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ninos · 05-15-2011, 06:52 PM

On my discovery I have an onan 7500 diesel and I changed the colant, took out about one gallon now when I tryed to fill it back up it only took half galon, does anybody know how to bleed the coling system on this diesel generators because I must have major air pockets in the colling system, any info will be apreciated. Joe

KIX · 05-15-2011, 07:04 PM

Joe,
First thing is to pull the radiator cap out until the hose it's attached to is fully extended. Then refill coolant, then leave the cap off and run the genset and add coolant as the level recedes. When you think you have it bled then run with the cap tightened for several minutes. Stop the genset and allow to cool. Then do the run with cap off again and refill as needed.

ninos · 05-15-2011, 08:06 PM

Quote:

Originally Posted by KIX

Joe,
First thing is to pull the radiator cap out until the hose it's attached to is fully extended. Then refill coolant, then leave the cap off and run the genset and add coolant as the level recedes. When you think you have it bled then run with the cap tightened for several minutes. Stop the genset and allow to cool. Then do the run with cap off again and refill as needed.

you got me lost the only thing I see is the colant reservor with the plastic cap, how do i get to the radiator?

KIX · 05-15-2011, 10:13 PM

Quote:

Originally Posted by ninos

you got me lost the only thing I see is the colant reservor with the plastic cap, how do i get to the radiator?

First thing is to pull the radiator cap out until the hose it's attached to is fully extended.

Remove the small panel near the oil and coolant caps to access the cap for the coolant.

Consult your manual. Sounds like you simply poured coolant into the overflow bottle.

AFChap · 05-15-2011, 10:31 PM

Kix has you on the right track ...when I had my coolant changed by an experienced shop I had trouble keeping the generator running without it shutting down with overheat codes. After digging into the manual and figuring out the process Kix is describing, I was able to add over 1/2 gallon additional coolant and all my problems went away. The key is removing that little panel and extending the fill neck out to where the air can bleed off as the generator runs/heats up. Make sure the overflow tank has coolant in it too, then cap the filler tube and when it cools, it will pull coolant from the overflow tank ...which you likely will have to top off again too.