Onan generator oil change

[soyjer]

Yes, you are correct...I should have said that he derailed/hijacked "THE" thread instead of "MY" thread, because yes, I did NOT start the thread...I merely replied to an old 2007 post and that was why I mistakenly used the word MY instead of THE.

But my point is that when the topic is "Onan generator oil change", posts in that so-named thread should be solely on the topic of "Onan generator oil change", and people should follow that rule with all posts on all topics, because otherwise it makes searching for information much more difficult...and searching for and sharing information is why I participate in forums such as this.

If you can honestly say that you have never been annoyed by having to wade through numerous off-topic posts in an attempt to find the posts that actually DO address the named thread subject, then "more power to you"...we are just different, that's all. I just would rather spend my time in some other way. For me, off-topic posts are just another form of clutter...similar to SPAM...and clutter just encourages more clutter.

 

[soyjer]

Gary gave an opinion...an educated guess...I think that he would agree with that definition.

I don't come here to make friends...I come here to get answers and share knowledge...which is easier when the information in the thread is on the exact topic that the thread says it's supposed to be. You may disagree.

I believe Gary answered your question on January 10th. Posting a reply like you just did will not make you many friends. All you would have needed to do was post the question again maybe in a different way.    :  Have a nice day. 

 

[HappyWanderer]

This board has very capable moderators. If they feel a topic should be locked or split off, they will.

 

[Rene T]

Gary gave an opinion...an educated guess...I think that he would agree with that definition.
I don't come here to make friends...I come here to get answers and share knowledge...which is easier when the information in the thread is on the exact topic that the thread says it's supposed to be. You may disagree.

You'll find that if you continue on this Forum, when Gary speaks, everyone listens.

I feel sorry for you for not wanting to make friends. I've made a lots of friends here and it's a good feeling to know that I'll probably make many more.
I can see where this is going so I would recommend locking this thread soon.

 

[WILDEBILL308]

You'll find that if you continue on this Forum, when Gary speaks, everyone listens.

I feel sorry for you for not wanting to make friends. I've made a lots of friends here and it's a good feeling to know that I'll probably make many more.
I can see where this is going so I would recommend locking this thread soon.

Sad yes it is sad that people get on hear and are disingenuous when someone gives there opinion on a subject. Someone who (I will bet several cases of cold beverages) has much more experience on the subject. Yet they can't read the owners manual or do a search of the manufacturers web site to get their information.
???
Bill

 

[soyjer]

If this Gary is the same as rvroamer Gary, I have read a LOT of his posts, and concluded that he was an intelligent and knowledgeable guy. I don't think that he would be offended by my comment...I think that he would agree with it. I value his opinion, and it makes sense, but I still was seeking to find out which of the two Onan published torque values was correct.

Regarding my other question about slow oil refilling, I learned today that the problem is that the air above the oil in the oil pan must pass through a tight restriction to reach the valve cover area, and for that reason you must "pump" out the air as you are adding oil in order to be able to quickly refill the oil pan with 1.6 quarts of oil. Fortunately, the breather valve that allows air out of the valve cover area into the atmosphere is a one-way valve, and so you just need to remove the rubber hose from the fitting on the top of the valve cover, then connect a 1/2" I.D. tube connected to a syringe or turkey baster to the fitting on the valve cover, and then pump the syringe or turkey baster to draw air from the oil pan through the "tight restriction" and pass it out the breather valve as you are adding oil to the oil pan. Be careful not to add more than 1.6 quarts, and I'd advise pausing at about 1.3 quarts and maybe turning over the engine before proceeding further, because I'm not sure that the oil pan will hold the full 1.6 quarts without doing so.

I also tried an alternate method of inserting a curved tube into the filler hole until its far end surfaced above the oil level, to see if this "drain" would allow air to escape fast enough to speed up the oil filling process, but it didn't help unless I used a syringe to actively suck air out while filling the oil pan with oil, and that is a lot more trouble and mess than just doing it the above way.

Thank you to all of you who contributed...the posts regarding breather tubes and valves, and hearing other people's experiences, enabled me to figure out how to solve my problem...thanks.    We'll have to agree to disagree about the other thing, I guess.

You'll find that if you continue on this Forum, when Gary speaks, everyone listens.

I feel sorry for you for not wanting to make friends. I've made a lots of friends here and it's a good feeling to know that I'll probably make many more.
I can see where this is going so I would recommend locking this thread soon.

 

[RLSharp]

..... and for that reason you must "pump" out the air as you are adding oil in order to be able to quickly refill the oil pan with 1.6 quarts of oil. Fortunately, the breather valve that allows air out of the valve cover area into the atmosphere is a one-way valve, and so you just need to remove the rubber hose from the fitting on the top of the valve cover, then connect a 1/2" I.D. tube connected to a syringe or turkey baster to the fitting on the valve cover, and then pump the syringe or turkey baster to draw air from the oil pan through the "tight restriction" and pass it out the breather valve as you are adding oil to the oil pan.

This sounds like a two-person job; one to pump out air and one to add oil. Am I understanding this right?

Also, could you post a picture of your vent tube? I just looked at my genset and cannot see anything resembling a vent tube.  Thanks.

R

 

[soyjer]

Down below is my answer to your questions, but I just spoke with an engineer at Onan, and he addressed this issue, and also addressed my question about the contradictory oil drain plug torque value in the owner's manual vs. the service manual.

This is what the engineer said:
When you are filling the oil pan with oil through the oil filling port (dipstick hole), and have reached the point where the crankcase air can no longer escape out the filling port without having to bubble up though the oil, the only other route for the crankcase air to escape into the atmosphere is PAST THE PISTON RINGS, and THEN either out through an OPEN intake or exhaust valve, or very slowly leak past the CLOSED valves.

My pumping method works, but after hearing the above, I now totally don't understand why. All I'm doing is pumping air from inside of the valve cover out the breather (reed) valve to the atmosphere, and SOMEHOW this applies suction to and draws air out of the crankcase. My mind is telling me that there MUST be some other path that is being used (other than the piston ring path), but I didn't want to take up any more of the engineer's time, so it remains a mystery to me...it just works, that's all I know.

Sooooo...if the oil flows slowly when filling, you can either bump the starter without starting the engine somehow (to open an intake/exhaust valve) and see if that helps, or you can use my "pump" method (clarification is down below).

Regarding the oil pan drain plug (above the little cover on the bottom of the oil pan) The engineer couldn't explain why the Owner's manuals all seem to say "21 lbs-ft" and the Service manuals (I was able to check both the '97 and '06 Service manuals) say "5-8 lbs-ft".  He recommended the 5-8 lbs-ft and using an oil-proof paste teflon sealant on the threads (not teflon tape). He didn't know why the Owner's manuals specified 21 lbs-ft. All I know for sure is that the plug is brass and is listed as a 1/4" NPT tapered brass plug, and it is screwing into an aluminum oil pan...and, to me, 21 lbs-ft seems high. However, before I talked to the engineer, I installed mine using 14 lbs-ft (with no sealant), without running the engine afterward, and it leaked a drop or two out of the plug hole overnight. I re-tightened it to about 17 lbs-ft...will see tomorrow if that stops the leak. I'm not a plumber nor an auto mechanic...maybe 21 lbs-ft for tightening a 1/4" NPT brass DRY plug into aluminum is OK...it just didn't feel right to me, that's all. Next oil change I'll follow the engineer's advice and use the 5-8 lbs-ft and an oil-proof paste teflon sealant on the threads (not teflon tape).

Below is the breather tube clarification
--------------------------------------------------------------------------------
My generator is an Onan MicroQuiet 4000 series 4KY Spec: K (4KYFA26100K), but likely this applies to most/all 4000 series generators:

The Breather Tube (aka vent tube or hose) #123-1917 comes out of the top of the Valve Cover #110-3743 and extends about 7" to the left and back over to the air intake chamber (where the air filter is). You could verify that it is the correct tube by blowing on the end that you disconnect, and see if the air comes out of the hole in the air intake chamber.

The Breather Valve #123-1920 is inside the Valve Cover so you cannot see it at all. The fact that it is a one-way (reed) valve enables you to pump air out of the crankcase using just one connection and one hand. One hand could operate the syringe while the other pours the oil.

This sounds like a two-person job; one to pump out air and one to add oil. Am I understanding this right?

Also, could you post a picture of your vent tube? I just looked at my genset and cannot see anything resembling a vent tube.  Thanks.

R

 

[driftless shifter]

NPT is tapered, I'd be real careful about much more torque on it. May split aluminum cast. I'm an air-cooled VW geek, VW's of that era used mag, aluminum alloy castings for the crankcase. Many an over enthusiastic rookie has cracked their case by over tightening their oil sender.

Bill

 

[Ken & Sheila]

The Onan Service Manual for the Microlite 4000 KY series call for 5-8.
http://www.cumminsonan.com/www/pdf/manuals/981-0503.pdf

Sec 4, pg 1

 

[WILDEBILL308]

NPT is tapered, I'd be real careful about much more torque on it. May split aluminum cast. I'm an air-cooled VW geek, VW's of that era used mag, aluminum alloy castings for the crankcase. Many an over enthusiastic rookie has cracked their case by over tightening their oil sender.

Bill

You are right Bill. I was thinking 8-10. lbs ft would be a lot of torque,so 5-8 with a thread sealer is the way to go. 21 lbs ft would make money for Onan doing repairs.
Bill

 

[RLSharp]

My generator is an Onan MicroQuiet 4000 series 4KY Spec: K (4KYFA26100K), .....

That explains why I can't find a breather tube on mine, it is an Onan 5.5K.

Also, my drain system uses a petcock type valve to drain the oil, so I do not have to worry about torque specs.

Thanks for the detailed description.

R

 

[soyjer]

Yes, as I stated above, the SERVICE manuals that I checked ('97 and '06) both said 5-8 lbs-ft. It's the OWNER'S manuals that state 21 lbs-ft. Like I said the Onan engineer couldn't explain it, nor why no one seems to have noticed it but me over the past decade+. Perhaps the service people never look at the owner's manual and owners typically don't read the service manual?

The Onan Service Manual for the Microlite 4000 KY series call for 5-8.
http://www.cumminsonan.com/www/pdf/manuals/981-0503.pdf

Sec 4, pg 1

 

[soyjer]

You are right Bill. I was thinking 8-10. lbs ft would be a lot of torque,so 5-8 with a thread sealer is the way to go. 21 lbs ft would make money for Onan doing repairs.
Bill

Checked my drain plug again today...even 17 lbs-ft didn't stop the very slight leaking (drop on bottom of plug and small stain on asphalt below), so I drained out the brand new oil and took a look up the drain hole with a flashlight...it's worse than I'd thought...the engineer who recommended using Teflon paste failed to mention that there are only 3 threads on the oil pan drain hole that actually go 360 degrees around the hole without interruption...the top 2/3 the hole has "cut-outs" 180 degrees apart, and so if you put Teflon paste on the upper 2/3 of the plug, that paste would end up in the oil pan. I'm assuming that the reason for the "cut-outs" is because, instead of just having the drain hole BELOW the bottom of the oil pan (which would seem to make more sense), for some reason on this oil pan they designed it with 2/3 of the threads ABOVE the bottom of the oil pan. Not only does this make using a sealant on the top 2/3 of the threads probably unwise, it also severely weakens the drain hole such that the tapered 1/4 NPT -14 drain plug could easily force the two halves of the upper 2/3 of the drain hole apart, such that only the bottom 3 threads of the drain hole are actually holding tightly onto the drain plug.

The bottom of the oil pan around the drain hole has a flat round surface about 1/8" wide, so I'm hoping that I can find either a thin metal washer and a gasket for the existing drain plug, or a new 1/4 NPT -14 drain plug that includes a metal flange and gasket. Starting with the SPEC L engines (mine is a SPEC K), a different drain plug WITH GASKET is used, even though the oil pan part number is unchanged, so maybe Onan came up with a better drain plug for the 4000 series starting with SPEC K.

As I mentioned in a previous post, the Onan engineer didn't know why the Operator's manuals say 21 lbs-ft and the Service manuals (I checked '97 and '06) say 5-8 lbs-ft, and he didn't seem concerned about it, either. But if 5-8 lbs-ft is the correct torque value, then...considering the weak design of the drain hole and the fact that it is an aluminum oil pan...21 lbs-ft would seem to be so high that it would be prone to damaging the drain hole. Now that I know the weakness of the drain hole design, I'm going to try to call Onan headquarters and see if I can find someone who can explain the contradictory published torque values and see if the newer drain plug can be used in the older oil pans. I'm still puzzled as to how the contradictory torque values could have been out there for apparently over a decade without anyone correcting the manuals or notifying customers, dealers, and service centers about them.

 

[Gary RV_Wizard]

Auto parts stores have gaskets for oil drain plugs - they get lost or damaged all the time. Metal, fiber, nylon or rubber are available. Here are a few:
http://www.autozone.com/test-scan-and-specialty-tools/oil-drain-plug-gasket.

 

[Rene T]

Gary, I think those gaskets are designed for plugs with a sealing flange next to the head and the plugs are also straight threads I believe. The plugs we're talking about have tapered threads. The plug would have to have a flange near the top to receive the gasket and provide a sealing surface. I don't know if plugs like that are available. I've never seen one. I suppose one could be made if you had a access to a machine lathe.  Or you could go with something like this. http://www.summitracing.com/parts/omx-1747013?seid=srese1&gclid=CKOu2OTuncMCFVg8gQodh3kAZA  If you could get the threads to seal, you'd never have to worry about it again.
 
The other option would be to drill out the tapered threads and tap the hole with straight threads. That would be dangerous as far as getting metal chips in the crankcase.

 

[Gary RV_Wizard]

Tapered threads (if that's what he has) are probably pipe thread, either National Course or National Fine thread. A flanged plug should not be hard to find if needed.

But if I remember correctly, my Onan genset has a typical flanged oil plug. That's a 7500 QD model, though.

 

[Rene T]

it also severely weakens the drain hole such that the tapered 1/4 NPT -14 drain plug could easily force the two halves of the upper 2/3 of the drain hole apart, such that only the bottom 3 threads of the drain hole are actually holding tightly onto the drain plug

This is the reason I said tapered threads which is a pipe thread. Finding a plug for this would be hard to find with a flange because you would want the flange to make contact with the gasket at the same time you ended up with 100% thread engagement.

 

[driftless shifter]

Checked my drain plug again today...even 17 lbs-ft didn't stop the very slight leaking (drop on bottom of plug and small stain on asphalt below), so I drained out the brand new oil and took a look up the drain hole with a flashlight...it's worse than I'd thought...the engineer who recommended using Teflon paste failed to mention that there are only 3 threads on the oil pan drain hole that actually go 360 degrees around the hole without interruption...the top 2/3 the hole has "cut-outs" 180 degrees apart, and so if you put Teflon paste on the upper 2/3 of the plug, that paste would end up in the oil pan. I'm assuming that the reason for the "cut-outs" is because, instead of just having the drain hole BELOW the bottom of the oil pan (which would seem to make more sense), for some reason on this oil pan they designed it with 2/3 of the threads ABOVE the bottom of the oil pan. Not only does this make using a sealant on the top 2/3 of the threads probably unwise, it also severely weakens the drain hole such that the tapered 1/4 NPT -14 drain plug could easily force the two halves of the upper 2/3 of the drain hole apart, such that only the bottom 3 threads of the drain hole are actually holding tightly onto the drain plug.

The bottom of the oil pan around the drain hole has a flat round surface about 1/8" wide, so I'm hoping that I can find either a thin metal washer and a gasket for the existing drain plug, or a new 1/4 NPT -14 drain plug that includes a metal flange and gasket. Starting with the SPEC L engines (mine is a SPEC K), a different drain plug WITH GASKET is used, even though the oil pan part number is unchanged, so maybe Onan came up with a better drain plug for the 4000 series starting with SPEC K.

As I mentioned in a previous post, the Onan engineer didn't know why the Operator's manuals say 21 lbs-ft and the Service manuals (I checked '97 and '06) say 5-8 lbs-ft, and he didn't seem concerned about it, either. But if 5-8 lbs-ft is the correct torque value, then...considering the weak design of the drain hole and the fact that it is an aluminum oil pan...21 lbs-ft would seem to be so high that it would be prone to damaging the drain hole. Now that I know the weakness of the drain hole design, I'm going to try to call Onan headquarters and see if I can find someone who can explain the contradictory published torque values and see if the newer drain plug can be used in the older oil pans. I'm still puzzled as to how the contradictory torque values could have been out there for apparently over a decade without anyone correcting the manuals or notifying customers, dealers, and service centers about them.

I'd be concerned these cut outs you speak of weren't actually cracked aluminum casting. There is a jerry rig fix using high quality epoxy and a pipe nipple with a new drain plug at the end of the nipple..

Bill

 

[Gary RV_Wizard]

This is the reason I said tapered threads which is a pipe thread. Finding a plug for this would be hard to find with a flange because you would want the flange to make contact with the gasket at the same time you ended up with 100% thread engagement.

Yeah, you would want a fat, soft gasket with that set-up, so that it fills the gap as you could compress the gasket.

Here is a brass plug with enough flange to seat a washer/gasket. Don't need much since its an almost zero pressure application.
http://www.zoro.com/i/G5123176/?category=5764

Or get somebody to weld a flange on a standard pipe plug.  8)