rvupgradestore.com Composet Products Fridge Defend
RV Life Magazine RV Park Reviews RV Trip Wizard

Author Topic: onan 7500 quiet diesel gen  (Read 247 times)


  • ---
  • Posts: 38
onan 7500 quiet diesel gen
« on: July 23, 2017, 09:39:32 PM »
I am going to change coolant, belts and hoses on my gen set. anyone know of a web site with good written instructions for a onan 7500 quiet diesel gen?  have watched some good videos but would like yo have the written word with me when I do it.  any pertinent info would also be appreciated.
2007 tiffin phaeton


Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 65360
  • RVer Emeritus
Re: onan 7500 quiet diesel gen
« Reply #1 on: July 24, 2017, 11:29:47 AM »
How about the service manual?


Onan's Generator Handbook has lots of service tips and diagrams as well:

And don't forget your Onan owner manual for a detailed diagram showing where everything is located and accessed.

The biggest problem with a coolant change is air in the lines. Very difficult to avoid and it prevents coolant circulation so that the genset overheats (shutdown) in about 5 minutes. May have to disconnect lines to burp them, but sometimes repeated warm-up & cool-down cycles gradually works the air out  and you can then add more coolant. If you cannot get the radiator to take the required amount of coolant initially, you will have to struggle with this. Don't worry - the Onan won't let any harm occur.
« Last Edit: July 24, 2017, 11:33:54 AM by Gary RV_Wizard »
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL