GM OLM observations

[Drew99GT]

Now that we've been in this arctic blast for the past few weeks, I've noticed the OLM on our 07 Impala dropping like a rock. With only 500 miles on this fill, it's at 67%! So it may go off well before 3,000 miles. Most trips are moderately short, especially my mom's drive to work and back.

During summer, with q fair amount of highway trips, I changed it at 20% when it had 5,000 miles on it.

Now that I've seen it work with my own eyes, I trust the GM OLM for sure.

 

[Mr Nice]

So around 1500 miles it will read 0% ?

 

[Drew99GT]

Originally Posted By: LT4 Vette
So around 1500 miles it will read 0% ?

It looks like it if thing stay the same. My mom drives about 4 miles to work everyday, and to the grocery store and to run errands several times a week. The shopping center/grocery store is about .5 miles away. Every cold start on this interval has been below 20 degrees, with most being on average 10 degrees.

 

[Drew99GT]

Oh, and there's a fair bit of milky immersion under the oil caps of all our cars.

 

[opus1]

Since my Cobalt has the OLM and uses synthetic oil, I planned on following the OLM rather than my usual 3-month/3000 mile give-or-take routine I use with the rest of my fleet. Good to have some real-world experience.

 

[mstrjon32]

Even through cold winters I've never managed an OLM interval of less than 7,000 miles (to 0%) on my '06 Monte Carlo with the 3900. But, the shortest trips I take are about 12 miles.

Dropping to 67% with only 500 miles is insane!

 

[XS650]

An OLM doesn't always tell you to leave your oil in longer than you used to

1500 miles did sound extreme until you listed the extreme driving conditions and the milky looking goop at your oil fill. Maybe the OLM knows something

 

[SuperDave456]

Im curious as to if you could extend the change intervals if you took her car on a longer afternoon drive.

This would be tough to test and get reliable results.

Then again, with your temps and possible bad weather conditions to go along with the cold, it may be better (safety wise) to just go by the OLM and not worry about burning off all the condensation and blowby with the drive. Afternoon drives on ice are not recommended by anyone I know.

 

[Drew99GT]

It's also had lots of 2 to 3 mile Christmas shopping trips.

It's also had a -8F un-garaged cold start to the grocery store (.5 miles away).

I'm guessing on the 500 miles (didn't exactly write down the mileage at which it was changed), but it's got to be around 500-700 miles I'd say. All short trips in frigid weather. Lots of them! Probably 20 miles of short trips everyday for the past several weeks. No trip planning what-so-ever.

 

[Drew99GT]

Oh, and of course she has to do the obligatory .25 mile drive to lunch or to shop during lunch break!

 

[Cutehumor]

If I had a GM OLM, I would use syn, change out at 0%

 

[Drew99GT]

Being the cheapskate that I am, I couldn't stomach using synthetic out to only 2,000 miles and about 3 months!

I got a huge stash of Valvoline Durablend 5w-30 on sale for this car and plan to follow the OLM, but if it's still at say, 10% left with 7,000 miles, I might start biting my nails and itching to change it!

 

[JTK]

Originally Posted By: Drew99GT
It's also had a -8F un-garaged cold start to the grocery store (.5 miles away)..


I would have guessed it was way colder than that to have the OLM chop so much off? My 2007 Cobalt 2.2L is no where near as aggressive, even with some cold short trips. I've got 7500mi on the oil and it's at 28%

 

[NHHEMI]

By any chance is your Mom letting it sit at idle for extended periods to warm it up before going? That is not going to help the OLM.

I had 2 Silverados( 05 & NBS 07 )with the OLM and I was always anywhere from 35-50% when I changed at 5K even in winter unless I did a lot of warm up idling. Idling caused it to drop fast.

 

[chet2]

cold weather is tough on oil...when oil is warm there is no wear..i think people in cold climates should take out on hiway once a week to burn off condensation...that is interesting sabout the OLM, it seems to be accurate

 

[Drew99GT]

Yea, I think she idle's quiet a bit. When she's shopping with anyone else and they go into the store, she'll sit and idle in the parking lot with the heater blasting.

It doesn't bother me at all. The car is a tool. Plus she has a condition in her hands where if they get cold, the capillaries shut and stop blood flow and her hands turn white. The result of frostbite while skiing back in the stone age (hope she doesn't read that

)

From what I've read here, the 3.5L LZ4 motor tends to get to 0% faster then many other GM models, especially the Ecotecs.

 

[SteveSRT8]

We have extensive fleet experience with the OLM on GMC trucks.

If you use dino it is a little too long, but synth interval is good. Our oldest truck has about 120K miles plus a little under 4000 hours stationary operation. Typical interval for us is around 4k but that is due to stationary work.

Our Silverado used for deliveries only is getting almost 14k!!!

I wouldn't hesitate to trust it. It is really comprehensive.

 

[zulu]

I've noticed the same thing. My Malibu (2.4 Ecotec) usually goes about 90-100 miles per 1% OLM. Now that it's SUPER cold, it is ticking away at almost double that rate. All the Ecotecs have 5 quart sumps, so they seem to go a bit longer on the OLM vs the rest of GM's V6/V8 lineups. My Silverado with the 5.3 only gets about 5500ish at 0%.

 

[Drew99GT]

Originally Posted By: zulu
All the Ecotecs have 5 quart sumps


That's exactly why I think the 3.5L V-6 is calibrated more conservative. It only has a 4 quart sump.

I might check the dipstick and see if it reads higher then full, meaning the oil is loaded with fuel and moisture.

I bet GM calibrates this engine knowing in cold weather that for the size of the engine compared to the Ecotec, the amount of fuel/moisture buildup as a percent of total oil volume is much greater. Makes me wonder why they went with a 4 quart sump on an engine almost twice as big as the Ecotec.

 

[zulu]

Dunno. GM has always had somewhat undersized sumps compared to the rest of the world.

Heck, my Silverado only holds 6 quarts. 1 extra quart over the Ecotec, and more than double the displacement. Go figure...