Oil leak from rear crank seal?

[catimann]

I replaced the non leaking 85,000mile rear crank seal because I did the clutch and the stuff you do to the trans when you have that out.
Great pain was taken to have it all clean to use a seal (V.R.) that matched the factory seal and to install it properly. It leaked in two days.
upon removal of the trans and fly wheel it was the new seal.
Here is where it got interesting because it was new and I wanted to know why. I measured it's ID and found it was 88.8mm (average of 10 measurements taken around the dial, so to speak). For a seal that fits a 90mm shaft that is not tight. The new, new seal (one with BMW on it and does not match the original seal, that also had BMW on it) has an ID of 87mm. That would seem tighter.
So I used the seal install tool and followed all the std install procedures (checked the crank surface for roughness) and put the new new one in.
IT LASTED A HALF HOUR!

I have not ripped out the trans again (and I do mean ripped because now I will have that sucker out in an hour or less, once the car is up) because i thought to ask here if there was some other place I can't think of where the oil may be coming from? The leak is from inside the bell housing just like it was last time and just as it shows on some youtube vid I watched before. However I need to ask just to be sure.
Also any note or links to a proper seal install would be helpful because I feel as if I may have done something wrong. Mind you I have done this many times over the years on other vehicles and none of those leaked.

Thanks in advance.
******************************
Note: The result of removing the trans etc. was to find a non leaking crank seal (I guess the new single lip BMW seal does the job) I turned around to find a wet seal in the trans. That (BMW) seal is on the way. In this thread someone said to look at the CCV and I replaced it before going and taking out the trans. The CCV was relatively clean (I cut it in half with a saw) but still the replaced one did have less suction in the test than the new one. Perhaps the diaphragm had a hole, it was almost 20 years old so replace it.
Lastly my install of the crank seal was not exactly as the last post by Randy stated. i will reply below that.

[LannVouivre]

Did you inspect your CCV?

[catimann]

Did you inspect your CCV?

Not yet but after reading a lot (FAQ section and all sorts of other links) and looking for info about what is normal (Not much found about that but maybe I missed it.) I started to look at symptoms of a CCV issue. Mine seemed to have none and then I pulled the dip stick. It sounded like sucking the last bit of milk out of an old glass milk bottle with a big long straw! My friend looked at me and said "That's not normal." Yeah after 40 years of cars ownership I had never heard that before either.
So my original problem is a leaking rear main, the second new one I have installed and it was done correctly and thus the question is the seal F'd?
Does this excess vacuum issue destroy the seal or will it go back to sealing? I thought to try and experiment by always pulling the dip stick each time I stopped the car. This is where I noted it does not do it (The sucking noise) every time. (That may have to do with how long it was at idle before I turned it of?) It seemed to give me less of a leak but this is not conclusive.

I also read in a CCV explained site that a Throttle Wide Open you will get pressure build up in the crank because of a lack of vacuum. So I do plan to replace this CCV because of age and this problem but I still wondered if there is a way to clean it? Say with Sea Foam sprayed down the Valve cover end and the dip stick end removed? Based on pictures of the systems there are no valves of moving parts and it just gets gummed up.

Crazy idea or? So is my rear seal screwed? Can you clean a CCV?

diag_pg.png

[nevan]

It does sound like CCV isn't working correctly. Is your engine modified with some sort of forced air?

Anyhow, even so, it's hard to imagine the new RMS failing so quickly... In my experience, oil pan gasket on these cars take some extra care (in cleaning pan and especially aligning it back to the block) than any other cars' I've worked on in past. Maybe it's just due to lack on paying attention to details or simply I have a lousy wrenching skills, but I had to assemble/disassemble it several times just to get it mounted right without leaking. And I definitely wouldn't like to repeat it again.

[catimann]

No the engine is stock. The oil pan was not touched. There is enough play in the seal to get the carrier plate on and cleaned the lower area very thoroughly then used a thin film of permatex on both sides to get it sealed. Also in the two corners where the carrier mates the block. The first seal that leaked was only leaking around the crank end. (I did not check the crank end with a mic or machinist square but by hand for roughness and any type of groove and none found)
The pictures I took of the crank end show a different surface finish where the seal sat but I could not feel any groove. (I worked with aerospace finishers for years and you can feel very minute differences in metal surface finish.) That said I looked at this before installing the first seal.

[LannVouivre]

The CCV uses a rubbery diaphragm. You can put a plastic bag over the oil fill cap opening with the engine running. If it sucks the bag in, the diaphragm is probably ruptured. Mine almost ripped the bag from my hands. I'd have to read on how the BMW system works again, to be sure.

[catimann]

I looked through the Bently manual on how to remove a CCV and it seems to not exist. (There is a dwg of it on page 100-11 and some mentions of how to disconnect the top hose.) Not in the Index, not in Cyl head removal.
Does anyone know of a link to a Re n re of this? I found one but it is for a M54 and in it the guy put his car up for sale. Glad to hear it should be easier for the M52.

[LannVouivre]

http://www.bimmerfest.com/forums/#/topics/534005?page=1

[catimann]

I have finally had the time to replace the CCV system. I took the old one apart and then cut it into pcs to see the inside. Wanted to know what was plugged or wrong. The thing was not plugged at all but perhaps the diaphram had a pin hole. Either way the suction at the oil filler is now less than it was before. The other suction sound that came when removing the dip stick also seems to be gone.
However the oil leak from the rear main seal is still present.
Any ideas are appreciated. Besides replacing the damn seal, again. That I will probably start today.

[zellamay]

Here is your biggest clue: " I replaced the non leaking 85,000mile rear crank seal " What this says is the problem is nowhere else. It is in the seal or the seal install. So, I would say don't bother to install another seal until you can figure out what is going on. I'd start with the fact that neither of the seals that you have put in match the original one (the one that didn't leak).

[gmushial]

It doesn't look like RandyW has chimed in on this... I would poke him and see what he thinks [I haven't met anyone that has nearly the level of understanding of these engines that he has].

[catimann]

Here is your biggest clue: " I replaced the non leaking 85,000mile rear crank seal " What this says is the problem is nowhere else. It is in the seal or the seal install. So, I would say don't bother to install another seal until you can figure out what is going on. I'd start with the fact that neither of the seals that you have put in match the original one (the one that didn't leak).

Yes I have considered that it is the seal or the shaft or surface finish. This time I will do a far better inspection of the surface, take pictures, measure it with a Micrometer I have from my father and go from there.
However I must point out that Both seals were the right seals. The first replacement was an exact match to the factory one, same material, same dimensions (as marked on the exterior surface), same construction with the internal spring. I first went to the BMW dealer and asked for the replacement seal and rejected that one because it was not exactly like the factory one. The one BMW was going to sell me (is a single lip one and they say it is what they use now) is the one I used the second time. This second one has a different construction but if it has BMW right on the seal then one would thing it is a close enough "match" that I can use it. The fact is I used the right seals and went through pains to get the right ones but still have a problem.
I did not use a machinists straight edge to check the shaft last time but I will this time because I am lucky enough to have inherited one. I know where I can get a surface finish gauge as well so I may borrow that. I doubt it is the finish though because I didn't scratch it and checked it when I oiled it prior to the seal install. Just maybe there is a slight groove in the shaft.
BTW Randy has given advice in a past post.

[zellamay]

Well. something is different than before you took it apart. (obvious I know) I doubt it's the shaft because the old one did not leak. What about the shaft outside the sealing surface, that you have to slide the seal over? Are the new seals in exactly the same place on the shaft as the original seal? Are they seated in exactly the same place, (not moved out by a thicker gasket for example) Do you have the correct side facing forward? Are you sure it's the new seals that are leaking, and not the housing/mounting?(sorry, I'm fishing here) You can look at it before you take it apart.

[Randy Forbes]

Did you use the supplied guide (included with BMW-sourced seals)?



Did you replace the gasket?



Did you use sealant where it's required, and only where required?



Did you lubricate the seal before installation?



Did you torque the fasteners back to spec (first by snugging/loosening, alternating between the pan bolts and carrier bolts)?

[catimann]

In the first post I have written a summary of what was done so people don't need to read all the filler.
However here I want to answer the above 5 steps Randy posted. Thanks those are very nice and clear steps.
Step 1:Yes (not the first time around though). 2: Yes. 3: No I added some extra sealant along both sides of the metal Deforming gasket and along the mating surface of the Seal housing and the oil pan. (the amount used here was VERY minimal, like taking a drop of oil on your finger and putting it on an oil filter rubber) 4: Yes lubed the seal and crank. 5: Yes
As I stated at the top I found the crank seal is dry and my trans input shaft seal is the one leaking. Was it a BMW seal? Don't know now but only a BMW one is going in. I did replace these when I did the clutch along with all the other seals and things you can do when the trans is out. Nothing else leaked so far.

[bubbafett]

I love when Randy explains things; he has a portfolio of pics to illustrate what he is saying. -- What loctite red # are you using in the seal corners Randy?

[Randy Forbes]

I love when Randy explains things; he has a portfolio of pics to illustrate what he is saying. -- What loctite red # are you using in the seal corners Randy?

#518, this is the tube, but the syringes are nice for stuff too.