Signs of an oily clutch

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JHZR2

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My 1991 BMW seems to leak a little bit of oil though I can't trace it. Perhaps it burns it though there's no real indication in the exhaust and no smoke. It has the original clutch at 150,000 miles. I'm wondering though about what happens when a rear main seal leaks onto the clutch.

The reason I ask is because when I start off in first gear, the clutch starts to grab just fine. At about the last quarter of the clutch pedal motion, instead of fully catching up it almost feels as if there is a slippage and then it locks up hard. Maybe it is a shuddering sensation as a good way to describe it.

So because of this I'm wondering if there could be oil on the flywheel or clutch that causes such a behavior. It is very intermittent and there is no signs of clutch slippage using any of the typical tests. That's why I have to wonder if there is just a slow leak of oil onto the flywheel that maybe just burns off after a shift or two.

Even if this happens generally if I am shifting a lot in and out of different gears and using the clutch, it will not happen again until I sit for a long time, like either at a long stoplight or turned off the car to park for a few minutes.

So what would it feel like if I had oil on the clutch?
 
My old 65 TR4 had a bad rear seal and leaked on the clutch.

It felt exactly as a worn one would, and my test has always been to apply full throttle at peak torque in high gear, perhaps 4th in your case.

Your symptoms sound more like a bad throwout bearing or perhaps a bad slave cylinder/master cylinder
 
It takes a pretty big rear main leak to actually get on the clutch material in most vehicles. The leak is on the opposite side of the flywheel from where the clutch is, so it has to be leaking fast enough to fling off the flywheel, drench the inside the bellhousing and then drip back onto the clutch. In other words, you usually can SEE oil on the ground long before it would ever get on the clutch.

If I had to guess, yours sounds like the pressure plate is hanging as you release the pedal then snapping the rest of the way in quickly. Maybe because the clutch is worn and the fork (or slave cylinder- not sure how your vehicle is made) is hitting an area of travel near the end of its range.
 
The clutch may be worn given the number of miles on it, but it fully grabs under any test that I do such as those mentioned just above.

Both the slave cylinder and the throwout bearing wear from use, correct? I almost entirely drive stop and go, stop lights and traffic, so a use related wear out would be expected. I never keep the clutch pedal pressed though.

Could it be that the clutch is worn to the end of life but yet grabs fully? I assume I would do the full clutch assembly and slave cylinder all at once not just one or the other? You always do the master if you do the slave, right?
 
It isn't at all necessary to change the slave cylinder when changing the clutch, but it could make the job MUCH easier depending on where yours is.

I've never heard the "always do the master if you do the slave" either. I suppose it's sound logic, but I don't hear of master cylinders failing that often. Then again - maybe dead men tell no tales, eh?
 
A chattering clutch can be a indication it has gotten some oil on it... With heavy amount of oil, they generally slip with more than light/moderate throttle...
 
Your description of normal operation during the first part of clutch uptake, then a feeling of slippage, then a hard lock up as you finally take your foot off is exactly how my '87 325 felt when I had a front transmission seal leak. Sometimes it was more obvious than others but was most noticeable on a fast start or during faster driving. The clutch never slipped when flooring it in gear and would always grab hard when you finally let your foot off the clutch.

My clutch had been replaced within a few years so i knew it was not a clutch wear issue but with your miles on the original clutch it could be just worn out.
 
Sounds to me like a worn clutch, you would be able to see the oil dripping before you would get it on the clutch.

If it bothers you enough and you plan to keep the vehicle a lot longer, replace the clutch otherwise just try not to notice it and get used to it.
 
The clutch in our '99 Accord worked just fine with no slip at all until it abruptly failed in service last fall.
When I say "failed" I mean that the vehicle lost all drive in any gear while being driven down an interstate highway.
New disc, pressure plate, throwout bearing and flywheel (micro cracking) and all was like new again.
 
Originally Posted By: silverrat
I have this happening to my Accord. Slow clutch fluid loss but no leaks.


It doesn't evaporate...
 
Originally Posted By: JamesBond
Your description of normal operation during the first part of clutch uptake, then a feeling of slippage, then a hard lock up as you finally take your foot off is exactly how my '87 325 felt when I had a front transmission seal leak. Sometimes it was more obvious than others but was most noticeable on a fast start or during faster driving. The clutch never slipped when flooring it in gear and would always grab hard when you finally let your foot off the clutch.



Mine may be the same trans, and it is a good point that I should try to check/change the mtf perhaps if I find it to be low, it would be an indication. The amsoil fluid holds shift feel much better than redline so I haven't changed it in a few years.
 
I've had that feeling on first a Saturn and then my VW. The Saturn would not have it after letting the dealer do an oil change though; I'm guessing the grease monkeys might not drive as nicely as I do... I generally had full clutch engagement around 1000-1200rpm IIRC on the Saturn, still do on my VW. [It hurts to drive the Camry.]

I don't know if it's a drive-by-wire issue on my VW as it is only felt when cold really. Just this sudden lurch as it finishes catching, maybe it's more throttle related. Been doing it for a long time, yet it just got a new clutch at the begining of summer (bad DMF--thanks VW for more stellar engineering) and there was no issue with the clutch disc, oil contaimination, etc.
 
A real bad rear seal leak can get on the clutch. It slings all over and then drips down on it.
Normally, a little leak is designed to never hit the clutch - it just goes down and away.
Anyways, an odd thing with fluid on brakes or clutches is that they can actually grab, not slip. The heated goo often makes it grabby.
Is this grabby cold then gets better?
The rubber or metal dampers in the disc can go bad, There is an on/off sensation instead of a smooth transition.
If she does not slip when driving, this may be the problem.
 
How do you differentiate betweeen rms leak and a trans front seal? Little noticeable fluid loss when checked but drips when hot and inside of bellhousing is soaked with dirty mucky fluid.
 
Originally Posted By: silverrat
I have this happening to my Accord. Slow clutch fluid loss but no leaks.
check the carpet and insulation for wetness.
 
I helped a friend change a rear main seal in a Jeep 4.0 that was completely shot. To the point that it would just be gushing oil out of the back of the engine and coming out of the starter. None got on the clutch.

It seems like yours has some sort of fluid contamination. Usually RMS leaks will come out somewhere and cause a drip. Otherwise you will be smelling the burning oil.

I will occasionally get a bit of chatter on the Focus - no loss of fluid from anything, though. I suspect it's just a lot of city miles combined with a polyurethane transmission mount that transmits EVERYTHING to the cabin.

Clutch appears to be good, though. Pulled my camper up a hill with it foot-to-the-floor for a minute or two without any issues
 
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