So in our 27-year-old Winnebago Warrior, we have a Suburban NT30KLT furnace.In the last couple of years, the first time it fires up you can hear the fan bearing squalling a bit and then it quiets down. I'm sure it needs some oil. Presumably they use oil-impregnated bronze bushings in the motor assembly and I'm sure they have just dried out over the years.I pulled the access hatch, but all you can see is the burner chambers. The squirrel cage fan is behind the heater box, and there is no access to it.It appears the outside exhaust and intake frames screw into the side of the camper and hold the tubes tight on the furnace on the back end. I can't see anything that secures it from the front. Does it just pull out? Looks like I'd have to disconnect the gas line and the ductwork which is not going to be easy.Any ideas?Steve

On our trip in 2011 we were having the same problem and in Hill City with the temp hovering about 2i degrees, at about 02:00am, the darn thing woke half the campground with it's scream. Had I oiled the bearings earlier it would likely been good for a year or two more but eventually it is going to die at the most inconvenient time, so my recommendation is get a new motor or a new heater.It is a pain but you can find a new motor, they do exist. Contact Lichtsinn in Iowa and ask.No matter what you do, oil or replace, you will have to pull the heater. Exhaust intake tubes off, cabinet torn apart it is a royal pain. Then you have to get the squirrel cage off, be very careful, there are tools for doing it but harder to find than the motor, so if you can get a motor with the fan attached, DO IT.Have fun and good luck.

First, the fan has BUSHINGS, not bearings.And in many cases, they can be lubed in place. You need light-viscosity oil such as sewing machine oil in a dispenser with LONG tip.Place a few drops on the shaft right next to the motor. Repeat a couple of times-- the oil will "wick in".Note: This IS true for the Atwood furnace, suspect also applies to other brands.

I don't think they have bearings - some have had luck with squirting oil. I have had some luck eliminating squeaks with various automobile fans by running them for an hour or so. I rarely use the heater in my 92 and when I started to get squeak I let the heater run for an hour ... that was 3 years ago and haven't heard a squeak since. I didn't think there was much downside - if my MacGyver didn't work then I was prepared to replace the motor. Worth a shot.

Really amazing -Small ball bearings are not at all expensive. The motor case would cost more to manufacture but with a decent non Chinese bearing, a small motor bearing would last one hundred years.The soy-sauce sintered-bronze (If you think oil-lite quality bushing, you dream) bushings in today's junk does not respond well to lubing. Me and an expensive Harbor Freight (Well, it cost EIGHTY dollars!) rotary squirrel cage fan had a toe-to-toe knock down drag out fight about ten years ago. I was determined to ventilate a four room house and it was determined to commit seppuku. The fan had a few thousand hours of use. But what the heck it was a matter of lubrication.The fan upon startup began to make neighborhood dogs howl.I substituted a pair of Fantastic Endless breeze fans and went to work.Off came the squirrel cage and out came the fan motor. The Chinese thought it essential to demand use of a foot long tiny mm set screw allen wrench to get to the screw - don't ask.Out popped the armature. I spent a half-hour examining its windings to make sure I wasn't flogging a dead horse. All OK in the copper dept.The armature shaft was not shiny chrome looking. The school of hard knocks later showed that the "staining" was actually smeared bushing material but at the time I use fingers to determine the shaft was good to go as far as no grooves, taper or roughness.The bushing under a strong light, after alcohol, Q-tips and patience was used to clean out the interior of the knob-line sheet metal protrudence revealed the same smearing glaze that I saw on the armature shaft. Nothing to do but rub harder. I used brake cleaner but that did not remove the glaze. The Q-tips after rubbing came out shiny.Now it was time to lube. Being neurotic, I do not inventory just any oil, no, it has to be the "best" for sintered bushingsWait a minute! Wait a minute! I am not going to go through this again!I held the housing up high and drilled a 1/16" hole from the bottom up right in the center of the bushing knob.Then spent even more time flushing and cleaning out the inside of the "bore". I found only couple of good size chip residue with the Q-tipsThen, I plastered a piece of oil proof adhesive patch on the outside of the sheet metal. Let it dry overnight.Then used an absurd amount of oil to fill the hole.Placed the armature shaft into the bushing bore and spent the next hour reassembling the fan.Plugged it in, tapped the rocker switch and TAH-DH, noise gone. Silent and powerful blast of air.Two weeks later I woke up in the middle of the night to a squealing fan. This time I smelled hot electrical.WHY!Back apart it went. Got to the bushing and shaft. The staining on the shaft was worse. Same with the shaft only this time the shaft did not feel mirror smooth.That oil I used was lab grade turbine oil. And there ain't no better lube for a slow speed bushing.MORAL OF THE STORYNever Again!PS: I was a hundred miles from the nearest store that sold larger fans. Harbor Freight? Make a left and don't take your foot off the gas for a thousand miles.PPS: Your mileage may vary

As previously noted, the fan has bushings not roller or ball bearings. The squeal is because of bushing and shaft wear. Lubrication will only cause the squeal to go away for a short period of time. The motor needs to be replaced.Richard

How to lubricate fan bearings in furnace? | Good Sam Community

maillemaker
Explorer
Mar 26, 2018
For future readers, the motor is here:

https://www.makariosrv.com/suburban-furnace-motor-521137/

If I could get the fans off the shafts, I'd replace the motor.

Steve
maillemaker
Explorer
Mar 26, 2018
There was some rust on the burner assemblies, but not anything in the motor housing that I could see.

I ended up squirting light oil (RemOil) onto the end of the shaft. Since the shaft had a flat spot ground on it for the set screw, the oil could go down the flat spot, through the fan cage, and, hopefully, down to the bearing. I did this for both ends of the motor (both fans).

Put it all back together, and there is no squeal on running now. I don't know how much oil I was able to deliver to the bearing, so I don't know how long the fix will last.

I should have tried setting a socket on the fan cage hub and giving it some light taps after letting the oil soak in.

Steve
trailrider
Explorer
Mar 26, 2018
Not pressed on. Rust!
maillemaker
Explorer
Mar 25, 2018
I got the furnace out this weekend. I have the blower assembly disconnected from the rest of the furnace, but I cannot remove the cage fans from the motor shafts. I was able to break loose the set screw on the smaller fan, but not on the larger fan. And even when the set screw was loosened, the fan would not come off the shaft. Is it pressed on?

Steve
Chum_lee
Explorer
Oct 10, 2017
I like Tri-Flow bike chain lubricant. It comes in an aerosol can with a fine straw spray nozzle. It works great for Kwikee steps too.

Chum lee
maillemaker
Explorer
Oct 10, 2017
Couple of post prior I gave you a clicky to the zoom spout oiler. What you can't tell is that the thing pulls out about 12 inches and can get into just about any tight space.

The problem is that I cannot see the fan. When I pulled the metal covers off of the intake and exhaust I could barely make out the cage of the fan, but can't get any access to the fan motor bearings.

BTW, don't get snippy with posters. If you knew everything you wouldn't be asking these dumb questions.

I just get annoyed when I ask "how do you access the motor in the furnace" and a third of the responses want to debate the proper word for a bearing and another guy wants to go off on some tangent about Harbor Freight.

We have a Suburban furnace and it's one of the ones with only the little plate with the Intake and Exhaust tubes on the outside. I'd much rather have the version with the large full cover that lets you do more "work on the furnace" labor from outside.

That's what I've got.

So the answer to all of this is: "You've got to pull the furnace assembly to get access to the blower motor".

Steve
j-d
Explorer II
Oct 10, 2017
Steve, I can't tell you how to access that furnace motor. You've got the manual, just follow it. We have a Suburban furnace and it's one of the ones with only the little plate with the Intake and Exhaust tubes on the outside. I'd much rather have the version with the large full cover that lets you do more "work on the furnace" labor from outside.
That "Zoom Spout Oiler" is my GoTo, but just about everything has limitations. If you can get in there, by all means Zoom Oil it. Odds are very good it'll be quiet again for years. But like Mex mentions, things have limitations. A blower motor from our Coleman Mach rooftop A/C sits in my garage in testimony to that. One day camping at the beach, NO A/C. Blower motor isn't turning. No problem I've got a Zoom Oiler. Apply Oil and at Runs. Next day, stuck again. Oil again. Repeat the Stuck and Oil, Oil and Stuck routine. Took it home, completely dismantled the motor. Cleaned and polished Shaft, Bearings (Sleeve/Oilite/Bushing/Whatever), Oiled and Assembled. Good to Go? ***NOT*** I ran a bench test with Motor running on a Power Supply, Squirrel Cage Mounted... and it STUCK. The "bushings" don't seem to be a "bronze" material, more of a "steel." I can only figure the "steel" is porous and it's contaminated with something that turns Oil to Glue.
I'd actually drilled the rivets out of the bearing retainers to remove, soak, clean, and oil the bushings. Put it all together, installed it, and Ordered a New Motor. Had it shipped to our next campground and installed it there, replacing the one that was already stuck again.
So Steve, if you can ever get access to the thing, I'll give you 75% that Zoom Oil will cure it. But no more than that. Consider the value of your time. People tell me that all the time, and I still waste a lot of time.
But ABOVE ALL, this is a Furnace. Be sure nothing is rusted through, it all fits together right, you can get correct gasket wherever needed and so on!
MEXICOWANDERER
Explorer
Oct 10, 2017
**** I tried balancing a 45 lb Oxford dictionary on my lap and failed. Better to avoid the Syntax Police...

Oilite Bushings. I promise in the morning to reach for the phone and gave them the bad news. Gettin' right on it.
time2roll
Nomad
Oct 09, 2017
To reach in with a half drop of lubricant I use a clock oiler.

https://www.amazon.com/Creative-Clock-Oil-Kit/dp/B0089SKKY6
Boon_Docker
Explorer III
Oct 09, 2017
OUCH !

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