I go by the DIC, I got 11,000 miles form the original oil, and it was still at 3%
I had 2 Pontiac Montana's before the HHR and I always went by the DIC,
and they both reached 90,000+ miles before I traded them in, and absolutely no engine problems.:twothumbs

 

My DIC read out is 61% right now. It has approx 4600 miles on the oil, and 37,4xx miles on the engine.
I will change it when it gets down to 30% or so, roughly 7000-7500 miles.

I am going full syntetic at that point, and changing the filter at every 5k, and leave the oil for 10k miles.

I drive alot...I figure 30k/year...so 3 oil changes, and 6 filters cant hurt anything.

My last car used a "message center" much like the DIC, and it measured oil life % by key strokes vs miles driven. I could go about 1% oil use per day, at 110-130 miles a day driven 50-60 miles per "key stroke".

 

I'll second better oil technology and better engine tolerances and design.

Changing the oil every 3k is the "old school" way of thinking. Dino oil is good for at least 5k.

Case in point is my wife's 2001 Grand Prix with the 3.4 V6. I have been changing the oil with full-synthetic and a high grade filter (k&n, Mobil1) initially 10k miles then every 12-14k miles. I may have gone 15k a time or two. I started this synthetic interval around 45-50k miles. Did not change the filter in between changes-maybe I could have. If you saw the vehicle you would agree it looks like it's in great shape. You'd be shocked to learn it has 243,000 miles on the ticker and NO engine problems. Doesn't use oil, does not blow smoke and STILL gets better gas mileage than the 06 HHR.

The HHR...GM has spent a lot of time and research into the design of the OLM. Use it. Our 06 has 26k miles on it and the oil has been changed twice. Getting ready for the third (OLM 35%) and switching to Mobil 1.

Toby

 

I read an interesting article saying the 3k rule is just a money ploy for the "Quick Oil " change places.With the new formulated oils and better engine materials 5 k changes are the minimun.I've experimented on my 89 truck( 5.7) with syn oils and can say they do wonders..that is until the wear factor comes in (RE: valve guides) then you are wasting money by burning it.Ive logged 279k before a broken rocker arm got me and bent a valve.(Heh-Heh, was coming down from a hard run down the hwy)I have never "babied" this truck.It was used for just about everything,including daily 100mph runs down the autobahn for the 2 years I was in Germany, towing the boat and 35oo# race car/trailer for 6years.On tear down ( figured it was time anyways) the bearing surfaces were great!Oddly enough , the rings were gone but never gave any indication other then usage which was about 1 qt per 1k..no daytime smoke (but at nite you could see the cloud in the headlites of the car behind you only when you were getting into it).The pistons "fell' out of the cylinder once the rods were disconnected from the crank!Next to none ridge on the cylinder walls. Power was good and milage was good.For a 5k lb truck, 23 on the hwy was great!longest I went between changes was 26k..then I went about 12k till the guides were wore(about 150k miles,after that i changed heads added a cam,intake and a few other mods)After that I went by the color averaging about 12k. A note here,I was also using a 2 qt filter and kept it changed about every 6k.
I found no sludge build up, just a slight discoloration.Gotta love Mobile one oil!
I've used 0wt30 , 5w30, 10w30 and on occasion 20w50. with out any noticeable differences.I would not recommend using any lite oils if you have any kind of leak or seepage..you will also find leaks you never knew you had.
For the 07 HHR..I'll play it by ear..thinking of Amsoil as I've had great performance from it on my Harley(Gave a 10lb increase in oil press over "stock" oils sitting in traffic on a 90+ deg day).For now at 81% I have time to ponder on it.....

 

We follow the DIC. The dealer wouldn't even change the oil till we were under 15 or 20%. Someone on this forum posted some real good info on how good the computer is at analyzing the oil.

There is also a law going around in congress that some are trying to pass to eliminate 3k oil changes.

 

Heres some metric numbers:
I have an '08 with about 2500km on it. I just got my second monthly diagnostics email from Onstar. It let me know I have 75% left for the oil life, next projected oil change at 10,200km. Sounds great, but the service guys will miss me.
Oh, and it tells me my tire pressure is low, 172kpa right, 180kpa left, recommended is 204kpa. Now how the heck do I convert that to psi?

 

My last two oil changes I had schedualed at a DIC reading 0f 5%. My reason for that is I was doing a lot of traveling, so I did not want to take a chance of going over the limit. I have also kept on useing the Mobile 1 syn. in it. And the service manager at the Chevy dealer I take it to even said to follow the DIC.

 

some bad habbits are just hard to break, but i've been following the OLM too and really haven't had anything bad happen. im getting there slowly but surely....done my last two oil changes at about 5000 a piece.

 

I've always changed oil on all my vehicles every 3000 miles...

I guess I've been forking over too much $$$ to the petroleum manufacturers all these years.

 

I'm done with the constant oil changes. M next oil change will be Amsoils premium oil, rated for up to 17k miles with severe duty. I'll change the filter every 5k and test at 10k to see what the wear is like.