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Help tracking leak -- maybe rear lifting eye ??

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MTribe

MTribe

Jedi Hopeful
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I'll send a beer to whomever can help me crack this one. I have two oil leaks on my TR6:

1. bell housing/engine plate interface (i.e. where the bell housing mates to the rear of the engine), ~few drops worth after driving

2. transmission/bell housing interface (i.e. rear of bell housing where it mates to transmission; I have HVDA conversion if that matters), ~1 drop/week

Just traced #1 to the rear lifting eye area--can anyone confirm these bolts go through to oil passages?

#2 is more tricky--I assumed the transmission face was leaking, but it appears dry. It's a freshly rebuilt W58 toyota unit, so new seals and RTV all around. I did notice some very slight traces of oil in the bottom of the bell housing next to where it mounts to the engine plate, so thought A-HA! Would it be crazy to think the lifting eye leak is entering the bell housing, then running along the bottom, and draining out the back of it? I tried to see if the bell housing was slanted uphill or down, but it was so close to parallel I couldn't tell. Has anyone seen this? Might be specific to HVDA kit?
 
Quite sure it's oil. Golden in color. But can't tell if it's engine or transmission gear oil (just changed engine oil).
 
Just tried an interesting experiment. The #2 leak had dripped a few drops on the garage floor.

Near the drips, I poured small amounts of engine oil, 75-90 gear oil used in the tranny, and brake fluid.

I darkened the room, then shined a UV light on each of the puddles. Each of the fluids fluoresces a little differently.

Based on this test, the leak actually looks like engine oil. But the gear oil fluoresces closely enough to the engine oil that's it's not entirely conclusive. I can say it's definitely not brake fluid, though! That hardly fluoresced at all (there's a hyrdraulic throwout bearing in there).
 
Just tried a poor man's viscosity test. The engine oil is 10-30, the transmission oil 75-90.

I ran my finger through each puddle, as if to "squegee" a line through each. The engine oil flows back together, "healing" itself, much faster than the transmission oil. This test would indicate it's engine oil.

Still suspicious of engine oil finding it's way all the way back there, though. I don't see a clear oil trace across the bottom of the bell housing...
 
The reason I ask id that Booby had an initial leak with his hydrolic throw out bearing.
 
DNK--I too had a faulty hydraulic throwout bearing the first time, and the residual fluid from that isn't helping matters.

Another test--I tried smelling the fluids, but couldn't tell any difference. Inspired by our dog, I tried the rapid inhales she does when she's sniffing something. Wow--it works! I was able to smell that the transmission oil has a more pungent and "burned" smell then the engine oil. This test would also indicate the leak is engine oil. That's 3 for 3...

But I just can't figure out how the engine oil is finding it's way across the bell housing. What do you guys think--would there be any trail there, or is oil good at covering it's tracks, so to speak?
 
DNK said:
Rear main seal , but I HOPE not.
Click to expand...

<span style="color: #660000">Don, a skilled or knowledgeable mechanic
I'm not. I have no air tools and therefore I could not
remove my flywheel when I changed out the busted clutch.
The original, leaky rear main seal remains and it still
leaks like almost no seal.

My bet is the rear main seal is leaking.

d</span>
 
DNK said:
The reason I ask id that Booby had an initial leak with his hydrolic throw out bearing.
Click to expand...

Booby? :laugh: Close enough...I've been called worse! LOL. For engine oil to get from the rear of the block to the Bell Housing Tranny seam would require it passing through the flywheel, pressure plate, and clutch......possibly ruining the clutch. So are your sure it's coming from inside the bell housing and not from the outside and running down the outside case forming a small drip? I get an occasional drop where the bell housing meets the engine but it's coming from the rear sealing block.....and it runs on the outside of the case and forms at the bell housing seam.

As far as the engine block goes, here's 3 areas for possible leaks
RearSealAssembly.jpg
 
Sorry Booby. Do that almost every time when I type your name .
Bobby ,there!

If the main seal was leaking wouldn't it drip from the same location. maybe I'm not following the post.
 
Don....that's where I'm confused too....maybe Booby is appropriate.... :laugh: ....If I'm reading correctly leak #2 appears to be where the HVDA Bell Housing meets the Toyota tranny. Engine Oil would have to travel pretty far to leak at that point but I guess it could leak from the rear of the engine down onto the bell housing and along the inside bottom of the bell housing and come out at the bell housing/tranny seam. With my picture above, I'm just trying to show 3 spots on the rear of the engine that "could" leak and have the oil run down the inside of the bell housing.
 
If that is the case then I'm with you ,engine leak. If he finds it he can come to my place and find all the leaks on the V8 Wedge :laugh:
 
Probably already suggested, but we used flourescent dye in the oil and it painted a neon highway back to the source of the leak and the travel of the fluid to its destination.Also would determine which fliud it is with presence or absence of the dye.
Elysium
 
There is a plug at the left rear of the cylinder head that opens directly into the oil galley for the head. The copper gasket around it could be leaking down. I don't believe that there is any oil oils possible from the engine lifting bracket.
 
Thanks for all the tips...

Elysium, I did try the dye in the engine oil in the process of tracking down some other leaks, and you're right, leak #2 at the bell housing/transmission wasn't particularly dyed. But both oils (gear and motor) actually fluoresce enough under UV light that it was hard to tell. Is there any harm in using 2 or 3 bottles of dye??

I did one final test--to see what angle the transmission would have to be for oil to flow from front to back in the bell housing.... there's some curvature in there, so had to be about 10 degrees from horizontal before anything would flow backward (used water so I didn't have to wait as long!). Not anywhere near that angle installed. So that threw a curveball since everything else pointed to engine oil, not transmission oil!

That led me to just say SCREW IT and put in a long day to brute force everything to rule everything out all at once...

I started at 11AM Thursday, and at 7AM Friday morning I had:

- re-sealed front bearing cap of transmission with Right Stuff

- checked front transmission oil seal (brand new, so looked fine)

- tightened hydraulic throwout bearing fittings, ensured no leaks

- removed flywheel and engine plate, verified 2" cam plug bone dry

- rear main oil seal was leaking ever so slightly--just damp, no drips

- a very nice oil trail on the engine plate pointed right to eye bolts for #1!--sealed with Right Stuff

What a long day it was, but a lot of fun. I'm getting good at taking the transmission out (at least for me)--2.5 hours from car to bench, including some experimentation with how little I could get away with removing!

So--I'll report back with results. Can anyone confirm the rear main oil seal is very hard to get to stop leaking entirely? I don't know what I could have possibly done differently since I *just* replaced it on an engine rebuild. Any tricks there?
 
MTribe.........Glad to see you tackled all that work but I thought I'd share what I just found after getting my car up jacks for this winter's work. I can't really call these leaks because they're nothing more then a very rare drop on the floor but if I hadn't looked very closely I would have guessed that I had a leak at the bell housing/tranny seam. The Red arrows point to the leak source.....those darn pan bolts that go into the alloy cover for the rear seal. The oil runs down the back plate and mostly forms as a drip at the bell housing/back plate seam shown by the green arrow. But then I found a wetness at the BH/Tranny seam, black arrow, which is what you had as I recall. Upon closer inspection I could see where the wetness traveled down the BH (Blue line)to reach that seam. It's all the same oil from the same source. Because we usually have very clean oil in our cars, it was very difficult to spot the wetness between the green and black arrows. Too bad I wiped this whole area down before taking the picture.

OilLeak.jpg
 
BobbyD- Could you pop on over to the island
and install the rear engine seal for me?

I was unable to get the flywheel off when Dave and
I replaced the clutch. We had no air tools.

thanks,

dale
 
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