Evidently, in California, 30W motor non-detergent oil must have special labeling that says that this oil should not be used in newer motors.

Rather than add the above verbiage to the labels, manufacturers have decided to market this oil as air compressor oil (for example, Napa's part number 82-6020). The words '30W non-detergent' does not appear on the label.

FYI. Dean

Just about any non-detergent oil has a warning on the lable about using it in a modern engine.
By the way is is #30 with no W. That is because is is not to be used in winter like under 50 degrees. Not a winter oil.
Also not recommended for breaking in a fresh engine.

yeah i buy Non-Detergent Oil from O-Reilly's, ND-30 or ND-40 for my Air Compressor

The reason for that is because air compressors use a splash oiling system rather than a pressure system. A detergent oil would foam up from the splashing and cease to lubricate.

Verne

Verne, that sounds good, but according to a lot of threads on Chatter, 10-30 detergent oil is recommended for the 4 cylinder Chevy engines, and they have a splash oil system. So the theory of foaming seems not to jibe with this recommendation.

One oil dealer told me that a detergent oil will keep contamination particles suspended in the oil so they could be removed by a filter. Engines that had a bypass filter or no filter should use the non-detergent oil so that the contamination particles sink to the bottom of the pan.

Cheers, Dean

My IR compressor came with full synthetic oil. I've changed it once & replaced it with full synthetic. Cheap insurance.

Actually detergent in oils will suspend small particles (like carbon, dust) but not larger ones. Ever see a large particle in an oil filter? No, they are mostly in the oil pan.

Those suspended particles (if there are any) probably won't cause any problems in our old Chevy engines. Besides the particles will theoretically flow through the oil systems (including bearings) in most engines several times before getting caught on the filter media. So to get too paranoid about a few suspended particles is a waste of brain power.

Most detergents that we are familiar with: laundry powder, dish washing "soap", wall washing, etc. primarily help suspend oil and dirt in an aqueous liquid. Secondarily they lower the surface tension so the water will penetrate into places it normally will not go. A side affect is stabilization of bubbles. Detergents in lubricating oils are different animals. Causing oils to foam is not one of those properties. However, if you mix in enough water then they will form a stable oil/water emulsion which has a bunch of tiny bubbles.

Dean,
I have no knowledge of the Chevy 4 cyl engines you refer to or if the engineers specified a detergent oil. But I do know that a detergent oil will foam up if agitated. It's just like putting dish washing liquid in the sink and shaking your fingers in it.

Verne

Chipper,

All good points.

My rule of thumb is to use 10w-30 in all old Chevrolet engines unless there is compelling reason to diviate.

Charlie