# Onan 5.5 kW generator maintenance



## rebane (Feb 11, 2012)

My Class A RV is with a gasoline powered Ford engine. It has a gasoline powered 5.5 Onan genset Model HGJAB-901D. It was placed into service middle of 2009 and run-time is at 450 hrs. It runs great. The Operator's Manual recommends "adjust valve lash" and "clean and replace cylinder heads" at this time. These two items increase the maintenance cost from $220 to $1200, e.g. about a thousand dollars. The cost is high because the genset has to be removed from the coach to provide these two service items. Should I plan to incur this added cost every 450 running hours, or can this be delayed until there is some sort of an indication when this service is needed? I do not relish the thought of spending this kind of $$ every 450 running hrs.


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## k2skier (Sep 30, 2008)

Could it have said clean carbon from cylinder heads and replace head gaskets? New heads sounds very odd? Does it run on propane? If it does disregard info, as I know nothing about propane conversions.

I would just adjust the valves if it was mine.


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## Wrench97 (May 10, 2008)

Replacing Cylinder Heads would not be considered "normal" maintenance, nor would removing to clean the carbon. 
Replacing the cylinder head cover gaskets would be part of adjusting the valves, but 450hrs sounds low to me even for that.


If it is a propane conversion that would be less carbon build up.


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## rebane (Feb 11, 2012)

Thanks for the info. The genset runs on regular gasoline from the fuel tank of the RV. I did make a mistake, the manual states: "clean or replace cylinder heads." Thanks for the advice.

rebane


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF

I too would leave the heads alone both in cleaning and replacing. Many, many small engine can run an entire life time with heads never being touched.

Valve adjstents would be nice every year if you can get to them easily.

BG


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## rebane (Feb 11, 2012)

This has been a very good discussion. The statement I quoted is in the maintenance manual that came with the genset, thus your Cummins service advisor is not likely to give you any advice other than "go by the book." 

A good guess on what is going on is a remark by one knowledgeable person. The engine has to comply with EPA emissions rules. It may be that this maintenance is needed to guarantee compliance. I'll go forward assuming that this guess is correct, and will not suffer any pangs of conscience by not spending $1000 for this guarantee. Afterall, I mostly run the genset when overnighting at a truckstop or WalMart parking lot.

:angel: 
rebane


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