lobuxracer

iTrader: (2)

It would take a very low iron content for me to even consider 25k miles as reasonable. Iron tracks mileage, and iron content in the oil is the most important number behind silicates. If you have silicates, you have bad air filtration. If your iron is high, your oil has run a long time and become abrasive. So, if you want to run a 25k mile OCI, you'd better plan on sampling at 10k, 15k, and 20k to check iron content. You'll also want to spend the extra $10 for TBN to see if there is any base left in the oil to neutralize the acidic byproducts of combustion. When TBN goes below 1, you are in the danger zone.

2URGSE

I've tried Castrol Syntec until I saw what the oil looked like during the drain after a short interval.

Switched to RedLine Oil 5W-30, oil lasts much longer and the car runs much smoother. Toyota OEM filters.

My buddy who had a 2008 ISF at the time switched as well and said he noticed a big improvement.

Bulls23337

iTrader: (2)

What oil filter are you using?

LukeRich

oh the ol 3k/3mnth myth. I remember trying to tell people this before the internet and ppl would get upset. But Empirical data always wins in my world.

semnosNSX

How many miles does it take before the oil maintenance light comes on? I think it's around 5k-7k. Anyway, that's how often I change mine using Mobile 1 full synthetic and OEM filter.

-Steve

VDODSON

Every 3K miles is a waste of money.

JT2MA71

iTrader: (7)

I also use Amsoil (signature series) 5W-30. I switched to it when I drained the factory oil at 3500 miles. I went 6000 miles with the Amsoil just because engine is still breaking in. I will then change every 8k from now on which will be about yearly (or longer)
My latest Blackstone analysis is posted on Lance's thread.
I used the same oil on my LS430 and went 12k miles every change.

4TehNguyen

iTrader: (1)

ran 3 vehicles to 10k on synthetic and all wear levels came back normal or even below the average. TBN tests showed around 10k was an optimum interval before the TBN hit 1.0. Changing synthetic at 3k or even 5k is a huge waste of money and time. I exclusively use synthetic in the family fleet now as it literally cuts my oil change labor in half.

vbb

iTrader: (3)

I do approximately every 8K miles... or at least once a year (since my ISF is not my daily, I'm more likely to hit the year mark before the 8K mark these days).

I use Amsoil or Pennzoil Platinum synthetic.

But just listen to Lobux on this one (see the post he put up a few above mine). He's done all the testing and I'm comfortable with his findings and data on this and trust that way more than the old industry standard of "once every 3K miles" that was pushed a lot, especially during the 90s when I started driving. Heck, a lot of cars from the factory are recommending longer and longer intervals. Funny how that has become the new standard, especially now that more and more manufacturers and dealerships are offering free maintenance for a period of time on their newer vehicles.

Sean

iTrader: (3)

I do mine every 7-8 months going by time rather than miles. I don't put a lot of miles on the car since I mainly work from home and have a short commute when on site but my driving is mostly city stop and go traffic. Maybe I could go longer and am overly concerned about my driving conditions decreasing the oil life?

Pennzoil Platinum, also. I've practically gotten it for free my last three oil changes.

4TehNguyen

iTrader: (1)

if you want to be positive, send a sample in for testing. My guess is you will still be good even at 7-8 months