DIY Oil Condition Tester
 

I have a few cars and as such they mostly do low annual milages. Mail away testing always seemed like a pain, but I chanced across this:

Buy Digital Motor & Engine Oil Tester Online ? Lubricheck

Reviews on Amazon:

Robot Check

Thoughts?

EDIT: After going through the Amazon reviews I decided to give it a go for myself, we'll see in a weeks time.

The folks on the Cummins forum had an informative discussion of this device.

Lubricheck - Page 3 - Dodge Cummins Diesel Forum

Nothing conclusive, but interesting. They also refer to another thread or article that was critical of the technology used to determine oil fitness.

And here's one on GM's oil sensor, from Delphi Mexico. You can preview the first few pages for free, where they explain what the sensor's doing. No reason this thing can't do the same.
“Smart sensing” of Oil Degradation and Oil Level Measurements in Gasoline Engines

Frank

Does it test acidity or electrical resistance? Better than nothing i suppose but definitely not conclusive.

I would guess conductivity. They said it gives false positives on oils with too much zinc or other high pressure wear additives.

If anybody knows how they work exactly that would be worthwhile. I'm thinking my Fluke multimeter could do the same test.

Guess I better go look at that GM paper.

Yup, the GM sensor works with conductivity and indirectly measures pH. And they claim you have to measure the conductivity with AC, not DC.

Sounds crazy, but i just change the oil every 5k miles... personally. Smell test is a good indicator of fuel dilution and if you have an air/oil separator you will know how much moisture you have coming out of the oil.

There is no good remote instrument that actively measures pH.
Conductivity is typically measured with AC. Any current induced onto the wires will throw the reading way off. I think hand held conductivity meters use DC.

My problem is the cars in question do 2k or less a year. In the case of my Fiat's fancy required oil it's also around $100 a bottle of oil and filter.

Any idea if a pool tester kit would suffice? What would be the healthy PH range of motor oil?