Flywheel oil seal leak

[StewRat]

This probably isn't really hi-po specific, but the general online advice is all over the place so I'd appreciate experience/guidance from you guys.

The pleasure in getting my engine running faded somewhat when I realised there were a couple of pretty significant oil leaks.

The first one looked like it was oozing out of the 3/4 barrels but turned out to be the oil cooler blanking plate - that was easily fixed.

More troublesome has been the leak between the engine and transmission. I'm as sure as I can be it is the flywheel oil seal - the camshaft plug looked clean and I have spackled some extra sealant over it on one of the attempted fixes, and I can't see any signs of oil working through that.

So, on the flywheel oil seal ...

Good news is I'm getting lots of valuable practice at removing and reinstalling the engine. Bad news is I still have a leak.

When I first removed the engine to look, I was prepared to believe I had cocked the seal somewhat on installation - and the thin sealing lip had been torn a bit.

New seal fitted, using the old seal to install and driven just below the face of the recess - still leaking, albeit a little less than first time.

Next attempt, fitted to be flush with the face of the recess - leaks worse.

BTW, new flywheel o-ring fitted along with the seal.

There's enough online chat, videos etc to suggest this isn't uncommon, with advice varying from fitting flush, just below, and driven fully home. I was thinking I can dismiss the drive fully home version, but I'm now wondering if I understand how this seal works. My interpretation is that the flexible lip inside the seal is pressed against the curved part of the flywheel right?

Doesn't feel like it should be this hard.

So before I try again ...

1. I'm planning to buy the fitting tool to ensure the correct depth. How guaranteed is that?
2. I've been buying genuine VW seals from VW Heritage - anything better I should be using?

Thanks for any tips before the next attempt!

Stewart

[Tufty65]

1.Do you oil the seal before replacing flywheel?

2.Scoring on the actual flywheel surface causing it to burn up.

3.Case needs align boring as the crank assembly won't run true causing seal wear.

I put my seals just lower than flush,  not right back, just where the tapered edge stops.

[StewRat]

1.Do you oil the seal before replacing flywheel?

2.Scoring on the actual flywheel surface causing it to burn up.

3.Case needs align boring as the crank assembly won't run true causing seal wear.

I put my seals just lower than flush,  not right back, just where the tapered edge stops.

Thanks for the thoughts.

1. Yes - although the engine did sit for a bit at one point so the benefit of that may have been lost. It would only account for the first seal catching and tearing. Others have been fit and run.
2. Brand new flywheel and is clean smooth and shiny.
3. In fact engine is all new. It's not impossible there is something out of true but I haven't seen any other signs of it.

Thinking about "wear" etc - as there is some end play in the crankshaft, presumably the design of the seal means it can handle that, so the seal around the flywheel I guess is more than that final thin flexi lip and the flywheel must be reasonably well pressed into the seal. I'm as sure as I can be with a torque master tool and torque wrench that the flywheel is fully seated. It would be great to be able to spin the engine and build oil pressure without the trans to see better what is happening.

Stewart

[neil68]

There's enough online chat, videos etc to suggest this isn't uncommon, with advice varying from fitting flush, just below, and driven fully home. I was thinking I can dismiss the drive fully home version, but I'm now wondering if I understand how this seal works. My interpretation is that the flexible lip inside the seal is pressed against the curved part of the flywheel right?

After trying the flush or slightly below methods 20+ years ago, I switched to driving the seal fully home and have been leak free ever since.  Use the orange silicone Elring seal and make sure the flywheel flange is perfectly smooth (clean up with emery cloth, if need be).

If I'm reinstalling the same seal, with no change in end float, I place the seal in position before closing the two case halves.

[andy M.]

the seal is meant to go in as far as it can, simple as that

[Jim Ratto]

Use an Elring seal. Polish the nose of the flywheel on the OD to remove any imperfections. Use only a Elring or orig VW graphited o-ring. Make sure flywheel is surgically clean @ mating surface (to crank) and in o-ring groove. Apply engine oil to ID of seal.

[StewRat]

Thanks for all those comments guys.

Just goes to show - the option I thought was obviously wrong turns out to be most preferred here.

Third (or is it fourth) time is the charm.

Elring seal is on order and it is getting driven fully home.

Sometime soon I hope to be able to progress to finding out if my gears and brakes work ...

Stewart

[fish]

I always install Elring seal completely seated and also apply Aviation to the OD, 50/50 oil/STP ID.

[Tufty65]

1.Do you oil the seal before replacing flywheel?

2.Scoring on the actual flywheel surface causing it to burn up.

3.Case needs align boring as the crank assembly won't run true causing seal wear.

I put my seals just lower than flush,  not right back, just where the tapered edge stops.

Thanks for the thoughts.

1. Yes - although the engine did sit for a bit at one point so the benefit of that may have been lost. It would only account for the first seal catching and tearing. Others have been fit and run.
2. Brand new flywheel and is clean smooth and shiny.
3. In fact engine is all new. It's not impossible there is something out of true but I haven't seen any other signs of it.

Thinking about "wear" etc - as there is some end play in the crankshaft, presumably the design of the seal means it can handle that, so the seal around the flywheel I guess is more than that final thin flexi lip and the flywheel must be reasonably well pressed into the seal. I'm as sure as I can be with a torque master tool and torque wrench that the flywheel is fully seated. It would be great to be able to spin the engine and build oil pressure without the trans to see better what is happening.

Stewart

When you say it has some 'wear' in end play,  is it out of spec? if it's lots, as in you can see the flywheel moving in and out with the bare eye then that will most probably be the cause as it will put pressure on the seal every time you press the clutch.

I'd try driving the seal fully or almost fully home and see if that helps.

[StewRat]

End play was in spec when I built it and it's hardly run since then - in the post above I was mainly thinking aloud visualising how the seal worked.

I've bought the tool that is supposed to ensure the seal goes in right, so my plan for this weekend is to try again with that and some aviation on OD.

I'll double check end play before I take it apart just to be sure. (Not that I've got as far as putting it in gear with the engine running yet!)

Fingers crossed.

[mr horsepower]

mayby a little tip
at some automatic transmissions
mecanics drive the seal to far in
so that it block the drainhole
and it wil leak and the seal is in good shape
so check if your drain hole is not blocked
the oil has to go somewhere
and i acts like an hydrolic pump
just a tip
gr henri

[StewRat]

Thanks for all the suggestions.

Result of the weekend testing is ...

I put a new seal in with the CSP tool and it still leaked.

I wasn't sure that tool put it fully home, so second time round I used the tool and an old seal to ensure (?) it was pressed fully home.
Plus some permatex on OD. But checked oil return was clear.

( getting really good at engine in/out - I can now put it back in first time yah!!)

The interesting part now is that there is no leak when the engine is running (cue leaping around patting on back etc etc) but when turned off, there is like a syringe squirt of oil and following drips into my basin.

The only way I can visualise this is that oil is escaping as designed out the case via the crank, and it is being swirled around behind the flywheel oil seal by the crank rotation, and being drained down the oil return hole, enough to stay in that space.

Then, when stopped, the swirling oil is levelling above the lip of the oil seal (drain is about 7-8 o clock) and dribbling out vertically.

So I dont have a good seal yet twixt flywheel and the seal.

Additional reading/research is leaning towards more sealant to be use but opinions are still all over the place about where this seal should sit. Flush, +1/16th, fully home etc.

Personally, I'm going to press on with finalizing everything else about the car - if everything else works, this will be my only problem. If in the process I find other things that need fixed, it may be one person can fix them all.

[baz]

I'm not offering advice as I'm unqualified,  however from reading the jmr crankcase prep guide he suggests opening out that oil drain hole by .5mm and chamfering the entry to aid oil return. Dunno if you have done this? Not sure it's needed either, but having read of your troubles I'd like to find out if this does need doing before I close my case up.

[Jesse/DVK]

Are you sure the o-ring in the flywheel is good? I had a massive oil leak when I had forgot to put one in..

[StewRat]

@Jesse - always worth remembering, but yes, I've actually been putting in a new o ring with every new seal, I think we are at 4 so far, with only a few minutes running on each one.

@Baz - interesting. I'd forgotten about JMR. I read those pages in the early days of preparing for this adventure and then forgot about them after sending money for his CD and never receiving it.
We may be the blind leading the blind, but I reckon that hole is where it is and the size it is specifically because all the oil shouldn't drain away too quickly. As you become intimate with your flywheel oil seal, it seems to me that the key part of it is the lip on the inside bore that is in contact with the flywheel. At rest, I reckon a pool of oil sits below the level of the drain hole, between seal and case, but above the lip of the seal, ready to be drawn up and around when running to lubricate the flywheel/seal interface right from the start. 

Increasing it by .5mm doesn't sound like it would change much, may be in the "no harm" category.

Right now, I'm going to change the oil, check if any crap in the filter after these first few run ins, make my electrics race-ready, put it on stands and test the gears and brakes, etc etc - all with this oil dribble. I know I need to fix it before I race it, but I may yet find something that means I take the engine apart anyway so I'm leaving it to last for now. I need to feel I'm making progress overall again. I've ordered some proper Permatex, so when the time comes I'll be combining that with the installation tool and double checking the oil drain is clear. If that doesn't fix it, it's been told it's going on Gumtree.

[Martin S.]

Get some help from a local VW guy. Problems like these are not easy to diagnose over the internet. With all new parts there can be problems and an experienced VW mechanic might be able to spot the problem easily.

[181]

make sure that the oil return hole behind the seal is clean. Make sure the oils seal is leaking. I once went through 3 seals just to find out that my cam plug was loose and was leaking oil under pressure. 

[StewRat]

make sure that the oil return hole behind the seal is clean. Make sure the oils seal is leaking. I once went through 3 seals just to find out that my cam plug was loose and was leaking oil under pressure. 

Appreciate you giving input on this.

I'm annoyed that 2 months on I havent solved this problem. Mainly a function of only having a few hours a week to work on the car.

I have checked the oil return hole is clear. Last weekend I had the car up on ramps so I could lie underneath and confirm the oil is coming from between engine and trans (it is) and not some sump/lower case leak.

I'm as sure as I can be that it isn't the cam plug. That's based on what evidence remains by the time I get the engine out. Maybe I need to place some evidence capture behind the flywheel next time - but that would be a definite in/out test and each time I put the engine in, I hope its going to stay there for a while (though I am becoming adept at removing it).

Donald DTH Harvey kindly refused my money to fix it as we went through everything I've done and checked, and it is what he would do. That conversation did identify the flywheel as a possible variable (maybe non-square), happens I had another one to hand, so I fitted that but no improvement.

This weekend will see another iteration. This time I'm going to measure everything and try to identify any dimensional reason the flywheel isnt sealing against that lip.

Then, if that fails, I'm going to invent a see-through bellhousing and flywheel that can be fitted to a test rig to watch what is actually happening behind that (*^(^*%*$ flywheel!

[Garrick Clark]

 Put a block under the oil pump to angle the engine . The oil should then be higher than the cam seal, leave it over night and look for a leak on the floor. If no leak fit the new crank seal, fit a new O ring to the flywheel. refit the flywheel and torque it to spec, angle the motor further so the oil height  is just over the  bottom of the crank  seal. Leave it over night and look for a leak in morning.

[Garrick Clark]

Check the engine case can breath properly too

[StewRat]

2 good ideas Garrick - thanks.

Both rocker covers and the filler neck are vented to a breather box, and no oil is being pushed out anywhere else, but I will try running the engine with them in a can to double check no pressure build up.

And yes, when the engine is out this weekend I'm going to progressively angle - to the cam seal then the crank.

Gives me something to try - and hopefully zone in on the source of the problem.

Thanks again.

Stewart

[Martin S.]

You said it was a new engine. What case did you use? I had a new VW Brazil factory case with a flaw in the thrust bearing saddle. Was your case line-bored?

[StewRat]

You said it was a new engine. What case did you use? I had a new VW Brazil factory case with a flaw in the thrust bearing saddle. Was your case line-bored?

I bought it pre-owned but unused. I was told it was a "CB Performance Super Race Case" though I think "Super Case" is what they actually call them. I didnt have it line bored subsequently.

The kind of problem you describe is what I'm now dreading, but after the next iteration of checking and refitting, I fear a more substantial tear down may be required to find the source.

[Garrick Clark]

Another idea for you. After you have done the ideas I gave you IF you find that the motor isn't leaking, then the next test is to start the engine up on the floor. Get 2 breeze blocks and sit the Heat exchangers / J tubes on these blocks , keep it level . Start it up, Get the motor up to running  temp, switch motor off. Basically heat cycle it. Do it a few times.
Just  don't  refit the engine to the vehicle till your sure its fixed.
nothing worse than refitting an engine to find its still not right.

[Garrick Clark]

 double post

[Martin S.]

You said it was a new engine. What case did you use? I had a new VW Brazil factory case with a flaw in the thrust bearing saddle. Was your case line-bored?

I bought it pre-owned but unused. I was told it was a "CB Performance Super Race Case" though I think "Super Case" is what they actually call them. I didnt have it line bored subsequently.

The kind of problem you describe is what I'm now dreading, but after the next iteration of checking and refitting, I fear a more substantial tear down may be required to find the source.

That's interesting because the flawed case I have was pre-owned and unused as well and looked brand new. It's probably a good idea to let a line-bore guy check your case before using it. If he thinks it could use a bore than go ahead and do it. My stock 71 bus has a leakage problem from that area too. When the engine was out for a gas tank repair, the main seal was replaced as a matter of course. Afterwards, the engine leaked so I had the spare case checked out and line-bored and it is going to be swapped soon. Everything about the low mile stock engine in that bus is perfect too so the leak is a head-scratcher. It will be interesting to see what the case looks like and I will send it to the line-bore guy to fix eventually. He only charged me $75 for the line-bore so it's a no-brainer, plus the oversize bearings are thicker afterwards.

[StewRat]

I'm not even sure I should admit this, but looks like I may have found the source of my oil leak.

The good news is it's neither the cam plug nor the flywheel oil seal - that's good news in that I probably have been doing them right all along.

The bad news is that it is soooo stupid that in addition to kicking myself, y'all have permission to kick me if you see me too. Talk about tunnel vision...

Removed the engine this morning and set it up at a tilt as suggested to see if the cam seal would drip. Went back this evening and there is a dribble of oil collected in the rim at the bottom of the case, and a trail leading round the rim and up to ... the galley plug.

In this case, of the 3 galley plugs that sit roughly in line with the cam plug, the rightmost of them has been replaced with a threaded plug. Non-standard, so in my rigid following of instructions while assembling the engine, it was never mentioned, so it was never checked/tightened. Looking back, I think I mentally wrote this off as being a threaded insert for one of the securing bolts or something, just never, ever dawned on me it was a galley plug.
Idiot.
I've tightened it up (it was loose enough to turn by hand)  and will check again tomorrow.

Fingers crossed ...

Stewart

[modnrod]

Hopefully you're good to go man, that would be great. Good to mention it too, for others.

When I think of some of the dumb stuff I've 1/2 done occasionally........   

[StewRat]

Good to mention it too, for others.

Thanks! exactly - that's what this is:

1) a public service
2) search engine fodder for the next gen builders/racers who are looking for "drag racing beetle" "flywheel oil seal" "recurrent" "persistent" "solution" +"solved"

[Neil Davies]

Fingers crossed for you Stewart! Been looking forward to seeing this on track for quite a while!