Air Cleaner Removal Quiet Diesel 10KW Generator

[Mike Groves]

While doing maintenance on my 10KW generator, I began to take the air cleaner out, but feared I'd have trouble getting the new back into it, so I didn't change it out.  Generator has been running great and according to a service record from just before I bought it, a new filter had been put in.  So no worries I guess, but at some point I'd like to change the air filter.

Any tips and tricks for getting this out or is it simply trial and error and tough to do.  Many owners of 1998-2001 Marquis coaches have this same generator I believe so perhaps someone here has experienced this issue.

Thanks,
Mike

[Gerald Farris]

Mike,
It is just a little tight, but it is doable. How long has it been since the belt was changed on your generator? The belt should be changed around every 1,000 hours, and if you are changing the belt, the air filter is very easy to change because the enclosure cabinet top has to be removed to change the belt.

Gerald   

[Mike Groves]

Thanks Gerald,

I would suspect the belt has never been changed.  The generator has less than 700 hours on it (its over in storage but this answer is based on it having 640 hrs when I did its oil/antifreeze change out on 7/19/2014, and running it a couple hours per month since then.

The belt would probably be most affected by dry rot over the years since being installed in August 1998 for the 1999 model year.  Then again, its been resold by Guaranty RV in 2004, so perhaps they reconditioned it?

The generator runs very well, and there is lots of wind being created by the belt driven fan.  The only problems I had was during the oil change when low pressure locked me out.  I simply turned the chassis batteries off, then on again, and restarted and the pressure was ok then.  To cut down on the types of antifreeze to carry, I've filled it with OAT antifreeze - same as the engine.  I've not had a high temperature shutdown so I guess the thermostat is still good.

Since storing it, I've run the generator for 2 hours every 3-4 weeks while in storage.  We've not used it much during travel since my initial cross country trip during April to June of 2014.

Doesn't appear to be much room in under there to get the top off.  I suppose you'd put the slide out, and then get back in there, but still doesn't seem to be much room.  That operation might just have to be undertaken by Onan.

Mike

[Fred Brooks]

     Mike,

 Believe it or not, but it is on my list of things to do.  Just haven't done it. Seems like Gerald has a wealth of experiance about these coaches and well worth listening to. I did change the air filter and he is right, a knucle buster if you go too fast. I did inquire about the belt at my local Onan dealer. He said between certain serial numbers on the 10K the pulley size was changed. Of coarse my Gen is just like yours and I was not in the mood to crawl in there and take stuff apart. Let me know how yours turns out. I'm on a Rally headed for Santa Barbara then Hearst Castle. Hope my Gen holds up with 775 hours on it.
      Regards, Fred

[Dick Simonis]

Gerald is sure spot on regarding the belt.

When I bought the Marquis last year it had just over 1,000 hours and suddenly it started shutting down on overheat.  After a bit of troubleshooting, yep, slipping fan belt and I decided way beyond my ability to service.  Ended up taking it to Premier Motor Coach for service and had them do a complete service including changing the temp sensor...another potential failure item.  They pulled it, did all the works and had it back in the same day.  Worth the $$$ to have a professional do the job.

The only hiccup was that the tech overtighened the oil cooler drain plug and they had to replace the cooler but that's another story.  Still they did great work and stepped up to the plate on the cooler.

[Edward Buker]

The air cleaner housing is bolted through the top cover and comes down with 4 bolts. If need be you can loosen or remove them to adjust position which may make it a bit easier.

Regarding the belt change....

You do not need to remove the top cover. You need to unbolt the air cleaner housing and the coolant overflow tank to release them from the top cover, they just rest inside. Then remove the bolts holding the top cover down, and the right L shaped end plate, then lift the top plate enough to release the end cover and pull it out. The top cover sets back down on the back cover and frame while you work. I would not try and do this job without a Gear Wrench 10mm wrench with the ratcheting end on it...invaluable to reach and remove these cover screws that are on the top back or behind frame members that support the genset.

A little more info on the 10KW Genset with the Isuzu diesel. The info in the service bulletins about SN vs belt used is not correct. My serial number is well beyond the end date for the 10.75MM wide belt and should have had the 13.3MM wide belt but it does not. If you plan on doing this job you will have to measure the top pulley width outside dimension and if it is 5/8' wide you use the 511-210 belt, if wider then the 511-212 belt. Cummins says SN J99 and older uses a 511-210. For G01 and newer it uses a 511-212. In between is anybody's guess. The letter is the month and two digits for the year. G01 is July 01 but my SN begins with K01 which is Nov 01 and I still had the narrow belt. So be prepared to sort this out once the set is apart.

Regarding belt quality and your genset design.... The worst design for belt load and life is the narrow belt with the alternator option. I believe adding the alternator created most of the issue which caused the change to a 13.3mm belt. Gerald gets 500hrs out of a belt but has an idler pulley. I got about 58 hours out of my last belt with the alternator option. I have requested Cummins engineering look at this issue and that will probably not yield anything helpful but good that they know. I told them that the Bando Power Flex E belt, which is what they are still stocking for the 511-210 PN that they sold me, did not last 50 hours and I assured them that it was very well tensioned anticipating some stretch and that my pulley surfaces were clean. My conclusion is that these belts are incompatible with the loads of the application which is probably why the redesign of the pulley system occurred in the first place. I also passed along this info from some other forum folks regarding this issue and told them that the problem is systemic to the design...

"Mine has the Isuzu engine (5231 hrs) and only uses one belt. $500 labor to have it changed by a Cummings/Onan dealer. Needless to say, we learned how to change them ourselves very quickly! The crew I travel with have 3 coaches with the 12.5 Onan/Isuzu... great generator, terrible design on the pump, fan, alt. belt. Sometimes we would get only 100 hours before the belt would start slipping, get a overheat code, and the generator would shut down. You could tighten the belt and get a few more hours out of it, but it was still a major pain. We've tried every belt and brand out there over the years, and the only one we've had any luck with is the NAPA 7320 XL. Our record for this belt is 2000 hrs....quite an improvement from the earlier ones."

By that post it would seem that everyone with the 10K or 12k Isuzu Diesel gensets with alternators for sure have the issue.... I have gone ahead and installed the NAPA 7320XL belt which by appearance looks more robust then the Bando OEM belt. You need to tension this belt very well. The deflection spec is .3 to .4 inches with 22lbs of force midway between the alternator and pump pulley which is quite tight. NAPA sells an inexpensive Vbelt tension clicking type gauge that works quite well if you feel you need one.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Belt-Tension-Gauge/_/R-NBGKR1_0006447252

The best way I found to get proper tension adjustment is to cut a small block of wood and place it against the alternator pulley and use a small screw bar clamp between the pulley block and the slotted end of the alternator arm to adjust it and then tighten the bolts down. I ran the genset several minutes and then tensioned it again. There is no cooling air without the cover and blower on so keep the run time short.

I had a Cummins lead tech tell me to remove the wires from the alternator to eliminate a good portion of the belt load which if I have trouble again will be my next step. This job I can now do in about 3 to 4 hours, not fun, but it went much easier the second time around. Photos of blower housing, blower, belt and alternator arrangement,  pulley measurement, and bar clamp belt tension set up. Sorry this got so long, just a lot to it...Hope this helps.

Later Ed

[Mike Groves]

Thanks Ed,

I think I've learned a lot, but also I'm generating some more questions.  As I've said, I am not concerned yet about my belt, but you've explained the filter issue and I think I get that.

Regarding the belt however, I've now learned that its on the right side of the unit rather than on the left as, for some reason I'd assumed, so I've got that now.

I looked up "Gearwrench" and they seem to come in all types, so I'd assumed it was the one sort of like a normal boxed in wrench but with gears so you can ratchet that if you slip it over the top of the generator, laying it flat on a bolt on top and you can ratchet it back and forth in the same plane as the top of the generator.  Do you know what I mean, and is that correct?

I suppose I need to get to my generator book and see these panels, to see that slightly lifting the top panel to the right side will allow the side panel to come out.  But that's what I am reading in your post.  I hope I got that right.

Eventually I guess I'll have to do this - probably the first time I get a high temp warning and I shut down - followed by a startup without all the air that I am currently getting, so it will be pretty easy to diagnose.

Wow, after doing it again and again its still taking 4 hours, that's not sounding hopeful, but I would rather do it on my time vs Cummins'.

Thanks VERY NICE INFORMATION!  Especially about the filter bolts.  Now I just need a picture of your 10mm gearwrench so that I know what to get.

Thanks again Ed,
Mike

[Edward Buker]

Mike,

I just posted a bit more information and a PN belt correction, with a modify so you may want to read the post again.

You do this job between the slide and the genset and I turn the battery switches off, and remove 120V, to be sure the slide cannot be moved. The top cover holds the right/front L shaped cover captive until you lift the top enough to release it. Once you lift it enough, the L shape panel is worked out the front. From there you have access to the blower cover, then the centrifugal blower, then the blower bulkhead which all unbolt to give you access.

The gear wrench is a standard open and box wrench where the box end has a fine ratchet built in. It is the tool that gives the shortest most sure reach to the top cover bolts on the back and also access to the bolts that are behind frame supports, where there might be only be one inch of clearance between the frame and the bolt. I also got this tip from Gerald, I sprayed all the cover bolts with light oil and was able to start them and work them most of the way in by hand before having to start with the ratchet. About half the bolts are easy access, and half are at arms length or behind some obstruction. It is not that hard to do if you have "played" over the years.....perhaps a 6 swear and one rapped knuckle job :-)

Later Ed