Stihl 024 AV leaks bar oil

root66

This saw has served me well for almost 22 years. It gets only occasional use. I've had a problem from day one that I should have had addressed way back when. The saw leaks bar oil when stored. It will drain the tank if it sits long enough.

There are no cracks in the tank or anything of that sort.

I've taken the saw apart and have ordered a new oil pickup hose thinking the leak may be at the flanged end of the hose that the oil pump mates to. But now I'm wondering if the pump itself is the cause of the leak. The only means I can determine to provide lubrication to the worm gear that drives the pump has got to be a controlled leak around the pump shaft itself. I'm wondering if the clearances are too great allowing oil to drain through when it sits. If there was an o-ring on the shaft, I see no way to lubricate the worm gears. The pump is not serviceable and can't be disassembled.

I don't mind purchasing a new pump, but if it's not going to fix the problem it makes little sense to do so. I just thought I'd see if anyone has any thoughts regarding this.

newguy18

is the o-ring on the cap sealing?The worm gear is driven by the sprocket gear,which turns a shaft which rotates,pulling oil from the tank,and pumping it out onto the bar.If it is leaking aound the worm gear,replace the pump.

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old schooler

root66

Sorry, but I don't follow you on the o-ring on the cap. I don't know what cap you would be referring to. Are you referring the filler cap? If so, it's not leaking from there.

I've just returned from picking up the oil tank hose I ordered from the dealer. With all the oil and sawdust collected over the years, it was impossible to tell where exactly the leak was actually coming from. It's all cleaned up now and I intend to reassemble it and check it without the clutch and hub installed.

With a rubber nipple shoved in the hole to the oil tank, there are no leaks, so it's either the hose I mentioned or the pump itself.

I left out what may be a key piece of information. Sometimes, the bar oil will not leak out. This is what led me to believe that the oil pump is the source of the leak. I'm thinking that if the oil pump shaft stops in the "right" position it does not leak.

My local dealer does not have the pump in stock, but at $89, I may want to look at replacing the saw. I have to say that I have no idea what a comparable saw is priced at these days. It's a decision I'll have to make.

newguy18

There is noway possible for the pump itself the leak,i've tore down hundreds of saws,its either the hose,the filler cap,or the housing or its gasket.

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old schooler

Therrin

Funny you mention this problem, my 028AV does the same thing... I'll clean it all up and put it away, and if I take it out a month later, the whole bottom of the saw case is filled with bar oil. And it's not my filler cap o-ring either.

Lemme know when you find out what exactly your problem is and I'll check mine too.

newguy18

Check where the saw casing is either screwed or pressed togther,that is good for leaks.

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old schooler

Therrin

Nope, not leaking there.

newguy18

Then it has to be either the hose leaking or a crack in the casing,the pump cannot leak out all the oil,it only has a little bit in it,it cannot pick up any more oil unless the saw is running.

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old schooler

Therrin

I'm tempted to clean the whole thing up again and wrap it in paper towels to try to figure where the leak is.

newguy18

Or you could use tranny fluid,its red in color and its easier to trace leaks,no it won't hurt the saws oiling system.

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root66

Well, I'm new here and don't want to ruffle any feathers, but I have to disagree with the assessment that the oil pump could not be the culprit.

I'll try not to repeat what I've already posted too much or at least try to say it differently.

The oil pump shaft has a gear cut on one end and is an integral part of the oil pump housing after it's manufactured. The shaft is put into the oil pump casting and a pin is driven into a blind hole to retain the shaft. There is no way to remove this pin, so it essentially is one unit.

I explain this because unless there is an o-ring on that shaft, there is a direct path for the bar oil to leak out. It will come out of the hose (that I just replaced) into the oil pump housing and weep out around the oil pump shaft between the shaft itself and the housing. The oil pump shaft and the outlet from the oil tank are at the same level. The bar oil can gravity feed out of the tank until it runs dry.

There is no way to know if there is in fact an o-ring in the assembly because the pump itself cannot be disassembled. My thoughts are that there is no o-ring by design. There is engineered in, clearance between the shaft and the housing such that there is a controlled "leak" that serves to lubricate the worm gear driven by the crankshaft and the gear on the oil pump shaft itself. These gears have to have lubrication and there is no other means to provide it.

It's a theory! Without destroying the oil pump, I have no way to know.

So what I'm thinking is that there is no way to truly fix this problem. I seem to remember that when I bought this saw way back when, that it was a less expensive model. It had the same engine capacity and could accept the same length bars as more expensive versions, but was priced lower. I thought this would be perfect for occasional use and it has been. It's still going strong 22 years later. But, I think this is one of the reasons it was cheaper.

My case too will be flooded with bar oil after storage. Confusion though because it is sometimes far less than others. But, maybe it's because the oil level in the tank was low and there was less to leak out. I haven't paid attention that closely. After typing this out, I think I've decided the only fix is a new saw. I'm not spending $89 on a pump to prove a theory.

I see there's no editing posts here. I hope I have this all down right, I know in my previous posts I've made some errors.

I'll try not to repeat what I've already posted too much or at least try to say it differently.



Can I link to pictures here? It's disassembled on the bench right now.

Therrin

Root66,

I re-edited your post for you and took out the repetitious double-post inside it as you asked. It's all better now.

Yes! you can either post pictures uploaded from your computer, or link them in from another existing URL.

When writing your post, in the toolbar up above you'll see the paperclip icon, click on that and it'll bring up your options for adding a picture attatchment.

I'd love to see pics of what you're talking about, as I think that what you're saying is extremely a likely possibility. Newguy18 doesnt have stihl saws other than a 192T, so he isn't exactly savvy to the specific saw you're talking about.
I just recently rebuilt an 024 for a good friend of mine, and my 028 is almost the same type of design, so I'm really interested in your theory.

(actually, if you can't manage to embed them, just put up the attatchments normally and I'll embed them for you)

root66

OK, thanks for the help. I just flashed the BIOS on my motherboard today and I see that my card reader drive icons are missing! It's going to be a while before I can troubleshoot this and get them working.

I'll get the pictures up in the next hour or two.

Eric Frei

I get this issue on my palm saws (200T and 440), I replace the pump and it stops.

It can only leak from a few spots, process of elimination.

Oil chamber has no leaks or holes > Pick up line has no leaks or holes > oil pump has no leaks > delivery to bar has no leaks > should be no leaks so go back over.

But like I said, I find the pump leaks and because of the location it's a strip down to have a look where that oil is coming from anyway. You find the pool of oil directly under the saw not toward the front where the bar oil hole is. Sometimes though the bar oil hole can be blocked etc and you'll get oil pooling around that location generally when saw is running.

Newguy's idea of red tranny fluid is great.

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root66

The yellow line represents the centerline of the oil pump shaft.

The orange line points to the outlet from the oil tank. It's slightly obscured in the photo. The flared end of the hose I just replaced is covered by the oil pump casting. You can see the black tab down below. It's part of the hose and indexes it to the casting. The hose seals the opening in the tank, seals the pump inlet from leaking and functions as the inlet for the pump itself. The hose then runs inside the oil tank where a strainer is attached.

The red line is pointing to the gear on the oil pump shaft. Missing for clarity, is the worm gear that goes on the crank. It would fill in the void between the crankshaft and the oil pump body that shows up in the picture as a dark circle.

My theory is that the oil is leaking out around the oil pump shaft between it and the oil pump body. It's designed to do that to lubricate the gear you can barely see and the worm gear, which I unfortunately neglected to put in the foreground in the picture.

Now, having said that, I see no leaks as of yet. So maybe my theory is just bunk and the new hose has fixed it. That would be great. However, I can imagine what that oil pump shaft must look like to actually pump oil and I would not be surprised that if I rotated it somewhat and left in in that position, that I could induce it to leak. It may be leaking now at a very slow rate. It's not uncommon for me to use the chainsaw once a year. That's lots of time to leak oil.

It needs an o-ring to seal it, but with an o-ring, there would be no lubrication to those gears.

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root66

After sitting overnight, I see not one hint of a leak. I've reassembled it and I guess time will tell.

I'd say the hose was the problem. Once again, it appears I've over-analyzed a problem as I am prone to do.

Eric Frei

Hopefully it all is oK then.

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Bruce Hopf

I was able to Pick up my 024 AV Cheap from the Dealer. The Dealer thought that the Oil Leak was coming from the Crank Case Seal, so the Owner Traded in the Saw, because the Labour was going to be worth more than the Saw to fix it.
I disassembled the Chain Saw, Cleaned it all up nice in my Var sol Was Tank, and I filled the Oil Reservoir with Var sol, after I had Flushed it all out. I couldn't find any Leak, so I put a little High Temp Gasket Maker along the Seam of the Crank Case.
Once I put the Nicely Cleaned Chain Saw all back together, I then filled the Oil Reservoir up with Bar Oil, and placed the Fill Cap on. Once I set the Chain Saw Up Right, I found the Oil Leak.
The Bar Oil was Drooling out around the Oil Fill Cap, Down the Side of the Crank Case, and Down Underneath making it look that the Oil was Leaking from the Crank Case Seal. I replaced the Oil Fill Cap with a New One, and that Fixed the Oil Leak Problem.
I'd start with cleaning around the Oil Fill Cap Thoroughly, Fill the Oil Reservoir, Tighten the Cap Properly, and you might find your Oil Leak right away. Hope this helps. Bruce.

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MarcusKnight

Hi,Newby to the forum.Same saw same problem,stripped as others have and found that where the cone shaped pump inlet is,there is a drain at the bottom of the pump.It looks as though it may have had a rubber bung in it @ 1/8" diameter.This is the lowest part of the pump and as the oil leaks out the gear pump aerates and provides little/no oil to the bar.Contacted dealer to no avail.How-ever cut a self tapping screw down and screwed it in to a snug fit.No oil leaks and pumping fine.Hope you find this is your problem and still have your Sthil !