We just purchased a new motorhome recently. I noticed in the owners manual for the generator that they suggested the first oil change to be done at 20 hours. I already had about 25 hours on the generator so I decided to change the oil this weekend. I ran the generator for about 45 minutes running both AC units to get the genset up to temperature. I was able to easily drain the oil and change the oil filter. I couldn't believe how easy it was to change the oil! That was before I started filling the generator with 2 quarts of oil.First quart went in OK and then the first half of the second quart went in OK. It took me about 30 minutes to get that last 1/2 quart in the generator. If I poured too much, oil would come out of the fill port and make a mess running down the side of the generator. My legs are still sore from being crouched down next the the generator trying to slowly add the oil. I guess next time I will fill the oil filter first and maybe that will help. Any suggestions for the next oil change?It doesn't appear that you can overfill with oil since the oil will just spill out the oil port if you put too much in. I was starting to think I was trying to add to much oil but the label on the generator said 2 quarts.Burch

Label on the Gen reads two qrts.What does the manual read ? 2 qrts dry or 2 qrts with oil filter ?If the oil filter is mounted vertical then yes fill the filter up as much as possible. If its mounted horizontal you could add some in and spin it on fast ...On our onan gen there is no filter... Thought that was odd !

What you might try is to put in the 1st qt then part of the second qt start and stop generator (30 sec) then add the rest of the second qt. Reason I say this I had a Yamaha Road Star motorcycle, it had a oil tank and per instructions put in the 1st qt put cap on the tank then start rev it up a couple of times. That would force the 1st qt into the crankcase then add the 2nd qt and good to go.

F-TROUP wrote:What you might try is to put in the 1st qt then part of the second qt start and stop generator (30 sec) then add the rest of the second qt. Reason I say this I had a Yamaha Road Star motorcycle, it had a oil tank and per instructions put in the 1st qt put cap on the tank then start rev it up a couple of times. That would force the 1st qt into the crankcase then add the 2nd qt and good to go.That's basically what I did. I got a little more than half the 2nd quart in and then started the gen for 10-15 seconds. That did help a little but it still took a long time to get the rest of the oil in.

I get about 1.5 quarts in mine when it is "full". Put the dip stick back in (don't forget to do this or you will be wearing oil-Yep, I did it once) and turn the engine over even if it doesn't start. Remove the dip stick and add some more. I only have to do this a time of two and the second half of the second quart is in. Easy to do, just don't forget to put the dip stick back in before each short turn over/run. It does make a mess right in your face.

MetalGator wrote:We just purchased a new motorhome recently. I noticed in the owners manual for the generator that they suggested the first oil change to be done at 20 hours. I already had about 25 hours on the generator so I decided to change the oil this weekend. I ran the generator for about 45 minutes running both AC units to get the genset up to temperature. I was able to easily drain the oil and change the oil filter. I couldn't believe how easy it was to change the oil! That was before I started filling the generator with 2 quarts of oil.First quart went in OK and then the first half of the second quart went in OK. It took me about 30 minutes to get that last 1/2 quart in the generator. If I poured too much, oil would come out of the fill port and make a mess running down the side of the generator. My legs are still sore from being crouched down next the the generator trying to slowly add the oil. I guess next time I will fill the oil filter first and maybe that will help. Any suggestions for the next oil change?It doesn't appear that you can overfill with oil since the oil will just spill out the oil port if you put too much in. I was starting to think I was trying to add to much oil but the label on the generator said 2 quarts.BurchI have never had to start it or turn it over to get in the 2 quarts, but yes the last 1/2 quart is slow going.

First Oil Change Onan 5500 | Good Sam Community

11 Replies

edatlanta
Explorer II
Sep 04, 2017
camper19709 wrote:
MetalGator-----what you experienced is normal. I fill the new filter before installing and it helps a great deal. Yes, that last half quart is a slow process. I use a small stool to sit while i change the oil. Sitting makes it less stressful "slowly" adding that last bit of oil. It takes 2 quarts and yes you can overfill. Just keep an eye on the dipstick level. My Onan 5500 has 2200 hours on it.

I happy to see your total hours. My 5500 has 450 hours on it so I have a good long life ahead. I do run in each and every month for an hour with a load on it and keep stabilizer in the gas. So far it has never failed me.
ford_truck_guy
Nomad
Aug 30, 2017
MY Onan 6500 has the same issue...

With it being my first Onan, I stopped by the local Cummins/Onan facility to ask the techs.. They told me it was normal, but it will take ALL 2 guarts
MetalGator
Nomad
Aug 30, 2017
Cummins12V98 wrote:
Not sure what would be different but my Commercial 6500LP was easy to fill with required amount of oil.

BTW 15 min would have been plenty long running with a load to fully heat the gen.

I have two other generators (one being a 8K commercial) and they were easy to change. It just took forever to get that last 1/2 quart in. Had to go VERY slow or it would overflow. Next time I will use a small stool as my legs were killing me from squatting down next to the generator compartment under the slide!

The owners manual said to run 30 minutes to normal operating temperature. I ran it around 45 minutes to an hour because I was inside the motorhome doing some cleaning and needed the AC units running in the hot Florida sun.

Burch
Cummins12V98
Explorer III
Aug 30, 2017
Not sure what would be different but my Commercial 6500LP was easy to fill with required amount of oil.

BTW 15 min would have been plenty long running with a load to fully heat the gen.
MetalGator
Nomad
Aug 30, 2017
camper19709 wrote:
MetalGator-----what you experienced is normal. I fill the new filter before installing and it helps a great deal. Yes, that last half quart is a slow process. I use a small stool to sit while i change the oil. Sitting makes it less stressful "slowly" adding that last bit of oil. It takes 2 quarts and yes you can overfill. Just keep an eye on the dipstick level. My Onan 5500 has 2200 hours on it.

I am curious how you can overfill. When the Onan has the full 2 quarts, the oil is almost to the top of the fill port. If you put any more oil in, the oil overflows. The "full" indicator on the small dipstick is right at the top of the oil cap.

I sure did make a mess with this first change but at least I know what to expect for the second oil change.

Burch
camper19709
Explorer
Aug 30, 2017
MetalGator-----what you experienced is normal. I fill the new filter before installing and it helps a great deal. Yes, that last half quart is a slow process. I use a small stool to sit while i change the oil. Sitting makes it less stressful "slowly" adding that last bit of oil. It takes 2 quarts and yes you can overfill. Just keep an eye on the dipstick level. My Onan 5500 has 2200 hours on it.
cummins2014
Explorer
Aug 29, 2017
MetalGator wrote:
We just purchased a new motorhome recently. I noticed in the owners manual for the generator that they suggested the first oil change to be done at 20 hours. I already had about 25 hours on the generator so I decided to change the oil this weekend. I ran the generator for about 45 minutes running both AC units to get the genset up to temperature. I was able to easily drain the oil and change the oil filter. I couldn't believe how easy it was to change the oil! That was before I started filling the generator with 2 quarts of oil.

First quart went in OK and then the first half of the second quart went in OK. It took me about 30 minutes to get that last 1/2 quart in the generator. If I poured too much, oil would come out of the fill port and make a mess running down the side of the generator. My legs are still sore from being crouched down next the the generator trying to slowly add the oil. I guess next time I will fill the oil filter first and maybe that will help. Any suggestions for the next oil change?

It doesn't appear that you can overfill with oil since the oil will just spill out the oil port if you put too much in. I was starting to think I was trying to add to much oil but the label on the generator said 2 quarts.

Burch

I have never had to start it or turn it over to get in the 2 quarts, but yes the last 1/2 quart is slow going.
edatlanta
Explorer II
Aug 29, 2017
I get about 1.5 quarts in mine when it is "full". Put the dip stick back in (don't forget to do this or you will be wearing oil-Yep, I did it once) and turn the engine over even if it doesn't start. Remove the dip stick and add some more. I only have to do this a time of two and the second half of the second quart is in. Easy to do, just don't forget to put the dip stick back in before each short turn over/run. It does make a mess right in your face.
MetalGator
Nomad
Aug 28, 2017
F-TROUP wrote:
What you might try is to put in the 1st qt then part of the second qt start and stop generator (30 sec) then add the rest of the second qt. Reason I say this I had a Yamaha Road Star motorcycle, it had a oil tank and per instructions put in the 1st qt put cap on the tank then start rev it up a couple of times. That would force the 1st qt into the crankcase then add the 2nd qt and good to go.

That's basically what I did. I got a little more than half the 2nd quart in and then started the gen for 10-15 seconds. That did help a little but it still took a long time to get the rest of the oil in.
F-TROUP
Explorer
Aug 28, 2017
What you might try is to put in the 1st qt then part of the second qt start and stop generator (30 sec) then add the rest of the second qt. Reason I say this I had a Yamaha Road Star motorcycle, it had a oil tank and per instructions put in the 1st qt put cap on the tank then start rev it up a couple of times. That would force the 1st qt into the crankcase then add the 2nd qt and good to go.