Onan generator oil change

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the 150 hours sounds about right - depending on your use and weather conditions, I would think that once/year might be more than necessary for an Onan. bringing mine in for an oil change, new oil and air filters, clean carb and plugs (whatever else may be included in the camping world basic gas generator service).
its' a 1991 - Onan emerald series 4000 - 494 hours on it now. been a real trooper for the 10 years we've had it. 
I now run it about 45 minutes on the weekend - take the rv for a drive, run the gen and a/c, start the fridge on propane each weekend also - use it - or you'll be fixing it just when you want to use it.
 
i have 4000 onan gas geneator recomend15w40 oil i would like to change to synthetic oil would use the same weight oil or what weight oil should i use
 
billy barksdale said:
i have 4000 onan gas geneator recomend15w40 oil i would like to change to synthetic oil would use the same weight oil or what weight oil should i use
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Use the same weight recommended by the manual for your uses and weather conditions, regardless of conventional vs. synthetic.  In central IL where I live, it can get really hot and really cold but I still fall in the 10W-30 range for my usage (which is rare) so that's what I keep in there when I change oil annually.
 
We took a 3000 mile trip a month or so ago.  It was so durn hot I put almost 90 hours on the genset, running the AC while running down the road, that was over a period of 3 weeks.  Hubby changed the oil when I got home.  I have a feeling mine will have big time hours on it in short order.
 
we got a 1988 airex class A with a 6.5k onan admiral. the filter is about 1 inch from a piece of the body!!  i cant figure out how to change it without removing the whole gen!!
 
The 2004 MicroLite 4000 series operator's manual says to torque the oil drain plug to 21 lbs-ft, whereas the 1997 MicroLite 4000 series operator's manual says to torque the oil drain screw to 5-8 lbs-ft.

I tightened mine as tight as I would ever normally tighten an oil drain plug, and then checked it with a torque wrench, and it was only at about 10 lbs-ft. I then tightened it further to 15 lbs-ft, and felt that if I went any further it might strip the threads.

Could the 21 lbs-ft listed in all of the owner's manuals that I could find be wrong, and the 1997 service manual correct? Anyone have access to a more up-to-date owner's or service manual for the 4000 series? What about other models of Onan generators...what oil drain plug torque is specified for them?


KodiakRV said:
I've got that model and I changed mine a couple of weeks ago.  It's easy as long as the RV manufacturer didn't install it with a brace blocking the drain hole.  The manual instructions say it all...  [my comments in brackets]

1. Run the engine until warm, stop it and remove the oil fill cap.

2. Remove the oil drain hole cover in the base [2 screws], place a pan underneath and unscrew the drain
plug [a hex-head bolt].  Let all oil drain from the engine and then secure the drain plug. Torque the
plug to 21 lbs-ft and secure the cover.

3. Refill with 1.6 quarts (1.5 liters) of oil. See ENGINE OIL RECOMMENDATIONS  [table below].
Check the oil level and add or drain oil as necessary.

4. Screw the oil fill cap back on securely.

TABLE 1-1. OIL VISCOSITY VS. TEMPERATURE
EXPECTED AMBIENT
TEMPERATURES                                  SAE VISCOSITY GRADE
32? F (0? C) and higher --                      30
10? F to 100? F (−12? C to 38? C) --      15W-40
0? F to 80? F (−18? C to 27? C) --          10W-30 or 10W-40
−20? F to 50? F (−28? C to 10? C) --      5W-30
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21 lb-ft seems awful high for an oil drain plug, but they also show 27 n-m and that's the correct metric equivalent. If it's not leaking at 10-15 lb-ft, I would leave it alone. It's not as though the oil is under pressure or anything!
 
Fcranger said:
I think Onan recomends to change the oil in the generator after the first 20 hours of use.
I have not used it very much since I bought it, I have almost 20 hours on it. most of it half hour run times a month to exercise it. haven't had to use it steady since all the campgrounds had electric hookups.
How much of a job is it to change the oil myself? I take the motorhome to Oil Can Henry's for oil changes and they use Mobil 1 synthetic in the engine, is it okay to use the same thing in the generator? its a Onan Microquiet 4000  ???
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Any SJ rated oil or better will work I recommend Mobil 1 10-40 for year around use.
On page 2-5 of the operators Manuel it stats that the unit should be run for 2 hours each month at least half load.
Also on page 3-1 in the periotic maintenance table you will find that you should change your oil at the first 20 hours then every 150 hours but at least annually.
The number one thing that causes problems with generators is lack of use or exercise.
I would be doing an oil change as you say you have 20 hours on the new generator.
Bill
 
sorry for derailing, but something that I've scratched my head about is the whole running with 50% load thing.  About the only way I can put that kind of load on mine is to run the AC...... doesn't make much sense to me...... for a fixed 2 hours per month especially without short runs
what i can do is run it for a period of time, maybe 10-15 minutes, 20 minutes, maybe an hour or more on occasion.  Sometimes I would have the AC on, but sometimes, like now the load would be a little battery charging and lights etc....  Sometimes I start the genny for just a minute, to check the hobbs meter or brew a cup of coffee

One our recent long trip, we ran a total of approx 15 hours on the genny.  It was up and down.  Sometimes only for a few minutes, sometimes for more than an hour.  Just normal living.  Is that really bad for it?

NOW, Back to this thread topic, I was actually planning on looking in the manual this weekend to confirm the service intervals to see if I'm due for anything.  Currently just under 28 hours total on it, and had the dealer change the oil when I bought it since it had been sitting on the lot for a year....... so based on this thread, I guess I'm good for now!
 
blw2 said:
sorry for derailing, but something that I've scratched my head about is the whole running with 50% load thing.  About the only way I can put that kind of load on mine is to run the AC...... doesn't make much sense to me...... for a fixed 2 hours per month especially without short runs
what i can do is run it for a period of time, maybe 10-15 minutes, 20 minutes, maybe an hour or more on occasion.  Sometimes I would have the AC on, but sometimes, like now the load would be a little battery charging and lights etc....  Sometimes I start the genny for just a minute, to check the hobbs meter or brew a cup of coffee

One our recent long trip, we ran a total of approx 15 hours on the genny.  It was up and down.  Sometimes only for a few minutes, sometimes for more than an hour.  Just normal living.  Is that really bad for it?

NOW, Back to this thread topic, I was actually planning on looking in the manual this weekend to confirm the service intervals to see if I'm due for anything.  Currently just under 28 hours total on it, and had the dealer change the oil when I bought it since it had been sitting on the lot for a year....... so based on this thread, I guess I'm good for now!
Click to expand...

Brad are you saying 28 hours since new or since you bought it/last oil change? Onan recommends first oil change at 25 hours then 150 or annually. I recommend Mobil 1 10-40 for year round protection.
As to your hurting it by using it for short runs. I would say it would be similar to doing a lot of in town stop and go short trip driving in your car. I think if you do some longer runs for say 30min to an hour mixed in you should be ok. Basically you need to get the engine and especially the generator up to temp. To do this it should be run at 1/2 to 3/4 load.
Bill 
 
When I lived up north I ran my old 4000 Onan 1/2 hour or more on a 4 to 6 week schedule. I ran it when futzing about outside, yardwork, tinkering, shoveling snow. Warm weather run an ac, winter weather run a space heater, brew a pot of coffee and keep it warm both seasons. Nice place to take a break and cool off or warm up. The genny is original in a 1993 Bounder, meter shows low hours for 21 years, only 380 hours.

Bill
 
blw2 said:
sorry for derailing, but something that I've scratched my head about is the whole running with 50% load thing.  About the only way I can put that kind of load on mine is to run the AC...... doesn't make much sense to me...... for a fixed 2 hours per month especially without short runs
what i can do is run it for a period of time, maybe 10-15 minutes, 20 minutes, maybe an hour or more on occasion.  Sometimes I would have the AC on, but sometimes, like now the load would be a little battery charging and lights etc....  Sometimes I start the genny for just a minute, to check the hobbs meter or brew a cup of coffee

One our recent long trip, we ran a total of approx 15 hours on the genny.  It was up and down.  Sometimes only for a few minutes, sometimes for more than an hour.  Just normal living.  Is that really bad for it?
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You are doing exactly what the manual says not to do.

Exercising the generator isn't all that difficult. In the summer, I run the A/C. In the winter, a couple of small heaters.
 
blw2: If it's too cold to run the a/c for awhile, plug in an electric heater instead. Or brew a pot of coffee. The idea is to load the electrical generation components enough to heat them up a bit and drive out any accumulated moisture. That's in addition to running the genset engine long enough to warm up the oil to normal operating temperature.
 
PLEASE DON'T HIJACK MY THREAD NEXT TIME.

blw2 said:
sorry for derailing, but something that I've scratched my head about is the whole running with 50% load thing.  About the only way I can put that kind of load on mine is to run the AC...... doesn't make much sense to me...... for a fixed 2 hours per month especially without short runs
what i can do is run it for a period of time, maybe 10-15 minutes, 20 minutes, maybe an hour or more on occasion.  Sometimes I would have the AC on, but sometimes, like now the load would be a little battery charging and lights etc....  Sometimes I start the genny for just a minute, to check the hobbs meter or brew a cup of coffee

One our recent long trip, we ran a total of approx 15 hours on the genny.  It was up and down.  Sometimes only for a few minutes, sometimes for more than an hour.  Just normal living.  Is that really bad for it?

NOW, Back to this thread topic, I was actually planning on looking in the manual this weekend to confirm the service intervals to see if I'm due for anything.  Currently just under 28 hours total on it, and had the dealer change the oil when I bought it since it had been sitting on the lot for a year....... so based on this thread, I guess I'm good for now!
Click to expand...
 
soyjer said:
PLEASE DON'T HIJACK MY THREAD NEXT TIME.
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I believe Gary answered your question on January 10th. Posting a reply like you just did will not make you many friends. All you would have needed to do was post the question again maybe in a different way.  :mad:  ::)  Have a nice day.  ;)
 
Rene T said:
I believe Gary answered your question on January 10th. Posting a reply like you just did will not make you many friends. All you would have needed to do was post the question again maybe in a different way.  :mad:  ::)  Have a nice day.  ;)
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X2.  Some of the most informative and interesting posts on this forum are the result of "hijacked"  threads.
 
I am trying to get this straight soyjer.  You didn't post till 27 post after this thread was started by Fcranger. You technically "HIJACKED" the thread and now you act like, well I am not permitted to say. As they say on Shark Tank "I am out" on any future post you make.
Bill
 
WILDEBILL308 said:
I am trying to get this straight soyjer.  You didn't post till 27 post after this thread was started by Fcranger. You technically "HIJACKED" the thread and now you act like, well I am not permitted to say. As they say on Shark Tank "I am out" on any future post you make.
Bill
Click to expand...

I guess we should cut him a little slack. He just needs to learn. He only registered this past July.
 
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