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2006 chevy trailblazer_ls
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Discussion Starter · #1 ·
hi folks, i bought my TB used with about 9k miles on it. Since new I have been doing my oil changes every 7500 with synthetic, usually Mobil 1. When I first got it i looked in the manual for when the recommended oil changes were and read about the OLM.

mine never came on so i just figured that it didn't have one. My S10 said to change every 3k for hard conditions and every 7500 for easy driving so I just figured with the synthetic and the way we drive 7500 should be fine.

my question, do you guys think i have an OLM since my light never came on? my understanding is it is base on your revolutions, basically a counter of some sort. i would think if i had one that it would have come on after about 75k miles. I mean I could see if it was some kind of sensor that checked for your oil quality etc.


Any ideas?
 

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2006 chevy trailblazer_lt
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I'm going to assume that you don't have the DIC, which will show you the % of oil life remaining. Both of my trucks have had the DIC so I'm not familiar with the light you are talking about.

However.

On my I6, I got about 10,000 before the oil needed to be changed according to the OLM. From what I read on this forum, that is typical. So, you would not have seen your oil light come on at 7500 miles (and no, the truck doesn't know whether you put synthetic or dino in it--but you can go equally long with both oils according to what I read).

With respect to the 10k before a change, remember that your motor takes 7 quarts of oil, so it "goes bad" a lot more slowly than the oil in a motor that only has 5 quarts.

If you really want to know how you are doing on your oil, send a sample from your next drain to Blackstone Labs for analysis. They will tell you how much longer you could have run it safely. http://www.blackstone-labs.com/ Write them and ask for a free sample collection kit so you will be ready when it is time for the next change.
 

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2002 olds bravada
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All trailvoys come with the "change oil" light. it illuminates for about 2 seconds when the ignition is turned to the ON position. it may be possible that the bulb is just burned out.
 

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2002 gmc envoy_sle
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I've had my truck now for more than a year and the change oil light has never come on (but does when I turn the key on). I have had three oil changes during that time, which leads me to my own question: can someone reset the light before it comes on? :confused:
 

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2003 chevy trailblazer_ls
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the ones without the DIC have the CHANGE OIL light.
we have no ideal how much % is left on the oil.
But since you said that youre now in the 70,000's... your light should have come on by now.
If you dont change your oil-- maybe the people who change the oil are resetting it for you.
Yes you can reset the oil light (on non DIC vehicles) before it comes on.
But if you change your oil- then make sure the light comes on when you turn the key to the start position.
If you dont see it come on- then its possible your bulb is burned out.

OLM uses a mathematical formula- an algorithm. several variables are used... among them being engine RPM's and engine temps. there are more..

I go anywhere from 10,000 to 11,500 miles on my engine oil using the OLM
 

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2005 chevy trailblazer_ls_ext
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the ones without the DIC have the CHANGE OIL light.
we have no ideal how much % is left on the oil.
Unless you have Onstar and sign up for their monthly report. Every month I get an email from them, telling me what (if anything) is wrong with my vehicle, the percent of oil life left, and at what mileage they estimate my next oil change will be.
 

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2002 chevy trailblazer_ltz
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I go anywhere from 10,000 to 11,500 miles on my engine oil using the OLM
Me too....I actually got 12k on the last change before the OLM went on.

Mobil 1 and Wix filters....gotta love em!:yes:
 

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the ones without the DIC have the CHANGE OIL light.
I have the DIC and have the CHANGE OIL light. Maybe another feature of the 2002s?:undecided
 

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2002 chevy trailblazer_ltz
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I have the DIC and have the CHANGE OIL light. Maybe another feature of the 2002s?:undecided
Maybe...i have both too.:undecided
 

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2009 chevy
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All of the trucks have the oil change light (including the trucks with DICs).

Your light is on now (I'll bet), your just not paying any attention to it.

When you start the truck, as you know, all dash lights come on for a quick test. They go out after a sec or 2. All except (in your case) the oil change light, it's staying on for a couple of additional seconds, to tell you the oil needs to be changed. In your case, it's telling you the light needs to be reset.

It's an orange light, right of centre, picture of an oil can and wrench.
 

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2006 chevy trailblazer_ls
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Discussion Starter · #11 ·
I'm a pretty good gauge hawk. I helped my dad farm when I was younger and that was something he ground into us because tractors don't have bells and whistles (or his didn't).

My light isn't on and when I turn the key to aux before starting the light illuminates so it isn't burned out.

I always figured that the reminder was some kind of algorithm based on crankshaft revolutions. Anyone think it is smart enough to actually analyze the oil and let you know when it is dirty?
 

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2005 chevy trailblazer_ls_ext
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I'm a pretty good gauge hawk. I helped my dad farm when I was younger and that was something he ground into us because tractors don't have bells and whistles (or his didn't).

My light isn't on and when I turn the key to aux before starting the light illuminates so it isn't burned out.

I always figured that the reminder was some kind of algorithm based on crankshaft revolutions. Anyone think it is smart enough to actually analyze the oil and let you know when it is dirty?
It's not really about it being dirty. What happens is, GM did extensive testing to develop this system. They would take 2 identical vehicles, for example - run one towing and one not for X number of miles. Then they would drain the oil and run an UOA on it. Also I believe from what I've heard they would tear the engines down after so many miles and inspect them.
http://www.gm.com/corporate/respons...ntenance/simplified_maintenance_qa_040104.jsp

The UOA tells you how much oil life is left. Some people on this and other forums have taken a sample of their oil and send it to be analyzed to someplace like Blackstone. Guess what - the OLM was RIGHT ON the money!
http://www.bobistheoilguy.com/index.php?option=com_content&view=article&id=50&Itemid=56


Frankly I trust the OLM more than I do the glorified idiot lights disguised as gauges (at least on the I6 engine).

You are partly right about "some kind of algorithm based on crankshaft revolutions" but it takes so much more than just the engine RPMS into consideration. Operating temps, load, start up cycles - just to name a few.

I guarantee you - GM tests are far more accurate than someone pulling out the dipstick, looking at the oil and saying "Gee, it looks dirty must be time to change it." :D
 

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2006 chevy trailblazer_ls
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Discussion Starter · #13 ·
so why doesn't my light come on?
I have done every oil change myself since 9k.
 

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I can't tell you that.

When mine comes on, it stays on about 5 seconds after the engine starts and then goes out. It doesn't stay on all the time. Other than that, I have no idea.
 

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2003 gmc envoy_slt
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so why doesn't my light come on?
I have done every oil change myself since 9k.
You may have to ask the dealer next time you go in for repairs. Or if you have time stop and ask. Sorry if i missed but, are you under warranty? Since you've done all oil changes since 9k, and never reset the OLM, something is amiss.
 

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Discussion Starter · #16 ·
I;ve got about 65k. I bought it from a used car dealer. I bout an extended powertrain warranty for major repairs but didn't get the bumper to bumper extended warranty.

i hope my TB never sees a dealer :) I'll just keep changing it, I might call and ask though just for curiosity.
 
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