Did an oil change on the Onan Microquiet 4000 and sent in an oil sample for analysis. Got the result back and looks good. Iron is a little higher than average, the average duration is 100 hrs. and I ran 42 hrs., but it still has low hours so may be still breaking in.I had run this oil, Mobil 1 High Mileage 10W-40 for 2 years, 4 months and decided it was time to change. Did not look all that dirty and looked like it could have gone much longer, however the oil had sheared down into the 10W-30 weight range.TBN looked good, plenty of acid absorbing capability left.Had some leftover 0W-40 so that is in there now.

I always find these interesting. Some diesel guys really get into testing engine oil.Thanks for sharing

It is my understanding that the first test merely establishes a baseline for subsequent analysis. Changing oil and duration would skew the results.

The universal averages for all users with this type of motor is in the right column, based on an average of 100 hrs of use. So some comparison is possible. I'm surprised how much oil shearing there was, that oil should have started out with 14.7 cSt and it sheared down to 10.55.I have run the same type of oil in our cars in the 10W-30 weight and over a 4200 mile run it only shears from 12 cSt to 11.15 or so.

Since the Micro's don't have an oil pump or filter (splash lubed), and are air cooled (higher oil temps?), they may well impose higher stresses on the oil than a car engine.Jim, "I couldn't fix your brakes, so I made your horn louder."

It would be interesting to see how much the 0W40 shears. I have that in my Onan. Am I correct in reading that the 10W40 sheared into a heavy 30 weight?

Onan Microquiet 4000 Oil Analysis | Good Sam Community

16 Replies

RambleOnNW
Explorer II
Aug 05, 2014
Viscosity at 100 deg C, 30 weight range is 9.3 - 12.49 cSt, 40 is 12.5 - 16.29. The 10w-40 HM started with 14.7, Mobil 1 0W-40 starts with 13.5.

For comparison, Mobil 1 10W-30 starts with 10.1, 10W-30 EP starts with 10.2, so yeah, ended up a little higher but wouldn't call it a heavy 30 weight. Mobil 1 10W-30 HM starts with 12 cSt.

Will check back in a couple of years on the 0W-40...
tpi
Explorer
Aug 05, 2014
It would be interesting to see how much the 0W40 shears. I have that in my Onan. Am I correct in reading that the 10W40 sheared into a heavy 30 weight?
Handbasket
Explorer
Aug 05, 2014
Since the Micro's don't have an oil pump or filter (splash lubed), and are air cooled (higher oil temps?), they may well impose higher stresses on the oil than a car engine.

Jim, "I couldn't fix your brakes, so I made your horn louder."
RambleOnNW
Explorer II
Aug 05, 2014
The universal averages for all users with this type of motor is in the right column, based on an average of 100 hrs of use. So some comparison is possible. I'm surprised how much oil shearing there was, that oil should have started out with 14.7 cSt and it sheared down to 10.55.

I have run the same type of oil in our cars in the 10W-30 weight and over a 4200 mile run it only shears from 12 cSt to 11.15 or so.
Jaxom
Explorer
Aug 05, 2014
It is my understanding that the first test merely establishes a baseline for subsequent analysis. Changing oil and duration would skew the results.
wcjeep
Explorer
Aug 05, 2014
I always find these interesting. Some diesel guys really get into testing engine oil.

Thanks for sharing

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Onan Microquiet 4000 Oil Analysis

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