Does anyone know a resource to learn how to change the generator oil in my cummins generator 7500? I would like to learn to do by myself and the one thing I was told to make sure that I use the exact amount of oil to replace what is removed. Thanks for any information

The Onan 7500KW genset uses exactly 3 quarts of oil. Just remove the drain plug (threaded plug) on the bottom of the genset, drain the oil. Remove the oil filter (inside the little access door on the bottom of the genset), and replace with a new filter. Fill with 3 qts of oil.I always use the same oil I use in the coach diesel engine, 15W40.

The access door to the oil filter is hinged, just push the 2 release tabs with your fingers to open. The drain plug is labeled "oil drain" It is easy to do, go for it! I hope this helps, Bill

Remember to wipe a little clean oil on the new filter gasket.

JackMS wrote:Remember to wipe a little clean oil on the new filter gasket.Also make sure the old gasket came of with the old filter. My Onan owner's manual states the the new filter may be a little smaller than the original filter; my replacement filter was slightly smaller than the original filter.Ray

I took my oil filter to Napa auto parts and they gave me a matched filter to replace the original Onan filter. I use Shell Rotella 15-40 in the engine and the Onan Gen set. I put in 2 1/2 qts and run generator several minutes and then check and top off. Don't over fill!! The manual says to replace the coolant plug every 2 years and you can buy @ any cummins dealer.

Changing oil on a diesel cummins generator | Good Sam Community

11 Replies

msmith1199
Explorer II
Jul 03, 2013
Clicky for Video

This is a good video that answers your questions.
jtfcons
Explorer
Jul 03, 2013
I know on my set-up it's neccessary to undo the exhaust pipe hanger for the generator and swing the pipe out of the way to get the hinged door all the way open. I have also found it better to remove the two screws that hold the door to the hinge and get that totally out of the way. Gives better access.
JR45
Explorer
Jul 03, 2013
This may help
http://www.youtube.com/watch?v=CxqkHAAH818
JR
Raymon
Explorer
Jul 03, 2013
rbanuchi wrote:
Everyone , thanks so much for your input. It's truly appreciated I have a stupid question though. When refilling the oil, does it get filled directly into the spout on top There are two spouts one for oil and a second one slips my mind at the moment. Thank you again !

You add the oil into the dipstick tube. The other tube is for the coolant.

Ray
rbanuchi
Explorer
Jul 03, 2013
Everyone , thanks so much for your input. It's truly appreciated I have a stupid question though. When refilling the oil, does it get filled directly into the spout on top There are two spouts one for oil and a second one slips my mind at the moment. Thank you again !
YC_1
Nomad
Jul 03, 2013
The filter can be a bear to remove so buy a new filter and a tool that goes over then end of the filter that you can run a 3/8 inch extension to and use a ratchet. Do not overtighten the new one. Just snug and then about 1/4 turn.
Snomas
Explorer
Jul 03, 2013
I took my oil filter to Napa auto parts and they gave me a matched filter to replace the original Onan filter. I use Shell Rotella 15-40 in the engine and the Onan Gen set. I put in 2 1/2 qts and run generator several minutes and then check and top off. Don't over fill!! The manual says to replace the coolant plug every 2 years and you can buy @ any cummins dealer.
Raymon
Explorer
Jul 03, 2013
JackMS wrote:
Remember to wipe a little clean oil on the new filter gasket.

Also make sure the old gasket came of with the old filter. My Onan owner's manual states the the new filter may be a little smaller than the original filter; my replacement filter was slightly smaller than the original filter.

Ray
JackMS
Explorer
Jul 03, 2013
Remember to wipe a little clean oil on the new filter gasket.
barnaclebill
Explorer
Jul 03, 2013
The access door to the oil filter is hinged, just push the 2 release tabs with your fingers to open. The drain plug is labeled "oil drain" It is easy to do, go for it! I hope this helps, Bill