pf59 filter doing wrong

[pastor scott.com]

heard that if you switch to pf59 from pf44 it will throw off oil monitor system. whats the real deal ?

 

 

scott

[GM-Tech]

heard that if you switch to pf59 from pf44 it will throw off oil monitor system. whats the real deal ?

 

 

The oil life monitor has no clue about the oil filter, the oil, or even if you have oil in the engine. It's simply a number in the PCM that is subtracted from with each engine revolution, with "penalty" subtractions done for cold starts, etc. When the count reaches zero or nearly zero, your change oil light light/message appears.

 

Resetting the change oil message resets that number to it's predetermined value and counts begin subtracting again with the next engine start. I don't know how anyone could say that a filter somehow affects this.

[facn8me]

heard that if you switch to pf59 from pf44 it will throw off oil monitor system. whats the real deal ?

 

 

The oil life monitor has no clue about the oil filter, the oil, or even if you have oil in the engine. It's simply a number in the PCM that is subtracted from with each engine revolution, with "penalty" subtractions done for cold starts, etc. When the count reaches zero or nearly zero, your change oil light light/message appears.

 

Resetting the change oil message resets that number to it's predetermined value and counts begin subtracting again with the next engine start. I don't know how anyone could say that a filter somehow affects this.

 

<{POST_SNAPBACK}>

 

 

 

 

 

Are you saying that nobody took in to consideration how much oil the engine holds and what size oil filter was to be used to figure out the math? So what you are saying is 3 qts of oil and no oil filter would last as long as 6qts and an oil filter? I am the one that said a bigger filter would effect some of the calculations used to determine oil life. Although a bigger filter would err on the side of caution just like removing it all to gether would shorten the life of the oil. Or am just completely lost.

[GM-Tech]

Are you saying that nobody took in to consideration how much oil the engine holds and what size oil filter was to be used to figure out the math?

 

I am sure that the engine's capacity may have some small effect on the baseline number that is plugged into the PCM from which to subtract; however, putting in a filter that holds a few ounces more or less oil and has a slightly larger/smaller filtering surface due to its size is not going to amount to a significant difference in terms of oil life, in my opinion.

 

I would say the biggest factor in oil life is the operating conditions which affect additive depletion and oil contaminants (combustion byproducts, such as moisture) not a filter that's an inch or two longer/shorter. If you're talking a MAJOR difference, such as your 3 qts w/no filter vs. 6 qts w/filter, then yeah, but how many engines do you know that hold only 3 qts. and have no filter? None of ours, that's for sure.

[facn8me]

So we can agree it does effect the calculations in a small way, but not enough to make any difference unless a person removed the oil filter and only ran 3 qts of oil

 

 

I would love to hear an engineers take on this. Of course I'd like to take a few engineers out back and smackem around a bit also

[redvett]

The difference between the low & full marks is more oil than the filter hold. The little more or less oil isnt going to make any difference.

[facn8me]

I am going to have to stop answering questions on here. Just call me silent bob from now on

[rascal]

the oil life monitoring thing, doesn't really check your oil. it uses the standard amount of oil and filter in it calculation. with how many rpm's the motor has turned and the heat the motor produced, and what the temp was at each start (like hot vs cold starts). Is this what I am understanding to be correct? Thats what I'd thought, well never thought about the starting temp part.

[100R1]

GM OLM is different for each engine design.

 

Basically the data base in the computer is different for each engine family.

 

The cadillac enginge that use roller tappets on the valve train can go 12,500 miles under ideal situations before the OLM will come on.

 

Other engines with the standard old fashioned valve lifer configuration creates more friction which shears the oil additives etc. and the OLM will go off much earlier

 

**note: the roller lifter is just one aspect as to why the caddy engine goes to 12,500 OLM there are a bunch of other things that are put into the data base for consideration

[USA1Fan]

That probably helps explain why my Trailblazer went so much farther before the OLM indicated a change needed than my truck or Malibu do. Much higher tech involved in that DOHC i6 than in our trucks, and it also held 7 quarts. (Not complaining about the 'old' pushrod in our trucks though. Nice grunt and excellent gas mileage for the power it gives.)

[GM-Tech]

how many rpm's the motor has turned and the heat the motor produced, and what the temp was at each start (like hot vs cold starts). Is this what I am understanding to be correct?

 

Yes, that's correct. For the sake of argument, lets say that the oil life monitoring system subtracts 1 from the starting oil life number for each 10,000 revolutions of the engine when it's at normal operating temperature. BUT, before it reaches normal operating temperature, it subtracts 10 from the number for each 10,000 revolutions.

 

So, you start your truck and drive straight from New York to California, non-stop. For the first 10 minutes or so, 10 will be subtracted for every 10k revolutions, but for the rest of the trip only 1 will be subtracted for every 10k revs.

 

Now, grandma across the street starts her car up, goes three miles to the grocery store and back. She's going to do this 500 times to get the miles on the odometer you got on your one, non-stop trip to California. For the entire time her engine runs during that 3,000 miles, 10 is being subtracted from the oil life monitor, because the engine barely reaches operating termperature on those short trips to the store. You, however, are only having 1 subtracted the entire 3,000 mile trip.

 

So grandma is going to have her "change oil" light come on after much less mileage than you. You could probably drive back and forth to California two, maybe three times, before your "change oil" light came on whereas she may only go the equivalent of one trip from NY to CA.