3K or 5K Oil Change?

[Oemtech]

I have been having Blackstone Labs test my oil in the rig and toad at 5K intervals. I have the std tests run plus TBN (Total Base Number) & TAN (Total Acid Number).

I am using Royal Purple 10w30 Synthetic with a 2 qt filter in the rig (8.1L Chevy). I am using Super Tech High mileage 10w-30 and a Super Tech filter (Champ Labs) in the toad (97 Honda CRV 154K+)

The rig oil has come back with 4.x TBN or 50% of additive package left. But, the TAN has been running 5.1 or the oil fairly Acidic.

The toad has come back with TBN of 2.7 or not much left of the additive package. But, the TAN is 4.6 or staring to get Acidic.

I plan to drop the toad back to 3K and the rig to 4k.

[mfire1339]

Dale, Thanks for the info. I will go to 4,000mi also. I'm using 10w-30 mobile 1.

Mike

[DriVer]

Originally posted by oemtech:
I plan to drop the toad back to 3K and the rig to 4k.

Dale, Thank you for sharing the results of your tests with us. This is substantial information that our members need to know.

Before we cast this recommendation in stone please allow for a 3rd test to be resolved so we can plot a curve against the results.

My strategy is twice a year, regardless of miles. I use an Ashland 10W-30 Synthetic and a NAPA Gold 1060 filter.

Good job Dale!

[Davel]

Dale,

I sent a sample of my Mobil 1 5w30 oil that had 5,000 miles on it two years ago after we came back over the Rockies on I-80. The coach mileage at the time was around 25,000 and I used the 2 qt. filter as well. Wear Check Labs said the oil was OK to put back into service as the additives were still good and the other measures were within range. It made me confident about going 5,000 miles between changes, especially since I had spent so much time in the mountains. My plan is to check it again this summer when we get back home.

Dave

[Oemtech]

The TAN number is the reason I am backing down the mileage on the rig.

The DINO oil in the toad does not seem to hold up as good as the synthetic does... even the High Mileage stuff.