Mystery oil weep from rear of engine...

[RaceDiagnostics]

Well stripping everything out of the way has been very time consuming today.

First job was to strip the oil pan off my spare transmission, I don't want to scratch up the one on the car.

Then removed the down pipes and heat shields.

Seems like the nut (throttle position rod) had worked it's way off this bolt but didn't have an impact on the shifts.

Earth removed as well as this heat shield, not sure of the point of this shield.

Next, getting these oil cooler lines out the way, what a pita, took hours.

Couldn't get much on to this hex socket bolt in the cooler line retainer. It's between the subframe and the engine sump.

So I welded a short bit of hex into a bolt to get on to them better.

Not much clearance between the manifold and chassis.

 

[RaceDiagnostics]

Next, drained the torque converter.

Then swapped over the pans.

Access to the vacuum line at the back of the engine, another pita.

Likewise the bolt holding the dip stick tube was a knuckle buster.

Then on to the prop shaft. This 46mm spanner doesn't get used much.

Prop out.

That's all the prep work done, should get the trans out tomorrow.

 

[Ubique]

Looking at those photos, two things come to mind - Firstly, I wouldn't like to be doing that job on that type of hoist, it just looks like it'd be in the way too often.
Secondly, and it may have a bearing on your leak - it doesn't look like the fasteners are the type originally fitted, they look like fully threaded coated bolts with flat washers. Probably fine for most usage but looking at your original photos, they're also in use on the seal mounting plate, which could be the source of the leakage. The threads will allow oil to track and the washers will be too hard to seal against the bolt heads, typically, the bolts will have an oversized head to spread the load and the surface will be flatter than the pressed bolt head or a stamped and coated washer - and typically will have a stepped blind shank, all of which will - or should help prevent oil leakage.

 

[RaceDiagnostics]

The lift is not ideal but all I have, probably taking me 50% longer compared to a two post.

AI suggested that I should have coated the threads of the seal plate cover bolts (not in the workshop manual), so that may be it. I have pictures of every bolt I took off the engine during the rebuild and their replacements. Difficult to tell if these had a sealer on them, but they do look oily!

Replacements.

 

[Ubique]

The M6 x 15 & M6 x 20 bolts definitely have a blind shoulder (too short to call it a shank) which look tapered, although that could be shadow. Do you have any of the old fasteners available to compare to their replacements? the old washers are probably more malleable than their replacements too.

I can't recall the last time I saw fasteners without an enlarged head in lieu of, or a captive, engineered surface washer. Probably best I stay away from 'restoration' type stuff eh?

 

[RaceDiagnostics]

Yes, I've still got all the old hardware (all jumbled though), I'll compare tomorrow.

 

[RaceDiagnostics]

Seems like the LSD has come back to life since the last time a checked it.

 

[bricol]

I've got a very similar issue with my Lancia - had the engine out twice, replaced seals, sensors, gaskets, oil return hoses, the two sump gaskets, oil stat sealing washers . . . and still the thing insists on rust-proofing the offside suspension arm!

 

[RaceDiagnostics]

Feck me, that was a job!

PNDR connector and gear selector disconnected.

Scissor lift under transmission.

Front of drive shaft and speedo cable removed

Then the bell housing bolts, top ones virtually inaccessible.

Then the flex plate bolts.

Ready to split them apart.

And it's out, what a job.

Next the flex plate.

 

[RaceDiagnostics]

So what does it look like....

The top half of the cover plate is fairly dry, the bottom half wet.

Not obvious to me where the oil is leaking from as the entire bottom half is oily. Any thoughts?

I think I'll wash it all down then start the engine for a bit, going to annoy the neighbours though.

 

[Melvyn Best]

Should have read the whole post, the later pictures were added after I had replied

 

[Blobber]

Looks like it's not sealing to the crank, it looks oily and weepy at the bottom?

 

[Gareth_16V]

Looks like it's leaking in a few places - the seal to the crank looks suspect, as do some of the bolts holding the seal cover plate on. But it also looks like there's oil pooling around the bigger bolts that hold the bell-housing adapter onto the block, no? I think the sump to cover joint is a resultant of the oil travelling down from leaks higher up.
I think the plan of washing it off with brake cleaner or similar and then running for a little while might be the best way - if the neighbours will allow.

 

[colnerov]

Yeah, so that's the flexplate and torque converter back on then, or at least the ring gear. But it won't be keen to idle.

 

[RichardM]

Wash it off with brake cleaner, dust it with talc if you're going to run it.
Check the bottom of the seal, has something caught it?

 

[RaceDiagnostics]

Yeah, so that's the flexplate and torque converter back on then, or at least the ring gear. But it won't be keen to idle.

Haha, I hadn't thought how I was going to start it.

 

[Ubique]

I'm going to suggest the crank oil seal isn't the culprit, based upon there being no radial oil splashes. Every time I've had a crank seal leaking, there's radial splashes where it's been flung around. There's nothing on the flexplate either. I can see the flexplate fixings are blind so that rules them out, it looks to me like it's the fixings on the crank seal mounting plate that are weeping, allowing oil to run down and lodge in the block to sump joint, I'd also suspect the oil on the crankshaft seal is there by virtue of the design of the flexplate causing changes in air pressure alternately pushing air away and drawing it in - and the oil will follow suit when it's nice and warm.

 

[Cobbler]

It’s difficult to see, but it looks like there could possibly be a hole or damage to outer face of the seal wher the oil is covering it.

 

[RaceDiagnostics]

Well well well.

Today's, pics. First I washed down the are with brake cleaner.

The oil seal didn't like it, but recovered one it dried out. Didn't expect that.

Then removed the cover plate bolts, the lower ones had oil on them.

When cleaning out the bolt holes spotted this. Looks like the hylomar had failed.

Then I prized off the cover plate.

What a cock up.

I'll fit the new oil seal but not bother with the journal sleeve on reassembly. The "repair" seal sits on a fresh part of the crank shaft.

I'll have a sheet of 0.4mm gasket paper but it's thinner than the original oil pan gasket. I'll coat both sides in aviation pematex on reassembly. Any thoughts?

 

[Nederlands]

Be glad you found it.

Not always that simple

What size is the original paper?