Question about the Onan Microlite 2800

I like 15W40 because I like to exercise the generator on warm winter days. If I used it only in summer (80-110 F "cold" temperatures) I would put in a 30 weight, as I do for my other air-cooled engines.

Manual suugests both, for different operating regimes.

1775 wrote:
I change the oil in my Onan 2800 every year at the start of the season.

Consider changing at the end of each season.

Motor oils are corrupted by water ( from condensation forming in the cases), acids ( byproducts of combustion) and gas.
Rather than have your corrupted dirty oil sitting in the cases over the "downtime" replace with fresh at the end of the season.

Ocassionally run your starter motor to move some of the that fresh oil around ( if you have the gasoline supply turned off.)


I would not suggest "exercising" the genny ( if you have a fuel cut off) as when the motor first starts is when the most gas and byproducts will get past the piston rings- parts have not yet expanded to seal- also the hot/cold cycles will cause condensation inside the cases...the motor may not get hot enough to boil out any water.

If you don't have a fuel cut off- then preserving the carb takes priority.

My PW Lexor has an added inline valve I can reach from the left side wheel well




Mike

1775 -thank you for the information.
my local rv dealer says 15-30 .
Before I new thst I used 10-30 this time.

I change the oil in my Onan 2800 every year at the start of the season. We don't use the generator often (it gets more monthly exercise than actual use) and we don't reach a 150 hours in a year. Onan says if not 150 hours in a year then change the oil yearly. There is a chart in the manual for what grade to use - it varies by conditions. The Onan comes with 15W-40 in it. The chart varies by general temperature per location - 32dF and above - SAE 30, 10 dF to 100, SAE 15W-40, 0dF to 80dF - SAE 10W-30 or 10W-40, minus 20dF to 50dF - 5W-30.

We put in 15W-40.

ok, thanks everyone.
I was asking cuz i couldnt find the oil weight in any of the manuals thanks again.

Link to manual if you need:

www.cumminsonan.com/www/pdf/manuals/981-0506.pdf

I don't think a specific oil is in there- I use 20w50 as I am in a warm climate ( and I have a bunch of 20w50 for my motorcycles...)



mike

I checked my notes and I used 15/40 wt. I believe all new Onans are prepped with 15/40.
Depending on where your located, no real extreme temps, 30wt is probably OK.
Do a specific model no. search for your 2800, I think different models had different recommendations.
In KS I would go with 15/40, and like what was mentioned, no longer than a year, or 100 hrs between oil changes.

Manual says every year or 100 hours. A quality 30 weight oil.1 quart.

I would go with what the manual says.