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Small oil leak at bottom of engine (DL1000)

13K views 36 replies 10 participants last post by  MAZ4ME 
#1 ·
I've never had an oil leak before, but for some reason my '07 Vee started seeping a little oil on a recent 1000-mile trip.

Part of the return trip was 100+ miles of forest roads. I found some gravel inside my skid plate, and quite a lot of accumulated crud on the bottom of the engine. when I got home. As well as a small patch of (now-gritty) oil, on the inside surface of my Enduro Guardian skid plate, clearly indicating some kind of recent leakage.

Near as I can tell, the leak started some time during the return half of the trip.

Before departing home, while at my destination, and prior to heading back home, I was having a look at the engine daily, to be sure the stator cover seam wasn't leaking. That's because I'd had the cover off a few times recently due to some stator issues, but didn't have time to wait for a new gasket before my trip. Indeed, that seam did not leak any oil in the days leading up to my trip, verified as late as the morning of the day I headed back home. It's still possible that seam did start leaking on the way home, but I can't be sure yet.

Post-trip, the whole bottom of the engine was dirty enough that I couldn't be sure where the oil was coming from. Here's the area I mean, cleaned up:



It looked like maybe the oil was coming from the seam with "0706" on both sides. Or perhaps around the oil pan drain plug? There was so much general grime that it was impossible to tell. I suppose the oil could be coming from higher up, but it doesn't look that way so far.

I did an oil change not long before the trip. Torqued the drain plug to spec, so how could it leak?

I've had the aluminum EG skid plate mounted for a couple of months. As you would expect, there's not a mark anywhere on the bottom of the engine suggesting damage. Whatever this is, doesn't seem like it was caused by anything hitting the engine case.

So what's going on here?

For now, I cleaned up the entire area I think the leak was coming from. I am letting it sit overnight, skid plate off, with a clean shop towel on the floor to highlight any drips.

FWIW, mileage on the bike is about 37k.
 
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#2 ·
Oil, like mice and rats can seep through the smallest of seams. I've got oil seeps on my Toyota vehicles the mechanics make much ado about. But as clean as we'd like our bikes to be, some seepage may be inevitable. I look at the back of the 04 Wee I have and see some seepage on the rear cylinder but no spots on the floor so it isn't a constant flow.
If the oil is pooling under the engine overnight you may have a real concern.
Otherwise, like a classic Brit bike it may be a preservative.
 
#3 ·
Just asking, but did you replace the oil drain plug gasket when you last changed oil? Many re-use them (over and over again), but they are actually 1-time use crush washers. Ive seen them leak.
Many auto parts stores carry "Tracer Oil Dye" for use with a UV lamp in an unlit garage. You can buy a small UV lamp, some are battery-powered, and they usually come with a pair of yellow glasses for use with the dye/light combination. These work well. Put the dye in the oil, ride for 100-300 miles, put on the glasses an with the bike in a darkened area and UV lamp in hand, look for a bright green oil trail. I used them all the time at work for engine oil, transmission fluid, coolant, and a/c refrigerant leaks.
 
#4 ·
One place prone to leaks is inside the front sprocket cover. It can be from the clutch pushrod seal or output shaft oil seal. Clean Out front sprocket area!
 
#5 · (Edited)
No, I've been through 2 oil changes now and haven't replaced that gasket you mention. I don't know where to get one.

Well, I could get one from Partzilla I suppose, but I object to paying $8 shipping for a $1.16 washer.

If I knew the size, I could probably pick a suitable replacement up at a hardware or auto parts store.

Then I'd just have to drain the oil into a suitably clean container, put drain plug back on with new crush washer, and torque to spec. Then refill oil.

I cleaned out the front sprocket area a few months ago. There was actually not much crud there at all. Haven't had the sprocket cover off since, but I'd be surprised if it had accumulated enough crud since then to cause an oil leak.
 
#6 ·
A 12mm crush washer will do the trick. I like a solid aluminum or copper washer. I got mine from a Honda dealer. The Suzuki crush washer is hollow and practically disappears onto the bolt. Make sure to get the old one off before adding a new one.
 
#7 ·
Nice, I'll give that a shot.

I don't think I'm going to see any leaks while the bike sits. I'm guessing the seepage will only happen while the oil is hot, and therefore a bit thinner than when cold.

I haven't ridden since Sunday because it's been too cold in the mornings to go without heated gloves (another tale of woe...). But replacing the crush washer would be easy to do while I wait.

I guess once I get my replacement heated gloves or the weather warms up, whichever comes first, I'll ride a bit & see if the seepage shows itself again.

I've cleaned all the suspected areas of leakage, so it shouldn't be too difficult to figure out where it's coming from.
 
#9 ·
If the drain plug gasket isnt leaking now you dont need to replace it at this time. But...next time you change oil, take your drain plug to an auto parts store and get a copper metric drain plug gasket. The Suzuki gaskets are steel, but most Japanese automotive drain plug gaskets are copper or aluminum. I used to get them in bulk from work in 12mm, 14mm, 16mm, and 18mm sizes. Take your plug with you to get the proper size. And I do use a torquewrench on them every time.
 
#21 ·
I might be draining the oil anyway. Or does it sit low enough when cold, that it won't come gushing out when I remove the right side engine cover?

I ask because I decided to go ahead and do a water pump rebuild, while I wait for a new gasket for the stator cover & for my heated gloves to be replaced. The weep tube has been dripping a little off & on over the last year, and now is as good a time as any to do the work. That involves taking off the right side engine cover.
 
#10 ·
"Torqued the drain plug to spec, so how could it leak?"

That's could why. Those threads are fairly delicate and using a torque wrench it's easy to overtighten and strip the threads. There are several options for repair but the easiest is a self cutting plug with a smaller drain bolt in it. Most auto spares places stock those.

The other likely contender is the clutch push rod seal, a self tapping screw and a pair of pliers will get the old seal out, be careful to not push the replacement in too farif you replace it.
 
#11 ·
Sorry but the only way a torque wrench will strip a thread is if it is neglected to the point it is way out of calibration or if it is misused. Tools don't strip threads, people do.
 
#19 ·
Yup.

I do find it's easier to accidentally over-torque fasteners with very low values - say, 7 lb-ft and below. Maybe because it's so little force, even with a 1/4" drive torque wrench. Or maybe the last time I did it, I wasn't used to the wrench and/or F'd up the conversion since it's marked in lb-in instead of lb-ft.

I tend to use "hand-tight and blue Loctite" on those things lately. In some such cases, as with the bolts that hold the stator to the stator cover, you're supposed to use thread locker anyway, so the torque value is really more of a guideline.

The oil pan drain plug is not such an item though. 16.5 lb-ft is a decent amount of torque, & I haven't found it difficult at all to properly thread the drain plug back in, after 3 oil changes.
 
#12 ·
GW, the Mazda MPV and Tribute oil pans were notorious for stripping. And many times the customers came to us knowing the pan was stripped. They'd come in for an oil change, the tech would drain the oil, then the plug would spin and not tighten. Then it was our fault because.."You guys stripped my oil pan!" Our service manager sided with the customer.
So...as Shop Foreman, I got all the got all the other techs together and instructed them to torque the drain plug to spec BEFORE removing it. If it spun, it was stripped, and since we didnt remove it and drain the oil, we knew it had come in stripped. The service manager was pissed--because he coudnt blame us and had to tell the customer that his pan had been stripped previously and give him an estimate for the repair. Worked like a charm.
 
#14 ·
I misused a torque wrench once when tightening a drain plug. I didn't get a click by the time it should have happened. A look at the wrench showed I hadn't set the torque and it was at zero where it needs to be stored. That was my fault, not the tool's. I didn't blindly trust the tool though and kept my head in the game so I didn't do any damage. That wasn't luck. It was staying aware. I've made plenty of mistakes but it seems it usually takes a double lack of awareness to do real damage.

The one time I did real damage was in doing a valve job on a Honda CB500. I got the cam chain one tooth off. That's mistake #1. Then I rotated the crankshaft until it hung up so I used more force. Mistake #2 bent a couple of valves.
 
#15 ·
I contend that this is very unlikely to be the oil pan drain bolt leaking, and oil migrates many times where it isn't leaking. You had the leak occur during a trip correct, it appears to me that all the dusty conditions and a mucked up chain, could be causing your clutch slave seal to be leaking or the push rod seal.

Part of the return trip was 100+ miles of forest roads. I found some gravel inside my skid plate, and quite a lot of accumulated crud on the bottom of the engine. when I got home. As well as a small patch of (now-gritty) oil, on the inside surface of my Enduro Guardian skid plate, clearly indicating some kind of recent leakage.
 
#22 ·
I had a 1973 CB500/4 and bought the funny Honda tool with the nut and screwdriver thing for adjusting the valves. Heavens knows where that went.
Never had a problem with that. But reading the feeler gauge is an acquired art. BMW's were easy, I always set the valves loose and noisy.
I never really bothered with a torque wrench since they can really be fickle especially in the hands of the novice. Firm is firm and not over tight. It's only a 10 mm wrench.
Klickers be damned. Don't forget to have it calibrated occasionally.
 
#24 ·
While I was putting the bike back together tonight, I noticed that there was a tiny amount of oil that had finally dripped on to the shop towel under the engine.

Those of you who were betting against the oil drain plug were correct.

It also wasn't coming from the bottom of the seam between stator cover and engine, or from the crankcase seam on the very bottom of the engine.

I couldn't trace the exact path, because there was a lot of grime left on higher areas of the engine. But it was clearly oozing down from somewhere above. So I have a hunch it's that clutch pushrod seal. Will verify when I get the car running again.

Last thing I did tonight was an oil level check (per the owner's manual). The very good news is that even with the oil I found inside the skid plate and elsewhere, it seems the leak is VERY VERY slow. I had the oil at the "F" mark after the last oil change, and the level was not down visibly.

So about that clutch pushrod seal: Looks like the major pain in the butt is going to be obtaining said seal. Found a thread here detailing how to swap this seal. Not too bad - don't even have to open either side of the engine.
 
#25 ·
Dang, I feel bad seeing your mechanical misfortune here. With the stator, water pump and other issues going on the Strom needs lots of TLC. Now the car is on the fritz too? Hit me up if you'd like to use one of my bikes or something. They can use a little more exercise.
 
#26 ·
What do you use to oil your chain?

Reason I'm asking is that if you use something light and runny (like oil dispensed through an automated solution like Tutoro or Osco), instead of something sticky (like spray-on wax), you might just be seeing the excess oil from that, instead of engine oil.

The chain makes the smallest bend around the front sprocket, so if any excess oil is flung off, it will most likely happen in the front sprocket area. There's a drain hole down there which runs along the side of the engine case and down. So any oil off the chain will be dripping from the case and may easily be mistaken for engine oil. Especially if that area isn't too clean to begin with.

On the other hand, any engine oil that makes its way through the pushrod seal, and any hydraulic fluid making its way past the slave cylinder seal, will also drain through that drain hole. Both would be bad news.

You don't have to drain the oil to just take a look at the front sprocket area. I'd start there, just to make sure I wasn't chasing ghosts.
 
#27 ·
I use DuPont Chain Saver. Does that help?

Maybe it is just chain lube? I did the last chain lube job on the road, before I left Arizona. I did it the same way I've always done it & have never had the appearance of an oil leak before, so it's hard to say what's going on.

I'll know more later this evening, when the bike's had a chance to cool down & I can take a look under that front sprocket cover.

The tiny coolant leak should be an easy fix. It only seems to happen when the bike first runs after sitting cold a few days, and seems to be limited to a slow seep from the thermostat end of the radiator inlet pipe.

Once I get my car running again, I'll have a chance to get all the stuff out of the way (again!) & swap that pipe.

Even if it IS the clutch pushrod seal, that's just a matter of waiting on the part. Swapping it shouldn't take more than half an hour, tops.
 
#29 ·
Good news: it isn't the clutch pushrod seal.

I got that sprocket cover off and while it was pretty filthy in there, the dust caked around the pushrod seal was absolutely bone dry.

The drain hole BackPacker mentioned was fairly clogged, so I killed a dozen or so Q-tips and some rubbing alcohol cleaning up the whole space.

I also killed some grime a little lower down, so maybe if I get further drips I'll see them if they come through that area.

For now I have bigger fish to fry, like my car not starting, so I'm going to put this mysterious super-slow oil leak (or maybe it WAS excess chain lube...) on the back burner.
 
#32 · (Edited)
Yeah, I'm getting a bit more than 2 drips overnight! It's not a torrent, but after riding to and from work 3 days last week, I had a decent oil slick starting inside the skid plate by Friday evening.

Although I could not observe oil leaking from the seam involved, I had an extra generator cover gasket (11483-02F10) on hand & figured what the heck, might as well replace the old one like the shop manual says. Since I ruled out a clutch pushrod seal leak, that gasket was the only thing I could think of that could possibly be producing a leak.

I spent about an hour this afternoon, opening up the stator cover for at least the 4th time in the past year, then cleaning up the interface between stator cover and engine block. There was a good amount of residue, in places, bits of the old gasket that were stuck to the magnesium.

Lots of elbow grease and a couple of Scotchbrite pads later, the faces of the cover & engine block where the gasket sits were clean & shiny again.

I installed the new gasket, replaced the cover, and torqued all 11 bolts to spec. Went for an hour's ride a few hours later. So far...no more oil leaking! I'll know for sure after a few more rides.
 
#33 ·
It's been too cold to ride here the last few days, but I've had the bike on the side stand and no more leaks, so I'll call it good.

I also realized I had done a dumb thing a while back. When I installed my Enduro Guardian skid plate, I removed the brackets for the plastic engine skirt. Well, those two bolts can go back on without the brackets...and they help hold the stator cover to the engine block...and they're at the bottom, the most likely place for a leak. So I put 'em back in.
 
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