2006 Trailblazer 6 cyl.

[ekpolk]

I'm with 427 on this one. If you do some research on the GM OLM, you'll note that GM calibrates the system's performance to each engine and vehicle combination in which it's installed. And it's calibrated conservatively. From the info I've seen here, it would appear, at least to me, that oil is somewhere between 50-75% "used up" when the OLM says it's done. Also remember that GM assumes that the owner will be using the least expensive, "baseline" quality API spec dino. We don't have a whole lot of Atlas family used oil analysis here, but the few that do appear do not suggest any tendency by this engine to destroy oil faster than any other normal engine.

One or more of you needs to run out to the OLM's condemnation point and do a used oil analysis.

 

[JTK]

I just recently did an OC on my 2005 trailblazer 4.2L and reset the OLM (dash light). I'll see how long it takes to go on & post back. It's going to be awhile since we use it less than 1000mi/month. I'll probably chicken out and do an OC no greater than 5K anyway, but I wont reset the light until it illuminates. 427 and Ekpolk, do you guys go beyond 6-7K on ~$2/qt 5w30?

Joel

 

[blue_goose]

Naw.... Ekpolk uses that fancy 5 dollar a quart green stuff

Just messing with you sir

In all seriousness I have to see if our 2004 Vue has that Oil Life Monitor..I don't recall seeing it at all with the Honda powerplant...


Goose

 

[ekpolk]

JTK:

It's easy to just say it, but sure, if I had the right set of circumstances and engine, I'd go there, verified of course, with a used oil analysis or two. Actually, I would (actually, I do) use occasional used oil analysis to ensure the safety of ANY oil use plan that I try. As to the 4.2L, I think this engine may actually be a good bit easier on oil than you suspect. But only used oil analysis will tell for sure. The OLM has proven quite conservative in its calibrations, and I doubt that the 4.2L is an exception. Of course, the ultimate guide is your conscience.

BG:

Cool, but correct -- sort of. I got most of my still-large stash of green on some sort of Autozone sale or another. I haven't bothered to make a precise calculation, but I'd say my average price is more in the low $4 range. Hairsplitting for sure, but hey, the stuff sure does hold up well for the longer duration OCI.

 

[frostypanic]

Hey Blue Goose,

Your Satty does have an OLM light. My mom drives a 05 VUE AWD w/ the Honda Motor. Hers goes off between 5k and 6K running Havoline 5w-20. I run M1 in both of my L saturns w/the eco-tec. I use the OLM on both, the 00 goes off at 3K-4K running Max Life and the 03 goes off at 7.5K-8K running the M1. Check out http://www.saturnfans.com for some good Saturn info.

Brian

Actually my Dad just got the fourth Saturn in the family a 07 Sky, sweet little ride.

 

[427Z06]

quote:

---

Originally posted by JTK:
427 and Ekpolk, do you guys go beyond 6-7K on ~$2/qt 5w30?

---

I would have no qualms about doing it if the manual spec'd it and the vehicle is equipped with a credible OLM.

See, here's the beauty of the OLM.

Scenario: You'd like to run the dino that's spec'd, but, your schedule may not allow prompt changes, or, you want to run it right to the end of the recommended interval. But to decide the right interval, you have to decide whether you fall under regular service or severe service. But to do that accurately, you'd have to log all your trips for trip length, oil temps, etc. (Humans are notoriously bad at remembering this stuff accurately). So, since all that's too much of a hassle, you either change early and often, or, you use expensive synthetics to cover yourself. But with the OLM, your covered, so you can run the dino that was spec'd and not worry about it.

I'd still run a yearly UOA just to check on things, since the OLM won't detect a coolant leak.

 

[TooSlick]

Forget the OLM and use my oil change interval formula instead:

OCI = (C*)(ave mpg)(sump/qts)(cubic inches/Hp)

For Mobil 1, I'd use a C* of 80, so you get:

OCI = (80)(20)(7)(255/280)
OCI = (2)(20)(7)(255/7)
OCI = (2)(20)(255)
OCI = (40)(255)
OCI = 10,200 miles

OCI is approx 10k miles or 1 year, even if you factor in low fuel efficiency due to short trip driving conditions.

TS

 

[427Z06]

quote:

---

Originally posted by TooSlick:
Forget the OLM and use my oil change interval formula instead

---

Never did like that formula. You mix independent and dependent variables on the same side of the equation. Something like this would make more sense to me.

OCI = (Sump size x actual mpg x Q)/(A x Cd)

where Cd is the drag coefficient, A is area
Q is oil quality Q=500 for SM/GF-4 dino

But all this is moot point. No way any simple formula like these can come any where near the sophistication of the calculations done by the OLM which takes in account oil temps, trip lengths, engine revolutions, etc, for a particular engine design.

[ July 29, 2006, 09:46 AM: Message edited by: 427Z06 ]

 

[Texas Aggie]

I never posted this UOA, but it was from my wife's 2003 Trailblazer with the I-6. We've been very pleased with it so far!

 

[427Z06]

Thanks Texas Aggie. Did you notice when the OLM alerted for an oil change?

 

[JTK]

Yes, Thanks Texas Aggie! Wow, only 4648mi in one year? I wouldn't expect M1 to look horrible with that use, but it appears you could go way longer based on those numbers. Thanks again for the data.

G/luck
Joel

 

[Texas Aggie]

Yeah, I used to have a company car, so this was babied. I used FP, but not LC. I'm now using LC, on Terry's reccomendation. The filter was a Mobil 1. The OLM always seems to go off at about 7000, but I haven't used it, because at first I was changing it more for break-in, and on this run I hit a year before it hit 7000. I wouldn't be concerned about going longer than that with Mobil 1 and LC. I've really liked this combination.

 

[JohnBrowning]

427Z06, We are being a bit terse!!!I would never push someone to depend on the GM OLM. I think it is much better to use a fixed shorter interval then what might happen with the OLM. Their is no way I would ever feel peachy about leaveing an oil in for up to a year or 17,000 miles with a conventional oil. I spoke with the lady that was in charge of that program at GM on several occasions and had acess to all the algorythms through her. I think that it is fool hardy to put someone else in charge of decideing when your oil is bad. I tend to have higher standards then GM does on when to condem an oil as not fit for continued service.

My wifes Buick has the OLM system and I never use it. It never comes on. It does not matter if the oil has been in the sump for 9 months it has never come on. So I do an oil change every 6 months with conventional oil and call it good.That engine was preety dirty when I bought the car from my Grandmothers estate. It was ran on a diet of M110W30. I am guessing that the OLM was followed when she owned it.

I will also say that most not all of the cars I have seen that used the OLM symstem seemed dirty when they had lots of miles on them! I mean lots of deposits inside the engine, rusty dip sticks, etc......

Imagine how dirty this engine(Texas Agie) would get if instead of Mobil 1 in the crank case for 1 year and just under 5000 miles he had used Supertech Conventional 5W30? Now do that over and over again for 5 years and imagine how the inside of that engine will look? This is why I do not like the OLM. 1 year with a cheap conventional 5W30 is too long for long engine life. By long engine life I mean 10-15 years with no mechanical or seal issues. WHat every OCI you have it should allow the engine to reach 300,000 miles with no mechanical issues at all and very few if any deposit issues. THe OLM system is a system to reduce initial and long term cost of ownership up to the duration of the factory warranty. It is not by any means the best possable OCI to use for ultimate engine durability.

I will say that it is an ingensious system. I would feel better though if they were more conservative or specified a synthetic oil specificly designed for long drain intervals!

 

[blue_goose]

quote:

---

Originally posted by frostypanic:
Hey Blue Goose,

Your Satty does have an OLM light. My mom drives a 05 VUE AWD w/ the Honda Motor. Hers goes off between 5k and 6K running Havoline 5w-20. I run M1 in both of my L saturns w/the eco-tec. I use the OLM on both, the 00 goes off at 3K-4K running Max Life and the 03 goes off at 7.5K-8K running the M1. Check out http://www.saturnfans.com for some good Saturn info.

Brian

Actually my Dad just got the fourth Saturn in the family a 07 Sky, sweet little ride.

---

Frosty-

I was under the impression that the light that comes on does so every 5000 miles just to remind you to change the oil. It is something that can be reset by pumping the gas three times, swinging a dead cat above your head....well ok I made that up but anyways it can be reset until 5k later

I'll look in the manual when she gets home tonight just to sure

My Matrix has a "Maintenance Required" idiot lamp that starts to flash at 4500 miles for about 10 seconds when you start the engine but will eventually stay on when you hit 5K

Goose

 

[blue_goose]

PS I used to hit that site quite a bit when I had an 04 Vue...let's just say my Vue was not built on the same day as my wifes...her's is fine, mine was a disaster

Goose

 

[427Z06]

quote:

---

Originally posted by TooSlick:
The idea of the OCI formula was to come up with something that doesn't require an advanced engineering degree to use.

---

Doesn't matter how easy it is to use if it's an inaccurate formula.

quote:

---

Originally posted by TooSlick:
The idea of using drag coefficient and frontal area is not practical...

---

Why is that, the values are available if one makes an attempt to look them up. And one can also estimate from a similar sized and shape vehicle.

5.10 - 1999 Honda Insight
5.95 - 1990 Mazda RX7
6.27 - 1992 Chevrolet Corvette
7.02 - 1992 BMW 325I
7.57 - 1992 Toyota Camry
8.71 - 1991 Buick LeSabre Limited
10.7 - 1992 Chevy Blazer
11.7 - 1993 Jeep Grand Cherokee
26.3 - 2003 Hummer H2

Took me all of 30 seconds to find those.

quote:

---

Originally posted by TooSlick:
...and those variables (along with vehicle weight) are indirectly captured by including real life fuel efficiency in my equation.

---

That's the problem with your equation. MPG may capture engine efficiency, gearing, power used, vehicle weight, etc, but it fails to capture the one other load variable that is essential. The CID/HP term is essentially useless since it'll hover around one and adds little.

In any event, both formulas will, for the most part, be inaccurate. You'd be way ahead of either of these formulas with a simple hour meter under normal driving conditions.

quote:

---

Originally posted by TooSlick:
For vehicles without OLM's, the OCI formula is a good first cut at estimating a reasonable service interval. That's all it was intended to be.

---

I think you have that backwards. The first rough cut is listed in the manual. If the manual refers you to the OLM, then maybe you need a rough cut. But even in that case, you could use a percentage of the OLM, i.e., change at 85% if you don't feel comfortable going the whole way. If it's an idiot light, run one interval out to the light comes on, do a used oil analysis, and decide from there. One interval run out the full length isn't going to harm the engine.

Funny how Amsoil has no qualms about telling people they can run their oil out to 25K, but if someone runs dino out to 7K, the sky is falling.

 

[TooSlick]

The key problem with the OLM is that it fails to take into account the quality of the oil you're using. It's calibrated for an average quality, API/SM, petroleum based oil, but it provides little insight if you decide to deviate from that type of lubricant.

The frontal area and coefficient of drag idea is interesting, but I'm not sure it would correlate that well with UOA data in real life.

TS

 

[427Z06]

quote:

---

Originally posted by JohnBrowning:
427Z06, We are being a bit terse!!!

---

Truth sometimes hurts, doesn't it JB.

quote:

---

Originally posted by JohnBrowning:
I would never push someone to depend on the GM OLM. I think it is much better to use a fixed shorter interval then what might happen with the OLM.

---

You use the exact same interval no matter the weather, trip length, sump size, driving style, etc? Sounds like you're a 3K/3 Jiffy Lube man.

quote:

---

Originally posted by JohnBrowning:
Their is no way I would ever feel peachy about leaveing an oil in for up to a year or 17,000 miles with a conventional oil.

---

And how many verifiable cases of these have we seen?

quote:

---

Originally posted by JohnBrowning:
I spoke with the lady that was in charge of that program at GM on several occasions and had acess to all the algorythms through her. I think that it is fool hardy to put someone else in charge of decideing when your oil is bad. I tend to have higher standards then GM does on when to condem an oil as not fit for continued service.

---

Yep...a PhD to develop algorithms, many 1,000 of hours of dyno data, enough laboratory equipment to make a $20 used oil analysis look like a note from your Mom on why you missed school, and I'll throw all that away and believe what some yahoo on the internet tells me to do. Sounds reasonable to me.

quote:

---

Originally posted by JohnBrowning:
My wifes Buick has the OLM system and I never use it. It never comes on. It does not matter if the oil has been in the sump for 9 months it has never come on. So I do an oil change every 6 months with conventional oil and call it good.That engine was preety dirty when I bought the car from my Grandmothers estate. It was ran on a diet of M110W30. I am guessing that the OLM was followed when she owned it.

I will also say that most not all of the cars I have seen that used the OLM symstem seemed dirty when they had lots of miles on them! I mean lots of deposits inside the engine, rusty dip sticks, etc......

Imagine how dirty this engine(Texas Agie) would get if instead of Mobil 1 in the crank case for 1 year and just under 5000 miles he had used Supertech Conventional 5W30? Now do that over and over again for 5 years and imagine how the inside of that engine will look? This is why I do not like the OLM. 1 year with a cheap conventional 5W30 is too long for long engine life. By long engine life I mean 10-15 years with no mechanical or seal issues. WHat every OCI you have it should allow the engine to reach 300,000 miles with no mechanical issues at all and very few if any deposit issues. THe OLM system is a system to reduce initial and long term cost of ownership up to the duration of the factory warranty. It is not by any means the best possable OCI to use for ultimate engine durability.

I will say that it is an ingensious system. I would feel better though if they were more conservative or specified a synthetic oil specificly designed for long drain intervals!

---

I'll be short here since you get too touchy feely without providing any verifiable evidence for any critical analysis.

I've seen plenty of engines go well over 200K miles with nothing more than 7500 OCIs on conventionals and they were still running fine. Granted, most of them are well built Honda/Toyota engines, but were talking about a 7 qt sump Atlas here. Now a OLM tells the owner to do a similar OCI, only predicts the OCI more accurately and all of a sudden it's heresy.

Although I will somewhat agree on one point. I'd rather see someone use a quality synthetic and follow the OLM, than use a conventional and change on a short fixed interval.

 

[427Z06]

quote:

---

Originally posted by TooSlick:
The key problem with the OLM is that it fails to take into account the quality of the oil you're using. It's calibrated for an average quality, API/SM, petroleum based oil, but it provides little insight if you decide to deviate from that type of lubricant.

---

Which is a logical choice if you're trying to simplify things for the owner. Otherwise you'd have to give them some kind of switch. For good, better and best oil...and who is going to decide that? You going to tell the owner to believe the marketing drivel on how to set the switch?

quote:

---

Originally posted by TooSlick:
The frontal area and coefficient of drag idea is interesting, but I'm not sure it would correlate that well with UOA data in real life.

---

Thats the problem with any equation that missing essential input variables. I don't believe for a pico-second that yours is any more accurate.

 

[TooSlick]

427ZO6,

The idea of the OCI formula was to come up with something that doesn't require an advanced engineering degree to use. The idea of using drag coefficient and frontal area is not practical and those variables (along with vehicle weight) are indirectly captured by including real life fuel efficiency in my equation.

For vehicles without OLM's, the OCI formula is a good first cut at estimating a reasonable service interval. That's all it was intended to be.

TS