diesel gen. oil change

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havgoods

Member
Joined
Jan 11, 2010
Posts
22
Location
lake havasu city
can someone tell me how much oil a 7500 quite diesel  generator holds, and what filter to use. I thought I would save some money by doing the oil change myself.
 
The Onan QD 7500 use 3 quarts of oil and most people use the same 15W40 used in the coach diesel engine. The filter is an Onan 122-0833 (replaces the original 185-5409) and the NAPA 1064 is equivalent.

The air filter is an Onan 140-2897 and the fuel filter is an Onan 149-2513, with the  NAPA 3063 or Wix 33063 as equivalents for fuel.
 
Gary and Tom have some good info. There is no reason you can?t do your own oil changes on your generator. I would make a quick reference list with all the part numbers so you will have them next time. I keep a copy in the RV as well. I would also add the serial numbers for your generator, engine, coach and transmission.
The only thing I do differently is I use Mobil-1 5-40 Turbo Diesel Truck in both the gen and the MH.
Hear is a video that may help you
http://www.youtube.com/watch?v=CxqkHAAH818
I would use some anti seize on the spark arrestor plug if it was me. I also believe it is important to use a low silica antifreeze in the radiator.
Bill
 
I'll warn you, though, that changing the fuel filter on a QD7500 or 8000 is a real PAIN! You have two get two wrenches up into a tiny recess on the bottom, while lying on your back with diesel dripping down your arm.

The oil filter is in a recess underneath too, but it's just a spin-on and not difficult.

My genny oil gets changed every year when I do the chassis engine oil change, but the genny fuel filter gets changed only once in great awhile.
 
Anything rated for diesel cooling systems. Fleetguard has several. If it doesn't say diesel somewhere on the container, I would shy away from it.

Here is an excellent article of diesel coolants by a knowledgeable RV owner http://www.rvcruzer.com/coolant.php?p:
 
I would recommend the OAT coolants as I had a problem with my Onan or I should say the dealer had a problem. The generator was overheating. The dealer had to remove it and take it to the local Onan dealer to have it checked out. They had to replace the radiator as it was plugged with crystals. I have been told the crystals form when the generator isn?t run enough. Just one more reason to exercise your Onan.
Bill
 
Just changed oil and filter in my onan 7500 and found 3 quarts is not enough.  Have 3.5 qts and still need more although everything I read says 3 qts with filter.  Any thoughts?
 
Tanner said:
Just changed oil and filter in my onan 7500 and found 3 quarts is not enough.  Have 3.5 qts and still need more although everything I read says 3 qts with filter.  Any thoughts?
Click to expand...

Tanner, welcome to the forum. Just a little friendly advice. Start your own post on this issue. It saves everyone from reading a entire post especially if it's  almost 5 years old like this one. 
 
havgoods said:
can someone tell me how much oil a 7500 quite diesel generator holds, and what filter to use. I thought I would save some money by doing the oil change myself.
Click to expand...
3 quarts with filter exact amount:
HOT CLIMATE 15w40
Normal MOST conditions 5w30
  • Air Filter Onan PN: 140-2897
  • Fuel Filter Onan PN: 149-2513
  • Oil Filter Onan PN: 122-0833
I have 2720 hours on my 7500

It runs like new.

If you live in a VERY hot climate use the same oil as your Cummins (15w40)

However I live at the 40th parallel north which is a circle of latitude that is 40° degrees north of the Earth's equatorial plane. For gardening reference this is growing zone 5/6ish

I can tell you for certain, you want to use Mobil 1 5W30 in this zone.

Otherwise it causes serious low temp staring and running problems.

I change my oil and filter every year.
The generator is a highly reliable piece of equipment that is extremely expensive to replace when not maintained.
 
Max Reilly said:
3 quarts with filter exact amount:
HOT CLIMATE 15w40
Normal MOST conditions 5w30
  • Air Filter Onan PN: 140-2897
  • Fuel Filter Onan PN: 149-2513
  • Oil Filter Onan PN: 122-0833
I have 2720 hours on my 7500

It runs like new.

If you live in a VERY hot climate use the same oil as your Cummins (15w40)

However I live at the 40th parallel north which is a circle of latitude that is 40° degrees north of the Earth's equatorial plane. For gardening reference this is growing zone 5/6ish

I can tell you for certain, you want to use Mobil 1 5W30 in this zone.

Otherwise it causes serious low temp staring and running problems.

I change my oil and filter every year.
The generator is a highly reliable piece of equipment that is extremely expensive to replace when not maintained.
Click to expand...
Hi and welcome.

You probably didn't notice but this thread is 10 years old. As a new member you will see a lot of old threads. No problem in responding to these but some may now be irrelevant.
 
My class A Fleetwood American Dream is going on 25 years old.

I’m just reinvigorating accurate relevant maintenance information.

Bellow is the factory specs of my 7500 onan diesel generator running like new with 2720 hours on the clock.

This generator will last over 10,000 hours if maintained correctly.

1697177996012.jpeg
jackiemac said:
Hi and welcome.

You probably didn't notice but this thread is 10 years old. As a new member you will see a lot of old threads. No problem in responding to these but some may now be irrelevant.
Click to expand...
y
 
Max Reilly said:
3 quarts with filter exact amount:
HOT CLIMATE 15w40
Normal MOST conditions 5w30
  • Air Filter Onan PN: 140-2897
  • Fuel Filter Onan PN: 149-2513
  • Oil Filter Onan PN: 122-0833
I have 2720 hours on my 7500

It runs like new.

If you live in a VERY hot climate use the same oil as your Cummins (15w40)

However I live at the 40th parallel north which is a circle of latitude that is 40° degrees north of the Earth's equatorial plane. For gardening reference this is growing zone 5/6ish

I can tell you for certain, you want to use Mobil 1 5W30 in this zone.

Otherwise it causes serious low temp staring and running problems.

I change my oil and filter every year.
The generator is a highly reliable piece of equipment that is extremely expensive to replace when not maintained.
Click to expand...

Welcome, Max. I'd caution other readers to consult the temperature chart for different oil weights based on where they use their generators. I live north of the 45th, but far enough West that we don't get those cold temperatures that you do in the Southern latitudes ;)

I'd also caution with the thinner weights often used in gasoline engines to make sure the oil is also formulated for diesel engines. Mobile 1 ESP 5w30 is formulated for both diesel and gas, but I'm not sure that all 5w30's are.
 
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