Onan Oil?

[Mike and Amy]

I am getting ready to do generator maintenance and was wondering what oil others are using in their 7500 diesel? I am also changing the oil filter, air filter, and fuel filter, probable will clean the spark arrester too. The gen. only has 220 hours, but I want to start fresh with everything since it is all "new" to me. Thanks for any suggestions. Mike

[Caemlyn]

I use the same Shell Rotella T I use in the engine.

[RJay]

Ditto, Shell Rotella 15W-40 make sure it has an ASE rating of CJ-4.

[Tha_Rooster]

I use Onan filter, rotella T 15-40 oil

[Old Scout]

Unless you think the genset was "used and abused," the only thing that is "required/ desired" to be changed at this point is the engine oil [3 qrts/15-40] and filter [every 150 hrs or annually]. Air and fuel filters are good for 500 hours. Kind of engine oil is open for debate--people swear by Rotella; get Onanmax at Cummins, not Camping World; if you are going with Valvoline Blue in your Cummins, then buy an extra gallon for the genset; oil filter at Cummins {122-0833} or Fram at Walmart{PH3593A} but again, not at CW; and coolant every 3-5 years [Complete ES or any brand name E/L will do].

PS -- Onan/Cummins has a great website on all things Onan.

[Mike and Amy]

Looks like Rotella gets the most votes, Have any of you tried the new synthetic Mobil 1 for Diesels? I am changing all the filters because the Alpine is a 2005 and I just want to start fresh....just finished changing the fuel filter, had to take the exhaust bracket off to get to it and the oil filter....Thanks for all the input....Mike.

[Old Rv'er]

I used Chevron Delo 15W-40 in diesel trucks for twenty years, with no problems. The federal agency I retired from used it in all the heavy duty line trucks we used to maintain the High Voltage Substations in the Pacific NW, so if it kept those rigs running, it's what I used. Oil is like washing machine soap, everyone has the brand they like, but make sure you use the correct "Diesel Rated Oil" specification. The owner’s manual says-“Onan Models HDKAH; HDKAJ; HDKAK; HDHAT; HDKAU; HDKAV-Spec A-M says: API Performance Class CH-4, CG-4 or CF-4 engine oil which may be in combination with performance Class SJ, SH or SG”. However, since USLD, the specifications have been changed, and if you read the carton of the oil, it will say it meets Cummins specification, blah, blah & blah. That means the oil meets Cummins specification for the engine, and genset diesel. Any good brand named oil Delo, Rotella, Valvoline Blue that is correctly rated for diesel engines will work fine. The hour’s interval is as stated above, 150 hours of operation for an oil change, and 500 hours for the air filter. But you also should exercise the genset two hours a month, and lots of people don’t do that. I change both diesels once a year.

[RogerBall]

I too went out to the rig to change the generator oil last weekend. Found out that with the generator fully extended, the rail rollers block the oil filter access door and keep it from opening. So then I retracted it and found the exhaust pipe was now in the way. Had to remove both the exhaust pipe and it's support bracket in order to get the door open. What a great design!
Fortunately, the oil filter was relatively easy to remove. Used Delo 400 as well.

Trying to get everything checked out for the FMCA rally in Albany, Or. in two weeks. Will be the first time running fully self contained since getting the rig. (Hope the Aqua Hot doesn't smoke everyone out.!).

Ron&Jean
'07 36 FDTS

[Fix it Dave]

Thanks for the info on the oil filter 122-0833. My Winnebago Itasca Horizon requires that the generater oil filter access door screws be removed to gain access to the oil filter. Way to go Winnebago. These are the two torix screws at the end of the EZ open door with a latch.

[rebelone]

On my Onan 7500 the bottom access door swings down when to catches are pressed. The door can be removed by lifting up at the hinge end. Makes it easy to remove filter.

[zinom]

Mike, The fuel filter fitting can be kinda' tight to get to. Scope it out before you start....could be a good excure for a new tool! Good Luck, Matt

[Old Scout]

Loosen the fuel filter bracket or filter set screw first then loosen the fuel line connections. Reconnect lines to new filter first then secure filter in bracket. Careful, you can easily cross-thread the fuel line connections or round the corners.

[dagray]

I will probably get a lot of heat for this post because many people have ideas about what is the best oil. I have been told by good mechanic and friend that as long as the oil meets all the proper specifications the best oil is clean oil. It doesn't matter what brand you use.

[Hurricane Owner]

Look in the owners manual, it has the specs for different temperatures. Onan site also has the manual, you can download it. It also list the maintenance schedule in the owners manual. Take a look at it, and decide whats best for you.