I’m trying to find the oil capacity and what type of oil to use for a Dayton Speedaire air compressor 3Z419?
I did find a photo of one and uploaded it for all to see, just above.
Note the plug on the right of the photo on the base of the pump. That’s either the fill or the drain, I cannot tell which. Check for another plug either above or below this one. The lower will be the oil drain plug, the higher the fill plug.
If only one plug, then I guess to drain the oil it would be necessary to tip the compressor. Odd if that’s the case, but if so, this isn’t the only compressor that requires that to get the oil out.
I suspect it will take less than a quart to fill, and you do want to be careful as you do, that you don’t overfill, as that brings with it its own series of problems.
If you buy either compressor rated lubricating oil at the store, or a 30 W (not 5w-30 or 10w-30, but just 30 weight) none detergent oil, you should be OK.
Why not contact Grainger too and get the specialists recommendation? They own the Speedaire brand and someone may remember this model or have the specs.
If they send you the specs or manual in digital form, why not upload them using the form and I’ll put them up for all to have and download?