000 mile oil changes are only being touted by those doing the changes. Twice a year regardless of miles is all I give 'em now.

 

[kenmac]

Like I said, the cat dealer in my area that does my uao's ,say that these rigs come in all the time to have their oil tested just to see if they can go another 100 miles or so. I guess 100 more miles = to $ 's so they want to get the max out of their oil without damage to their engine. D.P. if I were to use a group 4 synthetic in an engine that has an olm. that engine doesn't the difference in oil (yn or dino )so, It could say change the oil at 3000 mi even though the oil is good for 15000 mi. would this be correct ? I'am asking cause I don't own a vehicle with an olm & haven't read up on these systems.