jamesgangnc wrote:
On Jun 9, 3:24 pm, J Burns wrote:
A decal on my furnace blower seemed to say the motor was permanently
lubricated. The other day I got my head a little lower and saw a second
decal saying it should be lubricated every couple of years with 20W
nondetergent oil.

I think 3-in-1 is like that, but I can't find my can. I did find a
4-ounce container of Marvel Lubricating Oil. Among the uses listed on
the label is "small electric motors."

Small is relative. Would Marvel Lubricating Oil be good for a furnace
blower?

I'd say it's a bit thin. My walmart has 30wt nondetergent. I'd
probably lean that way if I couldn't find 20wt. Nondetergent also
gets used in things like pressure washers.

Thanks, it looks as if you and Salty Dog are right.

One way to measure viscosity of motor oil is cSt at 40C. CSt is a
measure of the number of seconds it takes a certain amount to drain
through a certain tube.

At 40C, the cSt of 10W should be 25-35
20W 40-80
30 80-120

I have a fresh can of 10W-30, a remnant of 30W nondetergent in a can I
bought last year, and a little 20W-50 in a can several years old. I
started with the 10W-30 because it's the freshest.


seconds at 25C
10W30 22
20W50 40
30W 47



If the 10W30 has a cSt about 30, the 20W-50 has a cSt of 55. So far, so
good. The 30W ND seems to have a cSt of 64, like 20W oil. So maybe
that brand of 30W could pass for 20W.

The Marvel Lubricating Oil? Three seconds!