Harley leak/drip due to viscosity?

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MoreCowbellAz

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I'm trying to solve a mystery here. I recently changed the oil in my 2000 RK from Rotella 15w40 to Valvoline 4t 20w50 syn, and also cleaned and reoiled the K&N airfilter (it has the SE K&N kit). Since the change I've gotten a small amount of oil dripping out of the air filter housing. I've never once gotten this before so it has to be something to do with the new oil change. It's frustrating the [censored] out of me.

Here's what I know for sure: The air filter is definitely not over oiled, I was careful about that and also the drip is is amber whereas the filter oil is red. Also the engine oil sump is not overfilled, when hot it read exactly at the full mark. When I first saw the drip I removed 4 oz of oil, no change. Last night I removed another 8 oz, haven't ridden it yet so I'll see what happens. The hot reading is now just below halfway between the add and full marks.

I never had this problem with the 15w40. I'm suspecting that maybe the higher viscosity of the new oil was just just enough to cause an increase in pressure just enough to blow a bit of oil back out the breather vents. Maybe that combined with the high temps here in the summer, and also admittedly I've been riding a bit harder as of late. Doesn't make a lot of sense to me why this would start all of a sudden, but as I said I can't think of anything else.

One last tidbit, when I did the oil change I changed the filter as well. The refill took 4 qts exactly to get it to the full line when hot. I vaguely was expecting 3.5 qts but maybe my memory isn't correct. Regardless, full is full right?

Any wisdom out there on what's going on here?
 
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Is it actually motor oil coming out of the airbox??

Thats a big factor, cause otherwise you are dreaming thinking its the motor oil change.

If it is motor oil , and not over full, your rings are probably shot, and you have so much blow by, its forcing oil out of the valve cover vent into the airbox, that is the only way it can happen.


I have zero faith in K&n airfilter set up, but remove the filter and look for a big pool of motor oil inside the air box, if that doesn't exist, look towards your k&n oiling, of some kind of fuel flooding.
 
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Yeah its definitely motor oil. That's why I'm stumped, doesn't seem the rings are shot (19k miles, babied by my dad, uses no oil, doesn't smoke, etc), and absolutely nothing different except I changed the oil. But immediately upon that change, started dripping out the air cleaner, never before in the 5k miles I've had it. Not a lot but a few drops I noticed on the engine cases.
 
The vents are the airbox bolts, and they depressurize through the head. The rings are not the only thing to let more blow by, maybe valve seals are going. On my 99xl the rear cylinder exhaust valve is moist when I took the pipe off, and the front cylinder is smoking when warmed up. Sad thing is mine only has 16k on it.
 
Originally Posted By: endeavor to persevere
Usually when that happens the oil is over filled. You don't fill to max but in between the low and max marks.


I have to agree, the key here is, you were expecting it to take 3.5 quarts and it took 4 quarts, plus you say you have been riding it a little harder. I suspect now that you reduced the oil level to the mid point you will see oil drip subside.
 
It's oil vapour from being overfilled.

There's nothing wrong with the rings. I've seen twin cam engines with 150000 miles on them,so you just getting broken it.
If cold and you put in 4 quarts you were overfilled and when the oil got hot and expanded it got sucked into the breather. I saw it on my dyna when I did my first oil change.
Do not overfill.
 
I'll get some oil if the fill level is full and I get out there and get on it. If the level is almost down to 3/4 full, no oil in the air filter box.
Maybe wrong dipstick, dunno. Or that's just the way it is. Go figure.
 
Don't sweat it, chances are you overfilled.

Not 100 percent sure how it works on an RK - my softail has a dipstick...But if it does:

Go for a decent length ride, get the oil nice and hot. Check the oil level. If it's above 1/2 or 3/4 to FULL HOT, you most likely over filled. Wipe off the oil and then check again after a few rides.

Common thing with HD's. Guys will fill up the amount of oil specified by the manual and get oil vapor. If you keep it 1/2 qt or so short, you won't have any problems.
 
That's part of why this seems to be an odd issue, the dipstick was exactly at the full mark when hot. Even though I don't take a dipstick as fine science, it wouldn't seem to be that overfilled even if the dipstick was a little inaccurate. Especially when I kept it at the full mark with I ran 15w40 and never has this problem. Right now the hot level is just shy of halfway between add and full marks. I need to get a good ride in to see if it makes a difference.

It does seem HD's are sensitive to oil levels. When I first got it I changed the trans oil and overfilled by just a few oz (because I checked it on the side stand rather than upright), and it misted oil out of the filler hole. Once dropped to correct level it went away 100%.

Hope it's the same with the engine oil. Wouldn't make sense to me given that it was fine with the 15w40 with everything else being the same, but who cares if it solves the problem.
 
Quick update, after removing 16 oz of oil from the sump the problem seemed to have stopped, no drippage after a normal run. That makes it 3.5 qts in the sump which puts the hot level about 1/3 between the add and full line on the dipstick. So for whatever reason it doesn't like to be "full" according to the dip stick at least not with 20w50. Why it's ok with 15w40 I have no idea but whatever, I'm just happy to be done with that mystery. Oil drips make me crazy.
 
Dude: next time put a stay free mini pad inside the air cleaner "football" cover if you have a cover. This is not a joke. My lowrider would drip occasionally. 1 pad...done.

It is normal for a Harley engine to push oil out the air filter when driven on the highway for long periods.
 
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Originally Posted By: Doog
Dude: next time put a stay free mini pad inside the air cleaner "football" cover if you have a cover. This is not a joke. My lowrider would drip occasionally. 1 pad...done.

It is normal for a Harley engine to push oil out the air filter when driven on the highway for long periods.
So much for the macho Howley tradition.
 
I actually considered that, I researched the [censored] out of this problem and saw lots of people keep their Harley "fresh" the way. Lol

Update to my original post: I'm sure folks will make fun of me but my "fix" of lowering the level didn't work after all, seems like I was home free then saw some minor drippage again. So after much research I decided to change course and get a catch can/breather vent setup and not have my breather vent to the air box at all. It's not a lot of oil to begin with, just enough to me messy, so a small can would do me for quite awhile without having to empty. Super simple to install and fits directly behind the football.

Close second to that would have been to route the breather vent directly into the throttle body rather than just the the backing plate off to the side of the throttle bodies. I came up with a simple method that would be completely sturdy; 1/4 copper tubing fits perfectly into the breather hole in the back plate, red locktite cements it in, tubing bent to a small radius puts the opening directly at the throttle body so the vented oil would be sucked into the intake and not drool down the side.

Seems either method pretty much takes care of the symptom, if not the "problem". I chose the catch can option mainly because I like the idea of keeping the oil/oil mist out of the intake. Probably not a big deal either way. I know I'm not being environmentally friendly with that option but I can always easily undo the mod if I ever want to.

I know a lot of folks know tons more about Harleys than I do, but I question the whole oil level argument with these bike, at least the dry sump ones. I was always skeptical oil level would make much difference, this adventure certainly hasn't shown a bit of difference with +- 20 oz of oil.

Anyway, hope it helps someone out there.
 
No it doesn't, you're supposed to check the oil level with it on the side stand. The dipstick has an add and a full line, and the manual says the cold full level is half way between. I always use the hot level, right now it's about half way between add and full. FYI hot vs cold is about 1/4" on the dipstick.

What appears to be the case is there are a lot of malfunction reasons why this type of oil carryover could occur, plus if you have big bore or stroker kits, but also lots of Harleys just do it because of the design. I'm fairly certain I don't have any mechanical issues, but the one thing I can't understand is why none of this happened with lighter grade oil. Maybe it's the narrow flow back galleys (whatever they're called) in the heads that keep too much oil in the heads. I'm at the limit of my Harley know-how there.

But I gave up, catch can will be installed in a few days, I'll report back if anyone is interested in what I find.
 
Is this engine an Evo? If so, it needs a special oil filter for the low pressure pump. Did you use a genuine H-D filter? FWIW my 2007 Dyna 96 Twin Cam takes 2 1/2 quarts to fill it up w/filter for an oil change.
 
Last Evo big twin was in 1999 models. So this is a Twin Cam.

Evo's do not need a genuine HD filter. You can use any that is made for the application such as a Wix. Last I heard the HD filters were made by Champ Labs.
 
Correct, it's a TC88, all stock except for a SE air filter kit, which means backing plate and a K&N filter. if you mean oil filter, yes that's an HD.

Someone check me on this………..my understanding is that one reason these motors can drool oil out the breather is that the oil passageways that let oil drain from the head back to the bottom end are narrow which in turn can cause too much oil to stay in the heads and can overwhelm the umbrella valve. IF that's the case, wouldn't it stand to reason that a thicker oil would make this worse? That's the only thing I can think of that would be the culprit in my case, since it never leaked before in 5k miles with 15w40 but leaked immediately upon switching to 20w50. Everything else identical, Oil level was the same, always kept it at full. Right now I'm all way down to about 3/4 qt below the full mark (3.4 qts actually in the motor) which makes zero difference to the drooling problem.

Even though I've gone the catch can route, I'm still curious to learn.
 
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