Generators and Electric Motors
[Home] - [HELP] - [Forums] - [Groups] - [Classified Ads] - [Subscribe] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Onan Generators
Forgot Password? Join Us!

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators. When asking new questions about your generator, ALWAYS give your model number AND serial number.

Onan Generators

Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush


this thread has 5 replies and has been viewed 7113 times

Reply
 
Thread Tools Display Modes
  #1  
Old 11-06-2010, 11:20:22 PM
BCS BCS is offline
Registered
 
Join Date: Nov 2010
Location: Fair Lawn, New Jersey
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

I recently purchased a preowned enclosed gooseneck trailer with an Onan CMQD 10000 series generator. Exact model is 10HDKCC-A

I just completed servicing it with a coolant flush, oil, air filter and fuel filter change.

Long story short, after the coolant flush, the generator ran for about 5 minutes and then shut off with the Hi Temp error code. I came across some information that there's an airlock which prevents coolant from circulating through the radiator, etc. and causes overheating. I did not use a funnel the first time and apparently if one is not used when filling the radiator, it's possible for coolant to go into the vent hose and create an air bubble that will prevent proper circulation of coolant...thus overheating.

So, I re-flushed the system, cleared the hoses to remove all the coolant and used a long funnel (approx 3 inches below the vent hose) and filled with approximately 3/4 gallon of coolant (peak 50/50...no water needed). I then started up the generator with the coolant pressure cap off to let any air bubbles come out, etc. Afterwards, I put the cap back on (new cap) and started the generator and it ran beautifully for about an hour. I shut it off and thought nothing of it.

Today (3 days later), I filled up the overflow tank to the cold level and fired up the generator. About 7 minutes later, the generator shut down with the same high temp fault code. I assumed it had to do with filling the overflow tank so I decided to re-flush the system again.

This time when I ran the engine with the coolant cap off, everything was fine for the first minute or so and then the coolant started to rise in the fill tube until it was overflowing all over the place and so I shut off the engine.

The generator ran without any issues prior to the coolant flush so I am assuming it has to do with that? Perhaps something else is causing this problem, but there's plenty of air coming from the bottom front of the generator (away from the radiator) so I dont think it's the belt... perhaps it's the thermostat? How would I know if the thermostat is the culprit?

Any other suggestions before I have to take it in to a qualified service center? I really hope this is something I can figure out on my own as I was quoted 350.00 for just an air filter and oil change. That i did on my own for 15 minutes and for a fraction of the price!

Thanks.
Reply With Quote
Sponsored Links
  #2  
Old 11-07-2010, 11:12:42 AM
cornbinder89 cornbinder89 is offline
Registered
 
Join Date: Feb 2010
Location: Lyman, Iowa
Posts: 949
Thanks: 69
Thanked 552 Times in 358 Posts
Default Re: Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

Well I wonder how you "flushed" the cooling system without pulling the thermostat? Quite possable you dis-lodged some rust and scale and it is now plugging the radiator.
Start by pulling the thermostat and testing. With the thermostat out, fill and run with the cap off and look at the flow thru the radiator. Check for cool spot in the rad which would indicate some plugged tubes.
If in doubt pull the radiator and take it somewhere to have it cleaned.
Reply With Quote
  #3  
Old 11-07-2010, 09:36:04 PM
BCS BCS is offline
Registered
 
Join Date: Nov 2010
Location: Fair Lawn, New Jersey
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

Quote:
Originally Posted by cornbinder89 View Post
Well I wonder how you "flushed" the cooling system without pulling the thermostat? Quite possable you dis-lodged some rust and scale and it is now plugging the radiator.
Start by pulling the thermostat and testing. With the thermostat out, fill and run with the cap off and look at the flow thru the radiator. Check for cool spot in the rad which would indicate some plugged tubes.
If in doubt pull the radiator and take it somewhere to have it cleaned.
You read my mind. I was going to ask about the thermostat. I did not pull it and check. I assume that could be the issue. Is the thermostat accessible through the access door? The generator is enclosed in the trailer and the only access I have without taking all the panels off is this opening.
Reply With Quote
  #4  
Old 11-07-2010, 10:35:16 PM
mrmegoo mrmegoo is offline
Registered
 
Join Date: Aug 2009
Location: S.E. Missouri
Posts: 516
Thanks: 336
Thanked 362 Times in 233 Posts
Default Re: Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

BCS, The radiator cap is attached to a long hose & you should pull it up & out of the access hole. Refill the coolant while holding it up as high as possible. Install the cap & run it for approx 5 min & then recheck & add additional coolant as needed, repeat several times. I have had this scenario in the shop several times. Section 3 pg 7 in the manual. Manual can be downloaded from the following address.
http://www.cumminsonan.com/www/pdf/manuals/
Manual for your unit is # 980-0540B
Mel
Reply With Quote
  #5  
Old 11-08-2010, 09:52:22 AM
mrmegoo mrmegoo is offline
Registered
 
Join Date: Aug 2009
Location: S.E. Missouri
Posts: 516
Thanks: 336
Thanked 362 Times in 233 Posts
Default Re: Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

BCS, one more bit of information. You stated in the first post you refilled the radiator with 3/4 gallon of coolant. The capacity of the cooling system is 6.6 quarts or just over 1-1/2 gallon.
Mel
Reply With Quote
  #6  
Old 11-08-2010, 11:36:06 AM
BCS BCS is offline
Registered
 
Join Date: Nov 2010
Location: Fair Lawn, New Jersey
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: Commercial Series Quiet Diesel 10000 Overheating after Coolant Flush

Quote:
Originally Posted by mrmegoo View Post
BCS, The radiator cap is attached to a long hose & you should pull it up & out of the access hole. Refill the coolant while holding it up as high as possible. Install the cap & run it for approx 5 min & then recheck & add additional coolant as needed, repeat several times. I have had this scenario in the shop several times. Section 3 pg 7 in the manual. Manual can be downloaded from the following address.
http://www.cumminsonan.com/www/pdf/manuals/
Manual for your unit is # 980-0540B
Mel
Mel,

That's exactly what I did. I filled it up while the fill tube was out and high as possible. I would say it was approximately 4 inches above the top of the generator when I filled it up. I filled it with a little more than 3/4 of a gallon b/c that's all that would go in without it overflowing out of the fill tube.

Something is definitely blocking the coolant...whether it's an air bubble, which I cant get out (drained and flushed per manual approximately 4 times now) or a broken thermostat (which still wouldnt explain why no more than a gallon of coolant can be poured in) or debris blocking the radiator, etc. Im not sure what's going on here.

When I drained the coolant out the first time, there was definitely about 1 1/2 gallons of coolant in there and now I can barely get a gallon in there without it overflowing out the fill tube.

Unfortunately, the generator is in the front end of the gooseneck trailer with no slide out so unless I can some how pull the panels off, Im limited to the maintenance access door and possibly the top small square panel.
Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Advice for 10k Quiet Diesel dilemma FlyAwes Onan Generators 6 03-23-2010 11:42:41 AM
6.5 KW ONAN MCCK Overheating Low on coolant Major Tom Onan Generators 6 05-26-2009 04:18:44 PM
Onan Quiet Diesel Question jas67 Onan Generators 9 05-04-2009 05:27:53 PM
Kohler 60RHOZ81 Turbo Diesel with coolant in oil Nazrat Kohler Generators 24 04-08-2009 09:19:52 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 04:44:20 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2019 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277