Crankshaft rear seal didn't fix the oil leak

[QB93Z]

My problem started with an oil drip from the forward edge of the bell housing on my 1993 ZR-1 (102K miles). I guessed that it was oil leaking from the crankshaft rear seal.

Yesterday I (we) replaced the crankshaft rear seal, seal housing gasket and clutch. Thanks to all who helped. :thumbsup:

I drove about fifty miles in the evening and parked it in the garage. This morning I have oil that dripped from the bell housing again.

My conclusion now is that the oil is coming from the transmission input shaft seal.

Anyone have any other ideas where the oil could come from?

Is replacing the transmission input shaft seal easy or will I have to rebuild the whole transmission to do it?

Thanks, Jim

[A26B]

Jim,
When you replaced the rear crank seal, where did you notice the oil leak "mess' in particular? If it's the rear seal, the mess should be confined to an area in the bellhousing between the flywheel & rear of the engine. A tranny seal would be confined to the rest of the bellhousing area, i.e. from the flywheel to the trans side of the bellhousing.

The trans input shaft seal should be accessible by removing the trans input shaft housing, with no further disassembly. Not a big job.....once you get the trans out. Any chance it might be overfilled? Should be level with the bottom of the fill plug.

[Pete]

Jim the trans seal is easy of course after you remove the trans from the car.

I really haven't seen many leaky trans seals but then i haven't seen too many high mileage Z's.

Anyway the seal is easy to repalce no need for taking the trans apart.
It's in the input shaft housing the one with all the allen socket head screws take off the allen screws housing will come off the seal is in the housing.

The other issue is finding the seal, it only comes with the complete gasket set $200+.
I'm pretty sure if you take the seal to your local parts store it could be match up to something like an axle seal.

Gaskets for the the ZF are available from Flatout Gaskets,no seals.
I'm using Flatouts trans gaskets with no issues for over a year.
http://www.flatoutgroup.com/

Pete

[Pete]

Jim also make sure your PCV system is up to par.

If your running one PCV valve or are not 100% the motor will push oil out the seal, seen that on 2 LT5's.

Just a thought or something to look into to.

Pete

[QB93Z]

Jerry, Thanks for the info. Here is the rear seal area immediately after the seal housing was removed, part of the old gasket is stuck at the top. The bolts holding the seal housing were basically finger tight so we thought we had found the source.http://i407.photobucket.com/albums/pp152/QB93Z/2009%20Aug%20Crank%20Shaft%20Seal/DSC02270.jpg

The inside of the bell housing was a mess all over. I couldn't determine an area that was the leak source. I cleaned it up so when I pull it again, I may get an indication.

Good to hear about the transmission input shaft seal being easy to replace. When I started this job I got a transmission rear seal from Advance Auto. When we pulled the transmission, it was obvious that they gave me the input shaft seal instead, so it was exchanged for a rear seal. I guess I should have kept it.

Jim

[QB93Z]

Jim also make sure your PCV system is up to par.

If your running one PCV valve or are not 100% the motor will push oil out the seal, seen that on 2 LT5's.

Just a thought or something to look into to.

Pete

Thanks Pete. :thumbsup: I will check it out.

[flyin ryan]

Sure does look like it was the rear main, doesn't it Jim? Strange...:confused: :dontknow:. Keep diggin'.

[tccrab]

Hmmm..
I was going to suggest the possibility of blow by from the oil box under the plenum dripping down the hole and then out onto the crank.
But I don't see enough crud around the block drain hole.
:dontknow:
Rear main seal seems the most likely candidate.
Having a hard time seeing how the front seal on the input shaft of the ZF6 could cause a drip there. I would have thought that the flywheel/clutch/pressure plate would have blocked any tranny oil from reaching the rear main area.

TomC
"Crabs"

[flyin ryan]

Maybe...Just maybe, the seal was hooped from new or somehow was nicked or damaged when installing? Sure looks like that was/is the culprit :neutral:.

[QB93Z]

Further investigation, no answer yet.

Here is a picture showing where the oil drips from:
http://i407.photobucket.com/albums/pp152/QB93Z/2009%20Aug%20Crank%20Shaft%20Seal/DSC02312.jpg

There is no fresh oil on the back or bottom edge of the oil pan:
http://i407.photobucket.com/albums/pp152/QB93Z/2009%20Aug%20Crank%20Shaft%20Seal/DSC02314.jpg

I checked the oil level in the transmission. Not very accurate, but using the pinky finger test, the oil level seems to be at the level of the plug. It appears that I have not lost any transmission oil.

I will investigate the PCV system to see if maybe the crankcase is feeling pressure. And I will be pulling the plenum to look for oil.

Jim

[Jagdpanzer]

Jim,
Remove the front bellhousing cover and see if the oil is coming from the valley drain tube or the crankshaft seal area.

[QB93Z]

Jim,
Remove the front bellhousing cover and see if the oil is coming from the valley drain tube or the crankshaft seal area.

Here's the visual: Jim smacking his forhead and saying "DOH"

Good idea Phil. :thumbsup: I will give it a try. I have a snake camera I just might be able to get up there.

Stay tuned.

Jim

[tomtom72]

That's the cleanest looking oil I've ever seen. Sure looks like it's fresh, ofcourse fresh 10w-60 TWS oil is the same golden color.

:o Just an observation about the color and the absence of any blackening..:redface:

Tom

[Scrrem]

Jim,
When we had the transmission out, I did notice oil coming from the passenger side valve cover area. Would it be possible that this is leaking bad enough to run down to that same area?
Rich

[QB93Z]

I removed the bell housing dust cover plate and looked around. There was no detectable oil coming from the crankshaft rear seal housing, but it hard to see at that angle. There was an oil drip at the end of the valley drain tube.

I started by inspecting the PCV valves and tubing. I didn't see any obvious defects.

So, I have pulled the plenum, coil packs tray, and the starter. The valley is a mess, and there is a lot of oil as well as 102K miles worth of grime. I plan to clean it up and then clear the interference and torqe the crank case vent housing bolts. The two vent elbows look OK.

Now some more questions:

Why are there two different PCV valves? How do you tell if a PCV valve is bad?

Jim

[tomtom72]

I don't know why we have a left & right.:dontknow:

I check mine about 1/2 way thru the season and always wind up spraying carb cleaner in them to free them up. You should be able to shake them and hear the check valve rattling. When they get dirty the sound goes from a metallic tic, tic, to more of a thud, thud.

I just replace mine every year.

Ya know Jim, if the valley tube was even a bit loose fitting at the top then it could be reasonable to expect the oil to miss the tube and run down the back of the block & come out at the bottom. My CCVB bolts were so loose that the oil was all over the place under my plenum and on that corner of the oil pan where the tube exits.

:cheers:
Tom

[QB93Z]

I don't know why we have a left & right.:dontknow:

I check mine about 1/2 way thru the season and always wind up spraying carb cleaner in them to free them up. You should be able to shake them and hear the check valve rattling. When they get dirty the sound goes from a metallic tic, tic, to more of a thud, thud.

I just replace mine every year.

Ya know Jim, if the valley tube was even a bit loose fitting at the top then it could be reasonable to expect the oil to miss the tube and run down the back of the block & come out at the bottom. My CCVB bolts were so loose that the oil was all over the place under my plenum and on that corner of the oil pan where the tube exits.

:cheers:
Tom
Thanks for the info Tom.

Did you remove the CCVB and replace the gasket or were you able to stop the leaks by just torqing the bolts that can be reached without removing the AC compressor?

The valley drain tube was firmly installed. We removed it, cleaned out the drain hole, and reinstalled the tube securely (Thanks Phil).

When I removed the bell housing lower front cover last night, I noticed that it has a curved indentation that matches the location of the valley drain tube. This arrangement causes any drainage from the valley to go INTO the bell housing. Because the top edge of the lower front cover is not connected to the block or the oil pan, any leakage from the crankshaft rear seal housing or the back of the block would run down the back of the oil pan not into the bell housing. It is hard to say where any oil leaking past the crank shaft seal itself would end up.

Jim

[tomtom72]

Yes, I was doing my injectors and had a top end gasket kit from Kurt so I just replaced the old gasket because I had it. The A/C compressor I un-bolted the comp & the mount (?) if I remember right and moved it forward & rested it on the right side of the rad shroud. No system dump of the gas as there is enough slack in the hoses to move the comp out of the way. I do believe I had to remove the linkage for the secondaries along with the linkage shields to get the CCVB cover off, I think. I replaced the hoses also as I had them too. The mess was huge from the bolts being loose!

I swear that my valley tube ends at the right rear corner of my pan, that's where all my oil was ending up and on the ground!

:cheers:
Tom

I used an old T/Q'ing sequence from the old MoPar wedge motors on the box cover, an X or a circular pattern. They had this flat metal pan that went under the intake mainfold to seal the velley. I rechecked the T/Q on my cover bolts two yrs ago and they were still tight. Oh, forgot, I used some blue thread locker too on them suckers. My bolts were finger tight!!!

[A26B]

Jim,
Tom is correct about removing the secondary linkage shield to get the CCVH out for gasket replacement. I'm not one to recommend short cuts, but I would suggest that you consider leaving it in place & just tightening the bolts (13 if I remember right). You could snug down the corner bolts to start, then remove bolts, clean the oil off, apply a little thread lock & replace until all were done. I found the same problem on my '94 at 68K miles before the 415 build and did this procedure. No further leaks.

I fixed the oil pan leaks the same way & it worked fine.

Good luck Jim.

[QB93Z]

Thanks Tom. Thanks Jerry.

I had come to the same conclusion. I will try an incremental approach and see if tightening the bolts and grooming the PCV system will solve the problem.

Jim

[Jagdpanzer]

Jim,
I have some new PCV valves if you need em.

[QB93Z]

Thanks Phil, I have a set that I put in.

Update: I pulled the plenum, coil pack and the starter. I cleaned everything up, torqued down the CCVH bolts, and tightened up th event elbows. also, I put in two new PCV valves and cleaned up all the tubing. Put it all back together and drove 25 miles this evening.

No drip upon return to the garage, but I will wait til morning and look for the small oil puddle that I was getting before.

Only problem is that the secondaries hesitate about a half second before opening. They never did that before. So I guess I will pull the plenum and groom the secondary vacuum system again.

Keeping my fingers crossed on the oil leak.

Jim

PS: Thank you to everyone for all the advice and wisdom! :thumbsup:

[Scrrem]

Get news Jim, hope that gets it!
Rich

[QB93Z]

Bummer!

There was a small puddle of clean looking oil under the bell housing this morning. :mad:

So, I guess the next step is to figure out if the transmission is leaking out of the input shaft seal.

But it will have to wait til I take a ten-day trip in 1994 ZR-1.

See you when I get back.

Jim

[Aurora40]

Now some more questions:

Why are there two different PCV valves? How do you tell if a PCV valve is bad?
The two valves are different. My assumption is that they wanted some kind of flow scenario that one valve didn't accomplish. Like maybe some amount of leak at X amount of vacuum/pressure, then ramping up to some amout Y at some different vacuum/pressure.

Like Tom said, the only way I know to check them is to shake them and make sure the valve still moves freely. But really once you get to that point and they are original, you may as well just swap 'em out. :)

[Aurora40]

As to the clean oil coming out, is there a way to add some kind of dye or something to the engine oil or trans oil so that you can tell which the leak is from?

[secondchance]

As to the clean oil coming out, is there a way to add some kind of dye or something to the engine oil or trans oil so that you can tell which the leak is from?

That's a great idea. I guess both have to be clean and finding a dye that won't have ill effect. But then it will be drained and replaced after the fact except motor will always retain 25%.

[Jeffvette]

The two valves are different. My assumption is that they wanted some kind of flow scenario that one valve didn't accomplish. Like maybe some amount of leak at X amount of vacuum/pressure, then ramping up to some amout Y at some different vacuum/pressure.



Bob s correct. THere are two PCV valves to help push the crankcase air out. The motor has two different characteristics and one valve was not enough. GM/Lotus had problems maintaining oil control.

Just replace the valves. They are cheap, and probably need to be replaced anyways.

Jim, the other option is you can remove everything, and fire up the motor and run it and see if you get any seeping. Just wear good ear and eye protection when doing so.

[Jagdpanzer]

As to the clean oil coming out, is there a way to add some kind of dye or something to the engine oil or trans oil so that you can tell which the leak is from?

Easy, drain the engine oil and refill with Royal Purple oil.

[phrogs]

or some kind of dye so you can determine if its the engine or the transmission and then start to trouble shoot it.

[flyin ryan]

Easy, drain the engine oil and refill with Royal Purple oil.Grape juice :cool:.

[tomtom72]

Okay, I don't know of a dye, maybe water based food coloring?

This thought just hit me. The trans fluid is new? The motor oil will get contaminated with blow by & turn dark, almost black. Why not wait till that happens then compare colors? It shouldn't take all that long. Or not.

I know, I know, I'll go........ :redface:

[A26B]

There is a dye for engine oil, available at auto parts stores. Ryan knows that, he's just being a wise azz because he know his winter is just around the corner.

PS Tom, you let your oil get black before changing? Naughty naughty, bad Tom!

There is another way. Drain all the oil out of either the engine or tranny, drive it around a bit. Then if it still leaks you know where it came from.:jawdrop:

[QB93Z]

...There is another way. Drain all the oil out of either the engine or tranny, drive it around a bit. Then if it still leaks you know where it came from.:jawdrop:

Thanks for the advice Jerry. Have you tried that approach? My idea is to drain the oil out of both and then no more oil leak.


Well, back from vacation now. I put oil UV dye in the transmission. Drove to Bill's for a beer or two. The leaking oil is coming from the transmission.

The UV dye is pretty neat. The oil has a slight tint to it, but as soon as I turned on the UV light, it glowed light green. I discovered that I had dripped it all over my bench as well.

So I will be pulling the transmission soon to replace the input shaft seal.

Jim

[ZR-1nce removed]

Thanks for the advice Jerry. Have you tried that approach? My idea is to drain the oil out of both and then no more oil leak.


Well, back from vacation now. I put oil UV dye in the transmission. Drove to Bill's for a beer or two. The leaking oil is coming from the transmission.

The UV dye is pretty neat. The oil has a slight tint to it, but as soon as I turned on the UV light, it glowed light green. I discovered that I had I had dripped it all over my bench as well.

So I will be pulling the transmission soon to replace the input shaft seal.

Jim


Standing by waiting to assist the Captain!

[Scrrem]

So I will be pulling the transmission soon to replace the input shaft seal.
Jim

If you need any "Expert Supervison".....I'm your man :mrgreen:
Rich

[QB93Z]

Thanks Rich, definitely!

Darrin, think we can swap the tranny and replace your leaf spring in the same day? Let me know when you get your bushings. Better yet, get me a set too, I'll pay you back.

Jim

[A26B]

Thanks for the advice Jerry. Have you tried that approach? My idea is to drain the oil out of both and then no more oil leak.
Jim

No, haven't tried it myself, but I like your's better. "We don't need no stinkin' oil"

Glad you located the leak Jim. You got zippers on the tranny now?

Take care,
Jerry

[QB93Z]

No zippers, but I did use ball-lock pins instead of bolts to secure the transmission.

Jim